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Vol 4 No 2, p 137-143
ABSTRACT
Ruminant Science December 2015 /137
GROSS MORPHOLOGICAL STUDIES ON HYPOTHALAMO-HYPOPHYSEAL-OVARIAN AXIS
OF INDIAN BUFFALO
Devendra Pathak* and Neelam Bansal
College of Veterinary and Animal Science, GADVASU, Ludhiana-141 004, Punjab, INDIA
Department of Veterinary Anatomy
*drdevendra@gmail.com
The present study was conducted to study the gross morphological and biometrical aspects of the hypothalamo-
hypophyseal-ovarian axis in Indian buffalo. The head for hypothalamus and hypophysis cerebri and ovary of 48 numbers
of buffaloes were utilized for the gross anatomical studies. The tissue samples were classified into four groups viz. prepubertal,
follicular, luteal phase and pregnant. The hypothalamus of buffalo was located ventral to the thalamus and extended from
optic chiasma to the mammillary body and formed the walls and the lower part of the third ventricle. The pituitary stalk
connected the ventral surface of the hypothalamus. The length of hypothalamus during prepubertal period was significantly
lower than pubertal period; however the length did not vary significantly during different phases of pubertal period. The
hypophysis cerebri was located in an oblique manner. The gland was composed of three visibly distinct areas viz.
adenohypophysis, neurohypophysis and pars intermedia. The infundibulum formed a swollen structure, median eminence
through which it joined the hypothalamus. The weight of the pituitary gland during prepubertal period was significantly
lower than during different pubertal period while it did not vary significantly during different phases of pubertal period.
The weight of the ovary varied greatly during different phase of cycle. The gross morphological and biometrical parameters
of components of hypothalamo-hypophyseal-ovarian axis of Indian buffaloes were established.
Key Words: Buffalo, gross morphology, hypothalamus, hypophysis cerebri, ovary.
The endocrine feedback loops that provide for
integrated function among the organs of the
hypothalamic-pituitary-gonadal (HPG) axis are
paramount to reproductive potential (Gharib et al,
1990). Fertility in mammals is initiated at puberty by
the pulsatile secretion of gonadotrophin releasing
hormone (GnRH) from hypothalamus which is involved
in the regulation of the reproductive axis. GnRH acts on
the anterior pituitary to release of the gonadotrophic
hormones, luteinizing hormone (LH), and follicle
stimulating hormone (FSH) which induce steroid
production and oogenesis in ovary. This present study
was aimed at detailed gross morphological and
biometrical study of components of hypothalamo-
hypophyseal ovarian axis during follicular and luteal
phases of estrous cycle in Indian buffalo.
Materials and Methods
The head and ovary of buffaloes (n=48) were
collected from New Delhi Municipal Corporation
Abattoir, Gajipur; MK Overseas Pvt Ltd, Dera Basi, local
abattoir at Bareilly and Teaching Veterinary Clinical
Complex, GADVASU, Ludhiana and were utilized for
the gross anatomical studies. The buffaloes were of four
groups (based on the history and age of the animal) viz.
prepubertal, follicular phase (presence of a dominant
follicle on the surface and absence of corpus luteum),
luteal phase (presence of a fully developed corpus
luteum), pregnant (presence of foetus in the uterus.
Grossly the length of hypothalamus (from optic chiasma
to posterior of mammillary body) was measured. The
weight of pituitary gland and weights of left and right
ovaries of each animal were recorded. The data was
analysed by analysis of variance (ANOVA) to find out
significant differences between the four groups and pair
of groups were analysed with student’s ‘t’ test for
significant differences between the groups and data was
considered significant when p-value was less than 0.05
(p<0.05).
Results and Discussion
Hypothalamus
The hypothalamus of buffalo was located ventral
to the thalamus. The anterior boundary of the
hypothalamus was bounded by optic chiasma and
posteriorly it extended just behind the mammillary body
(Figs 1, 2, 3) as described earlier by Bleier et al (1979) in
rats, Pathak (2001) in goat, Konig and Liebich (2004)
in domestic animals and Paramsivan (2007) in sheep who
stated that the hypothalamus was made up of concealed
rostral part and the caudal part formed by the tuber
cinereum and mammillary bodies in most of the
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Fig 1. Sagital section of buffalo skull showing brain with
thalamus (TH), hypothalamus (HT), hypothalamic
sulcus (arrow), optic nerve (O), pituitary (PG)
present in sella tursica in sphenoid bone (SB).
Fig 2. Sagittal section og buffalo hypothalamo-pituitary
unit showing thalamus (TH), hypothalamus (line
drawing), hypothalamic sulcus (arrow), optic nerve
(O), mammillary body (MB), Pituitary (PG).
