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Oxytocin is clearly involved in human reproduction and serves an important role in sexual arousal. Oxytocin serum levels were measured before and after sexual stimulation in 12 healthy women. Values of oxytocin 1 min after orgasm were significantly higher (p < 0.05) than baseline levels. This finding supports the hypothesis that oxytocin plays a major part in human sexual response both in neuroendocrine function and postcoital behavior.
Original Paper
Gynecol Obstet Invest 1999;47:125–126
The Role of Oxytocin in Relation to
Female Sexual Arousal
Wibke BlaicheraDoris GruberaChristian BieglmayeraAlex M. Blaicherb
Wolfgang KnogleraJohannes C. Hubera
Department of aGynecology and Obstetrics, Division of Gynecological Endocrinology and Reproduction Medicine,
and bDepartment of Anesthesiology and General Intensive Care, University of Vienna, Austria
Received: March 17, 1998
Accepted: May 5, 1998
Wibke Blaicher, MD
PO Box 41
A–1097 Vienna (Austria)
Fax +43 1 409 51 51, E-Mail
Fax + 41 61 306 12 34
© 1999 S. Karger AG, Basel
Accessible online at: /karger
Key Words
Oxytocin W Human W Sexual arousal
Oxytocin is clearly involved in human reproduction and
serves an important role in sexual arousal. Oxytocin
serum levels were measured before and after sexual
stimulation in 12 healthy women. Values of oxytocin
1 min after orgasm were significantly higher (p ! 0.05)
than baseline levels. This finding supports the hypothe-
sis that oxytocin plays a major part in human sexual
response both in neuroendocrine function and postcoital
Oxytocin (OXY) serves an important role in the sec-
ond stage of labor [1] as well as in the lactokinetic reflex
with nipple stimulation during breast-feeding [2]. It is
supposed to rise during sexual arousal and peak during
orgasm in women and in men, which is possibly the
response to areolae or genital tract stimulation. As pre-
vious studies demonstrated, there are variations in OXY
levels as well as of female sexual interest during the men-
strual cycle [3]. OXY peaks at time of ovulation and
remains significantly elevated in the follicular phase when
compared to the luteal phase [4].
Although the nature of the interaction between OXY
and other hormones in the process of female sexual arous-
al, receptivity, and maternal behavior is not clear, the
OXY-releasing effect of genital tract stimulation has been
described in animal models [5, 6].
The purpose of the investigation was to quantify serum
OXY concentration in relationship to sexual arousal in
human females.
Materials and Methods
After the approval of the institutional review board and written
informed consent, we investigated 12 healthy unmedicated females
aged 23–37 years with regular ovulatory cycles (mean 28 B 4 days).
Ovulation was confirmed by a progesterone serum level 13 ng/ml
7 days before the expected menstruation cycle. The investigation was
performed on day 14 of the menstrual cycle. Venous blood samples
were collected before, exactly 1 and 5 min after masturbation.
OXY Analysis
Blood was allowed to run freely into chilled EDTA tubes. Trasylol
(0.5 ml) was added per 10 ml blood and the tubes were spun in a
refrigerated centrifuge. The plasma samples were stored at –70 °C.
OXY was measured with radioimmunoassay (RIA) kits from Phoe-
nix Pharmaceuticals, Mountain View, Calif., USA. We thawed the
plasma samples in an ice-bath and added 2 ml 1% trifluoroacetic
acid (TFA) to 2 ml plasma. These acidified samples were centrifuged
at 6,000 g for 30 min. C-18 columns (200 mg, Sep-Column, Phoenix)
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Gynecol Obstet Invest 1999;47:125–126
Table 1.
