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Abstract

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 w.blaicher@akh-wien.ac.at
ABC
Fax + 41 61 306 12 34
E-Mail karger@karger.ch
www.karger.com
© 1999 S. Karger AG, Basel
0378–7346/99/0472–0125$17.50/0
Accessible online at:
http://BioMedNet.com /karger
Key Words
Oxytocin W Human W Sexual arousal
Abstract
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
behavior.
Introduction
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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1
126
Gynecol Obstet Invest 1999;47:125–126
Blaicher/Gruber/Bieglmayer/Blaicher/
Knogler/Huber
Table 1.
OXY values (in pg/ml) at baseline, exactly 1 and 5 min after
orgasm in 12 female volunteers
Subject
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.
Results
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).
Discussion
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.
References
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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. ...
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... 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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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.