Fig 3. Ventral surface of the buffalo brain showing margin
of hypothalamus with optic chiasma (OC), point
of attachment of pituitary (arrow), mammillary
body (MB).
Fig 4. Coronal section of buffalo hypothalamus showing
thalamus (TH), hypothalamus (line drawing),
third ventricle (TV arrow).
Fig 5. Photograph showing connection of hypothalamus
(HT) and pituitary (arrow), thalamus (TH),
mammillary body (MB), infundibulum (INF),
pars distalis (PD), pars nervosa (PN).
Fig 6. Superior view of buffalo skull base showing supra
cellar (SC) portion of the pituitary gland visible
through the diaphragmatic aperture (arrow), optic
nerve (ON).
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Fig 7. Pituitary of buffalo with various shapes Fig 8. Sagittal section of pituitary showing pars distalis
(PD), pars intermedia (PI), pars nervosa (PN) and
hypophyseal cleft (arrow).
Fig 9.Upper portion of pituitary showing pars
infundibulum (INF), median eminence (ME),
pars distalis (PD), pars nervosa (PN).
Fig 10. Pituitary of buffalo showing superior hypophyseal
artery (arrow), sagittal section showing two
distinct portion of pituitary, pars distalis (PD),
pars nervosa (PN) and pituitary stalk.
Fig 11. Photograph of buffalo ovary during period (11-A) and ovary with smooth and glistening surface with fluid
filled follicles (F) during follicular phase of estrous cycle (11-B) and nodular ovary during follicular phase
with elevated follicular structures on surface (arrow) (11-C).
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mammals. It formed the walls and the lower part
of the third ventricle (Fig 4).
The dorsal border was marked by a horizontal
shallow groove called the hypothalamic sulcus which
separated it from the thalamus (Figs 1, 2). The pituitary
stalk connected the ventral surface of hypothalamus to
the pituitary gland in between the optic chiasma and
mammillary body. The anterior border of the
hypothalamus was the preoptic area which was bounded
rostrally by the anterior commissure and optic chiasma.
While the posterior border was marked with tegmentum
of the mid brain superiorly and mammillary body
inferiorly. These observations are in concurrence with the
findings of Pathak (2001) in goat and Paramsivan (2007)
who found similar boundaries of hypothalamus in sheep.
Konig and Liebich (2004) described the hypothalamus
in domestic animals being consisted of optic chiasma
rostrally, mammilary body caudally and tuber cinereum
in between. Fink et al (2012) described hypothalamus
in humans, being bound rostrally by optic chiasma,
caudally by mammillary body, laterally by optic tracts
and dorsally by the thalamus
The length of hypothalamaus (distance from optic
chiasma to mammillary body) was 1.62±0.046 cm,
2.16±0.069 cm, 2.20±0.066 cm and 2.21±0.072 cm
during prepubertal, follicular phase, luteal phase and
pregnancy, respectively. The length of hypothalamus
during prepubertal period was significantly lower than
pubertal period; however the length did not vary
significantly during different phases of pubertal period.
The length may be correlated with development of
hypothalamus with influence of hormones from
hypothalamo-hypophyseal-ovarian axis.
Hypophysis Cerebri
The hypophysis cerebri was located in the sella
turcica of the sphenoid bone just posterior to optic
chiasma in an oblique manner. The gland was connected
to the brain by hypophyseal stalk (Figs 2, 5). The gland
was covered by the fold of dura mater called diaphragm
sellae, which formed the roof of the sella turcica. It
covered the entire pituitary gland except for a small
aperture in the centre, through which the infundibular
stalk passed rostrally and dorsally and formed suprasellar
portion of the gland (Fig 6).
The gland varied in its shape and appeared as oval,
irregularly triangular or boat shaped with a shallow
depression in the dorsal surface (Fig 7). Earlier authors
described it an elongated in buffalo heifers and thick
and oval in the adult buffaloes (Muhammad and Khan,
1984). Pituitary gland of Gaddi goat was elongated and
boat shaped (Pathak and Bhardwaj, 2004). In the sagittal
section of the gland, there was three visibly distinct areas
viz. adenohypophysis, neurohypophysis and pars
intermedia (Fig 8). The adenohypophysis was located
rostrally while neurohypophysis was seen posteriorly and
pars intermedia in between the two. The pars intermedia
were separated from the pars distalis by a narrow intra
glandular cleft. The gland was connected to the ventral
surface of the hypothalamus between the optic chiasma
rostrally and the mammillary body caudally by the
infundibular stalk. The infundibulum formed a swollen
structure, median eminence through which it joined the
hypothalamus (Fig 9). The superior hypophyseal artery
entered the pituitary gland at the level of pituitary stalk
area to form primary portal plexus for the vascular supply
to the gland (Fig 10).