OXY values (in pg/ml) at baseline, exactly 1 and 5 min after
orgasm in 12 female volunteers
No. Baseline 1 min
after orgasm 5 min
after orgasm
23.6 42.9 28.2
2 10.4 11.7 8.1
3 13.7 14.9 17.0
4 8.6 9.2 8.9
5 8.6 10.3 11.7
6 8.3 10.0 8.1
7 20.0 20.8 22.8
8 17.8 18.6 18.3
9 8.6 8.8 6.9
10 6.2 6.9 5.2
11 4.9 6.3 7.9
12 6.9 7.6 7.7
were activated by passing through of 1 ml 60% acetonitrile (AN) in
1% TFA followed by three times 3 ml 1% TFA. The sample superna-
tants were layered on top of the activated columns and consecutively
the columns were washed twice with 3 ml 1% TFA. Peptides were
eluted by 3 ml 60% AN in 1% TFA. This solid phase extraction pro-
cedure was carried out automatically by an Aspec XL (Gilson,
France). Sample tubes as well as eluate tubes were kept cool at 4°C.
Duration of an activation and extraction cycle was about 20 min.
Eluates were evaporated at room temperature by GyroVap centri-
fuge (Howe, UK) and the residues were dissolved in 250 Ìl assay
buffer. For setting up the OXY RIA we followed the manufacturer’s
protocol. Radioactivity was measured by a crystal scintillation coun-
ter (Wizzard 1470; Wallac, Finland) and data reduction was per-
formed with the Multicalc software (Wallac).
The extraction yield of an OXY standard mixed with plasma was
190%. Linearity of the dilution behavior for extracts was tested and
there was no drift in results during sample extraction.
Statistical analysis was done using Wilcoxon’s test for paired sam-
ples with p ! 0.05 considered to be significant. Data are expressed as
mean B SD.
Each subject showed an OXY increase 1 min after
orgasm. At baseline the mean OXY serum level was 11.53
B 6.08 pg/ml and increased significantly to 14.00 B
10.00 pg/ml (p = 0.0033) 1 min after orgasm, and de-
creased at 5 min to 12.56 B 7.30 pg/ml. OXY levels of 5
subjects did not return to baseline levels 5 min postmas-
turbation (table 1).
Our measurements confirm animal research data, that
genital tract stimulation results in an increased OXY
release immediately after orgasm. Both OXY plasma lev-
els and nerve growth factor (NGF) plasma concentration
have been shown to increase during labor and lactation
[5]. These findings suggest that there is an interaction
between OXY and NGF which seems to play an impor-
tant role during labor and gestation as well as in terms of
sexual excitement and orgasm. Further research is neces-
sary to determine whether the intracoital OXY release has
a psychotropic dimension in respect of the ongoing rela-
tionship between man and woman. These findings may
lead to a new interpretation of sexual intercourse and
offer a new evolutional perspective.
1 Steer PJ: The endocrinology of parturition in
the human. Baillieres Clin Endocrinol Metab
2 Freund-Mercier MJ, Moos F, Poulain DA, Ri-
chard P, Rodriguez F, Theodosis DT, Vincent
JD: Role of central oxytocin in the control of
the milk ejection reflex. Brain Res Bull 1988;
3 Dennerstein L, Gotts G, Brown JB, Morse CA,
Farley TMM, Pinol A: The relationship be-
tween the menstrual cycle and female sexual
interest in women with PMS complaints and
volunteers. Psychoneuroendocrinology 1994;
4 Amico JA, Seif SM, Robinson AG: Elevation of
oxytocin and oxytocin-associated neurophysin
in the plasma of normal women during midcy-
cle. J Clin Endocrinol Metab 1981;53:1229–
5 Anderson-Hunt M, Dennerstein L: Oxytocin
and female sexuality. Review. Gynecol Obstet
Invest 1995;40:217–221.
6 Chan A, Dudley CA, Moss RL: Hormonal and
chemical modulation of ventromedial hypo-
thalamus neurons responsive to vaginocervical
stimulation. Neuroendocrinology 1984;38:
7 Luppi P, Levi-Montalcini R, Bracci-Laudiero
L, Bertolini A, Arletti R, Tavernari D, Vigneti
E, Aloe L: NGF is released into plasma during
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... Since the pioneer studies. [29][30][31][32][33] until the most recent published one, 34 all of them showed an increase of the oxytocin levels during, or immediately after, the orgasm or ejaculation. The task used has been the sexual self-stimulation that could be associated to visual sexual stimulation. ...