The average weight of the pituitary gland of buffalo
was 0.62±0.02 g, 1.86±0.09 g, 1.95±0.11 g and
1.77±0.07 g during prepubertal period, follicular phase,
luteal phase and pregnant animals respectively. The
weight of the pituitary gland during prepubertal period
was significantly lower than during different pubertal
period while it did not vary significantly during different
phases of pubertal period. It varied according to the
reproductive stage of the animal. The lowest weight of
pituitary gland during prepubertal period corresponds
to the least length of hypothalamus during the same
period. It may be postulated that as the hypothalamus
enlarges it helps in the growth of pituitary by release of
releasing hormones. Increase in the weight of pituitary
gland in camels with age was also reported (Jaspal et al,
2011). However there was no significant difference
between the weights of pituitary gland in different
pubertal groups which suggested that the hormonal
variation in the releasing hormones does not impact the
mass of the pituitary glands. Comparable morphological
observations were recorded in the buffalo pituitary gland
and the weight of pituitary gland during estrous cycle
was found larger than that during the anoestrous period
(Akhtar et al, 2012).
Ovary
Buffalo ovaries were paired, oval shaped organ
attached to meso-ovarium, located in pelvic cavity on
either side of uterus. The surfaces of ovaries varied
according to the reproductive stage depending upon the
Fig 12. Photograph of buffalo ovary during luteal phase of estrous cycle: 12-A corpus haemorrhagicum (CH); 12-B
corpus luteum (CL) of enclosed type and enclosed CL seen in cross section (12-D); 12-C corpus luteum elevated
on the surface; 12-E corpus luteum in cross section with distinct neck (arrow head); 12-F corpus albicans (CA).
Fig 13. Photograph of ovary of pregnant buffalo showing luteal stroma covering almost whole of the ovary (13-A)
with very few follicular structures (F) in the peripheral portion in the cross section of ovary (13-B).
Ruminant Science December 2015 /141
protrusion of follicles or corpus luteum. Ovaries of
prepubertal buffaloes were smooth and no follicular or
luteal structures were seen on the surface (Fig 11-A).
During the follicular phase of estrous cycle, ovaries were
either smooth, with one or more well developed glistering
membrane follicles or nodular in appearance with few
protruded follicles (Figs 11-B, 11-C). During the luteal
phase of the estrous cycle, the ovarian surface had a small
red coloured structure protruding over the surface (corpus
haemorrhagicum) which increased in size with age (Fig
12-A) till the formation of fully developed corpus luteum.
The corpus haemorrhagicum had a bright red small crown
on the surface which became brownish red and fleshy as
the size increased. The corpus luteum was either fully
embedded in the ovarian stroma (Fig 12-B) or was
protruded on the surface with a well-marked neck
separating the protruded crown from the ovary (Fig 12-
C). The sagittal section of both these types of corpus
luteum revealed that in previous type of CL most of the
part was embedded in the ovary (Fig 12-D) while in the
later a small part was present in the ovary while major
part was protruded on the surface (Fig 12-E). The copus
luteum transformed into copus albicans (Fig 12-F) which
was observed in non-pregnant animals. During the
pregnancy, the ovary of buffalo appeared as if whole of
the ovary has transformed into a copus luteum (Fig 13-
B) and the cut section was yellowish in colour and the
luteal tissue occupied most of the ovarian stroma with
the peripheral part consisted of other structures (Fig 13-
B). The mesovarium transmitted the blood vessels,
lymphatics and nerves through the hilus of the ovary.
The ovarian shape and surface morphology varied
according to the stage of reproductive cycle and was based
on the presence of dominant structures in that particular
stage. Similar surface morphology has been described
earlier by various authors in Indian buffaloes (Bansal et
al, 2004; Rakesh et al, 2013) and Iranian buffaloes
(Hasanzadeh and Sadeghinezad, 2012).
The weight of the ovary varied greatly during
different phase of cycle because of the presence of different
sized follicles and corpus luteum. The average weight of
the left ovaries was 0.76±0.05 g and of right ovaries was
0.80±0.10 g during prepubertal period. The average
weight of left and right ovaries were 2.96±0.13 g and
2.90±0.11 g during follicular phase, 3.39±0.15 g and
3.13±0.19 g during luteal phase and 3.91±0.17 g and
4.12±0.15 g in pregnant buffaloes. The right ovary was
found to be larger than the left ovary. The mean weights
of left and right ovaries were comparable with weights
described by (Bansal et al, 2004) in Indian buffaloes.
The right ovary was larger than the left ovary which was
in consonance with the findings of in Red Bororo cattle
(Jaji et al, 2012). This might be due to the reach more
amount of estrogen hormone to right ovary than the left
through differential blood supply and right ovary might
be functionally more active.
Acknowledgement
Authors are thankful to the In-charge slaughter houses
for allowing us to collect tissue samples for the present
study.
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