... Despite the relevance of the oxytocin in the social cognition and emotions, a limited number of studies investigated the role played by the oxytocin levels in human sexual behavior. The present systematic review took into account only studies that assessed the oxytocin levels without considering the randomized [28][29][30][31][32][33][34][35][36][37][38]40,41 In this way, given the subjective reports, it was not possible to quantify the intensity or the exact moment in which sexual arousal and orgasm occurred. Previous studies used psychophysiological techniques to record the variation of the penile circumference and vasocongestion of the vaginal wall during tasks like visual sexual stimulation. ...
... Most of the studies found higher levels, or at least peaks of oxytocin levels during the orgasm or ejaculation. [28][29][30][31][32][33][34][35][36][37][38] Overall, this seems to be confirmed by indirect evidence about women affected by anorgasmia that showed lower levels than orgasmic women. 36 Oxytocin is the hormone responsible for the uterine contractions during the labor 44,45 and it should be conceivable that a similar contractile mechanism during the orgasm is able to release, at the level of the neurohypophysis, higher amount of oxytocin. ...
Full-text available
Introduction Despite its role in social cognition and affiliative behavior, less is known about the role played by oxytocin in human sexual behavior. Aim In the present systematic review, we aimed to find the levels of oxytocin related to human sexual arousal and orgasm. Methods We conducted the study according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We performed a systematic search in the principal databases for studies that reported collection of salivary or plasmatic samples, with dosage of oxytocin in relation to sexual activity during induction of sexual arousal and orgasm. Results 414 articles were obtained. After duplicates removal and the application of pre exclusion criteria, 16 articles were considered eligible and 13 articles were included with a Cohen's k of 0.827. Most of the studies used sexual self-stimulation and collected plasmatic or salivary samples to measure oxytocin. The sexual arousal and orgasm were assessed based on subjective reports. Main Outcome Measure The primary outcomes were the oxytocin levels collected during the induction of sexual arousal and orgasm. Conclusions Several studies collected only subjective reports about the sexual arousal and the orgasm. Most of the studies found higher levels of oxytocin during the orgasm or ejaculation. Given the sexual arousal evoked by self-stimulation in which sexual fantasies play an important role, it should be possible to postulate for a role of the oxytocin in sexual desire. In particular, we hypothesize a complex role of the oxytocin in the modulation of sexual fantasies and thoughts that are relevant in the sexual desire and help to trigger genital and sexual arousal.
... Although some studies have reported that OT concentrations are increased in both sexes during sexual orgasm (Blaicher et al., 1999) or in response to social touch , and may act synergistically with estrogen (Amico et al., 1981;Young et al., 1998;Patisaul et al., 2003;Salonia et al., 2005), there is still no compelling evidence that OT actually increases sexual desire in women and potentially the increased release following orgasm or in response to touch may function primarily to strengthen bonds between partners. Indeed, the study showing that OT facilitated social sharing behaviors in pair-bonded marmosets found no evidence that it increased female sexual behavior (Smith et al., 2010). ...
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In humans, the neuropeptide oxytocin promotes both attraction toward and bonds with romantic partners, although no studies have investigated whether this extends to the perceived attractiveness of flirtatious language. In a within-subject, randomized double-blind placebo-controlled behavior and functional magnetic resonance imaging (fMRI) paradigm ( ), 75 women rated the attractiveness of either a male face alone or paired with a verbal compliment which varied in terms of topic (women or landscapes) and figurativeness (novel or conventional metaphors or literal expressions). Subjects were tested in fertile and luteal phases of their cycle and on both occasions received either 24 IU intranasal oxytocin or placebo. Results showed that, whereas under placebo women in the fertile phase rated the facial attractiveness of men producing novel metaphorical compliments higher than in their luteal phase, following oxytocin treatment they did not. Correspondingly, under oxytocin the faces of individuals producing novel metaphorical compliments evoked greater responses in brain regions involved in processing language (middle frontal gyrus) and cognitive and emotional conflict (posterior middle cingulate and dorsal anterior cingulate) but reduced functional connectivity between the dorsal anterior cingulate and right orbitofrontal and medial frontal gyri. Thus, sex hormones and oxytocin may have opposite effects in regulating mate selection in women during their fertile phase. Novel metaphorical compliments convey a greater sexual than bonding intention and thus while sex hormones at mid-cycle may promote attraction to individuals communicating sexual rather than bonding intent, oxytocin may bias attraction away from such individuals through increasing cognitive and emotional conflict responses toward them.
... Das wurde im Hinblick auf sexuelles Verhalten bereits früh thematisiert (Carter, 1992;Smock et al., 1998) und stellt bis heute die interdisziplinäre Forschung vor Herausforderungen. Oxytocin spielt nicht zuletzt auch in das Paarungs-und Schwangerschaftsverhalten hinein (Borrow & Cameron 2012) und moduliert die sexuelle Erregung (Blaicher et al., 1999;Corona et al., 2016). ...
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Zusammenfassung Musik hat eng mit Erotik und Sexualität zu tun, von Liebesspielen in der Oper über die Sexualsymbolik im Kunst- und Volkslied bis hin zur sexuell stimulierenden Musik im privaten und gewerblichen Bereich. Auf der anderen Seite steht Sexualverhalten eng mit dem endokrinen System im Zusammenhang. Eine Verbindung zwischen Musik und Hormonen liegt daher nahe, was allerdings in der Forschung bislang weitgehend ignoriert wurde. Der vorliegende Beitrag versucht durch seinen Fokus auf den Zusammenhang von Musik mit Hormonen, die im Sexualbereich eine Rolle spielen, eine (mögliche) Brücke zu schlagen. Dabei kommen konkret Testosteron, Östrogen, Oxytocin, Endorphine und Prolaktin zur Sprache. Sollte sich tatsächlich ein engerer neuroendokrinologischer Zusammenhang zwischen Musik und Sexualverhalten – was noch Forschungsdesiderat ist – herausstellen, so liegen Auswirkungen auf die Sexualsoziologie und Sexualtherapie nahe. Im Kontext mit dem vorliegenden Beitrag bezieht sich das wesentlich auch auf interkulturelle Aspekte und die Altchinesischen Sexualtherapie. Schlüsselwörter Musik, sexuelle Erregung, Endokrinologie, Oxytocin, Sexualtherapie Abstract Music, erotic feelings, and sexuality go hand in hand, as witnessed by love scenes in operas, sex symbols in songs, and sexually arousing music in private an commercial areas. On the other hand, sexual behaviour is closely interconnected with the endocrine system. Hence there are good reasons to consider hormones the missing link between both domains. Given that until today this aspect has been widely ignored by science, this article tries to explore the relation between music and selected hormones that modulate sexual behaviour and/or play a crucial role for sex-associated processes: testosterone, oestrogen, oxytocin, endorphins, and prolactin. If it turns out that neuro-endocrine processes modulate the still heuristic connection between music and sexual behaviour, findings will probably have a strong impact on the sociology of sexuality and sex therapy. Research referring to these topics, however, is still lacking. In this context, the present article also highlights cross-cultural issues and takes Ancient Chinese Sex Therapy into consideration. Keywords Music, sexual arousal, endocrinology, oxytocin, sexual therapy
... Die Plasmaspiegel von Oxytocin sind während des Orgasmus bei Männern und Frauen erhöht (Murphy et al., 1990;Blaicher et al., 1999). Bei Frauen ändert sich der Oxytocinspiegel im Blut während des Menstruationszyklus (Engel et al., 2019). ...
... Oxytocin is an essential modulator of social behavior and cognition in eutherian mammals (Jurek and Neumann, 2018). In addition to its roles in core reproductive functions like sex, parturition, and lactation (Blaicher et al., 1999;Carmichael et al., 1994;Fuchs and Fuchs, 1984;Insel and Shapiro, 1992;Uvnäs-Moberg and Prime, 2013), preclinical studies manipulating oxytocin in the brains of non-human animals indicate more subtle effects on social behavior and perception, e.g., in the context of affiliative behavior, partner preferences, pair-bonding, social touch, and stress reactivity (Dölen et al., 2013;Donaldson and Young, 2008;Hung et al., 2017;Menon et al., 2018;Neumann et al., 2000;Ross et al., 2009;Tang et al., 2020). Studies of oxytocin in humans provide evidence of similar functions. ...
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Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking—particularly when performed together—and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.
... OXY widely facilitates acute sexual arousal [73][74][75], and, influenced by oxytocinergic neurons in the PVN, penile erections [76,77] and the orgasmic process [73,78]. The initial sexual encounter stimulates OXY secretion combined with the activation of synthesis in oxytocinergic neurons in hypothalamic nuclei [42]. ...
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We investigated the effects of sexual arousal induced by olfactory stimuli on the expression of neuromodulators, neurotransmitters and sexual steroid receptors in the suprachiasmatic nucleus (SCN, the circadian pacemaker of mammals) and other cerebral entities of Syrian hamsters (Mesocricetus auratus) compared to manual sleep deprivation and immobilization stress. The hamsters kept under a 12:12 hours (h) light:dark cycle were deprived of sleep by sexual stimulation, gentle manual handling or immobilization stress for 1 h at the beginning of the light phase and subsequently sacrificed at zeitgeber time 01:00, respectively; for comparison, hamsters were manually sleep deprived for 6 or 20 h or sacrificed after completing a full sleep phase. As demonstrated by immunohistochemistry, apart from various alterations after manual sleep deprivation, sexual stimulation caused down-regulation of arginine-vasopressin (AVP), vasointestinal peptide (VIP), serotonin (5-HT), substance P (SP), and met-enkephalin (ME) in the SCN. Somatostatin (SOM) was diminished in the medial periventricular nucleus (MPVN). In contrast, an increase in AVP was observed in the PVN, that of oxytocin (OXY) in the supraoptic nucleus (SON), of tyrosine-hydroxylase (TH) in the infundibular nucleus (IN), and dopamine beta-hydroxylase (DBH) in the A7 neuron population of the brain stem (A7), respectively. Testosterone in plasma was increased. The results indicate that sexual arousal extensively influences the neuropeptide systems of the SCN, suggesting an involvement of the SCN in reproductive behavior.
... Tops et al. [28] reported that high levels of cortisol lead to an increase in oxytocin levels. Oxytocin typically increases during sexual intercourse and is thought to play a key role in sexual arousal and orgasm [29][30][31][32]. In a small study of 12 men with autoimmune PAI, Granata et al. reported an association with many sexual dysfunctions, with a significant improvement of some parameters after cortisol replacement therapy. ...
Full-text available
Purpose: No data are currently available on female sexual dysfunction (FSD) in primary adrenal insufficiency (PAI) and the possible impact of replacement therapy. The aim of this study was to evaluate the prevalence of FSD and sexual distress (SD), and to evaluate the possible impact of replacement therapy on sexuality in women with PAI. Methods: Female Sexual Function Index-6 (FSFI-6) and Sexual Distress Scale (SDS) questionnaires were administered to 22 women with PAI and 23 healthy women matched for age as controls. Results: The prevalence of sexual symptoms measured by FSFI-6 (total score < 19) was significantly higher in women with PAI (15/22; 68.2%) compared to the controls (2/23; 8.7%; p = 0.001). Regarding the questionnaire items, significantly different scores were found for desire (p < 0.001), arousal (p = 0.0006), lubrication (p = 0.046) and overall sexual satisfaction (p < 0.0001) in women with PAI compared to the controls. The rate of FSD (FSFI < 19 with SDS >15) was 60% in patients with PAI. A significant inverse correlation was found between FSFI-6 total scores and SD (r = -0.65; p = 0.0011), while a significant direct correlation was found between FSFI-6 total scores and serum cortisol levels (r = 0.55; p = 0.035). Conclusions: A higher prevalence of FSD was found in women affected by PAI compared to healthy women. Desire seems to be the most impaired aspect of sexual function. Moreover, sexual dysfunction in this population seems to be related to sexual distress and cortisol levels.
Male genitalia are subject to rapid divergent evolution, and sexual selection is believed to be responsible for this pattern of evolutionary divergence. Genital stimulation during copulation is an essential feature of sexual reproduction. In mammals, the male intromittent genitalia induces a cascade of physiological and neurological changes in females that promote pregnancy. Previous studies of the house mouse have shown that the shape of the baculum (penis bone) influences male reproductive success and responds to experimentally imposed variation in sexual selection. Here, we test the hypothesis that the baculum is subject to sexual selection due to a stimulatory function during copulation. We selected male and female house mice (Mus musculus domesticus) from families with breeding values at the extremes of baculum shape and performed two series of experimental matings following which we examined the concentration of prolactin in the blood of females either 15 (“early”) or 75 (“late”) min after ejaculation. Our results provide evidence of a mating-induced release of prolactin in the female house mouse early after ejaculation, the level of which is dependent on an interaction between the shape of the baculum and male sexual behavior. Our data thereby provide novel insight into the mechanism(s) of sexual selection acting on the mammalian baculum.
This study explored the role of the hormone oxytocin in 49 emerging adult couples’ communication after sexual activity. Guided by the post sex disclosures model, the findings indicated that post sex oxytocin levels, but not increases in pre to post sex oxytocin, were associated with men's general assessments of the benefits and risks of disclosing after sexual activity (measured separately from the sexual episode). Additionally, women's and men's benefit assessments were positively associated, and their risk assessments were negatively associated, with positive disclosures after sex. The findings offer the first known test of couples’ oxytocin levels during a naturally occurring sexual episode in the home environment and have implications for researchers interested in the links between oxytocin and human behavior.
Current evidence suggests that oestrogens, progesterone, relaxin, the prostaglandins, and oxytocin are all hormones concerned to a major degree with the onset and maintenance of parturition. Oestrogens, relaxin, and the prostaglandins are particularly involved with cervical ripening, while prostaglandins, progesterone and oxytocin are more involved in regulating myometrial contractility. Catecholamines may also have some regulatory function in relation to uterine contractions. Progesterone dominance during pregnancy is associated with a firm closed cervix, few myometrial gap junctions, low calcium levels in the cells, and a quiescent myometrium. At term, a change in the oestrogen/progesterone balance favours cervical ripening and increased uterine activity. Of particular importance at the level of the muscle cell are changes in the number of oxytocin receptors; a complex interaction between cAMP and phosphoinositide metabolism governs the intracellular level of calcium, thus regulating contractile activity.
The neuropeptide oxytocin, synthetized by magnocellular neurons in the hypothalamus, is well known for its peripheral action after it is released into the bloodstream from axons in the neurohypophysis. Less familiar is the notion that it is also released centrally to control the activity of oxytocinergic neurons themselves. When injected into the third ventricle of lactating rats during suckling, oxytocin increases the basal firing rate of oxytocinergic neurons as well as their activity at the time of each reflex milk ejection. On the other hand, centrally administered oxytocin engenders the neuronal-glial and synaptic plasticity characteristic of the oxytocin system when it is physiologically activated. From numerous in vivo and in vitro observations, it appears that central oxytocin is released in the hypothalamic nuclei themselves. For example, the use of push-pull cannulae inserted into one supraoptic nucleus of suckled rats shows that oxytocin is released inside the nucleus specifically during milk ejection. Moreover, ultrastructural immunocytochemistry reveals synaptic terminals in the supraoptic nucleus where both the pre- and postsynaptic elements are oxytocinergic. Nevertheless, the mechanism of the central release of the neuropeptide has still to be determined, especially in view of electrophysiological observations indicating that the release process in the hypothalamus is different from that within the neurohypophysis.
Neurons of the ventromedial hypothalamus (VMH) in female rats were electrophysiologically recorded via multibarrelled glass micropipettes and tested for responsiveness to vaginocervical stimulation as well as to a variety of other peripheral stimuli. A small percentage of VMH neurons were found to be specifically responsive to vaginocervical stimulation (type I response) in the ovariectomized animal. Priming the rats with estrogen (E) and progesterone (P) significantly increased the percentage of neurons responding specifically to vaginocervical stimulation but had no effect on the percentage of nonspecifically responding (type II) and nonresponding (type III) neurons. Pharmacological testing of all three types of VMH neurons was accomplished by iontophoretic application of luteinizing hormone releasing hormone (LHRH), prolactin (PRL), and dopamine (DA) to the cell membrane. PRL excited the majority of neurons tested and DA inhibited the majority of tested units regardless of the hormonal condition of the animal or the response elicited by vaginocervical and peripheral stimulation, LHRH, however, produced changes in firing rate which were related to the type of response evoked by vaginocervical stimulation. In E-P-primed animals, neurons which were specifically or nonspecifically affected by vaginocervical stimulation responded to LHRH in a similar manner whereas a different LHRH response profile was obtained in those neurons which were not effected by vaginocervical stimulation. The results indicate that an afferent pathway from the vaginocervix to the VMH exists, that E-P priming in some manner increases the probability that a VMH neuron will respond specifically to vaginocervical probing, and that the effect of LHRH is different in neurons responding to vaginocervical stimulation than in nonresponding neurons.
A positive correlation was observed between the midcycle elevation of estrogen (E) and the level of oxytocin- and estrogen-stimulated neurophysin (ESN), the protein carrier of oxytocin, in the plasma of five of six women. The time of the maximal level of E was associated with a level of oxytocin significantly greater than that in either the early follicular or late luteal phase (P less than 0.025). Likewise, the level of ESN at midcycle was greater than the level of ESN in the early follicular or late luteal phase (P less than 0.01). Other than states of lactation or pregnancy, this is the only described cyclic secretion of oxytocin in humans. Since oxytocin chronologically correlates with a rise in the level of E at midcycle, a role for oxytocin in ovulation may be considered.
This study assesses the influence of menstrual cycle phases and hormones on female sexual interest in both a nonclinical sample of volunteers (n = 18) and women who complained of premenstrual tension (n = 150). Women were assessed prospectively for two menstrual cycles with daily symptom charts. In addition mental status was assessed clinically and the Moos Menstrual Distress Questionnaire completed in the follicular and premenstrual phases. On the basis of these assessments women were assigned to subject groups. During the second cycle, daily 24-h urinary estrogens and urinary pregnanediol were determined. Sexual interest and feelings of well-being were recorded on a daily symptom rating chart. Sexual interest was found to be significantly higher in the follicular and ovulatory phases, than in the luteal, premenstrual, or menstrual phases. Sexual interest and feelings of well-being were correlated (R = 0.29). Sexual interest and feelings of well-being were not correlated with urinary estrogen or pregnanediol levels.
The presence of biologically active nerve growth factor (NGF) in the peripheral circulation of women during pregnancy, labour and lactation was investigated. Using a sensitive immunoenzymatic assay (ELISA), we found an approximately five-fold increase in plasma NGF levels during labour and lactation compared with the concentrations found at the term of gestation or in control healthy women. Since labour and lactation are characterized by activation of the hypothalamo-pituitary-adrenal axis and by high plasma levels of the neurohypophyseal hormone oxytocin, and since the intravenous injection of oxytocin in female rats causes a 176% increase in the hypothalamic levels of NGF, it is possible that the increased amount of circulating NGF is correlated with one or both of these events.
A search of the literature has been prepared to determine how oxytocin may affect sexual and reproductive in women. Many animal studies suggest that oxytocin induces a variety of reproductive behaviors, including grooming, sexual arousal, orgasm, gamete transport, nesting, birthing, and specific maternal behaviors such as breast-feeding and bonding between mother and infant. These actions are apparently facilitated by the 'priming' effect on certain cells by sex and steroid hormones - as the brief case report would also suggest. However, no adequate double-blind trial has confirmed the observations from this report in women. Only animal studies have been performed, albeit over a wide range of species. A variety of other causes and effects of sexual interest and arousal relating to oxytocin are considered, including some of those in males. More research is needed to clarify the role of oxytocin in human reproductive behaviors, including its potential 'aphrodisiac' or prosexual effect in women in the presence of the sex-steroid hormones.