house conditions (temperature: 28-31C). The rats were
deration for treatment of 30 days (Table 1).
fed with balanced diet as per CFTRI formula and tap water
ad libitum. They were maintained as per the principles of
laboratory animals care (NIH Publication No. 85-88, 1985
Changes in the estrous cycle
Control rats showed regular estrous cycle and there
length of cycles were observed similar to that of control
rats within 30 days. Pentazocine treatment has showed no
noticeable change either in the number of cycle or its
length. The different phases of estrous cycle like pro-
estrus, estrus, metaestrus, diestrus also were not different
when compared to that control rats (Table 2).
10). The animals were divided into five groups, each
consisting of six rats in each group and treated as follows.
The treatment was started when the animals were in
estrous phase. The group I received vehicle only (0.2ml
saline) and served as control. Group II and III received
pentazocine at dose level of 0.5 and 1.0mg for 100g body
weight in 0.2ml saline respectively. The treatment was
given for 30 days intraperitoneally between 10:00 to
The increase in the ovarian weight was seen in
pentazocine treated rats. This increase was significant
(P<0.01) with low dose and highly significant P<0.001)
with high dose of pentazocine administration (Table 3).
11:00AM to cover 6 regular estrous cycles and vaginal
smear from the experimental animals was observed every
Availability of pituitary gonadotropins is very
essential for the conversion of cholesterol into steroid
hormones in the ovary. Administration of pentazocine
caused reduction in the cholesterol level. Also significant
reduction in the cholesterol content was observed with low
dose (P<0.05) and high dose (P<0.001) of pentazocine
treatment. Ovarian growth and activities reflected through
its protein and glycogen content. Significant (P<0.05)
increase in the protein content was observed with low dose
and high dose (P<0.001) of pentazocine treatment.
Glycogen content of the ovary is increased significantly
(P<0.01) with the treatment of both doses of pentazocine
The experimental protocol was approved by the
Animal Ethical Committee in accordance with the
guidelines for care and use of laboratory animals prepared
by the Institutional Animal Ethics Committee
registered number 34800.
On day 31 , 24h after last treatment, all the animals from
each group sacrificed, the ovary, uterus, thyroid and
adrenal gland were dissected out, freed from extra
depositions of adherent tissue and weighed to the nearest
mg on an electronic balance. One side of ovaries, uterus,
thyroid and adrenal gland from each animals were fixed in
Bouin’s fluid for histological, cytological and
histometrical studies. The histometric measurement like
diameter of uterus, thickness of endometrium and
myometrium and height of endometrial epithelial cells
were made from randomly chosen 20 sections from each
group using ocular and stage micrometer(11) as well as
diameter of ovarian follicles were made.Ovaries and
uterus from other side were used for biochemical
Ovarian follicular kinetics
Administration of pentazocine caused non-significant
change in the ovarian follicular number and size (Table 4,
Figure 1 & 2).
Number and histometric changes in follicles
The number of developing follicles increased non-
significantly with low dose of pentazocine treatment,
whereas, it was almost significant (P<0.05) with high
dose. The number of antral follicles increased
significantly (P<0.01) with both the doses of pentazocine.
Also number of Graafian follicles increased significantly
with low and high doses of pentazocine (P<0.01 and
P<0.001 respectively) (Table 4).
All the values were statistically analysed by Student’s-
t’ test using SPSS(11.0.1.)(15). Data were expressed as
the Mean + S.E. Statistical significance was set at p<0.05,
The histometric changes of follicles were parallel with
that of number of follicles. Non-significant changes were
observed in the diameter of developing follicles, antral and
Graafian follicles with the treatment of low and high doses
of pentazocine treatment.
The rats which received the chronic treatment of
pentazocine were as active as the control rats and the total
intake of feed/day was not much altered due to drug
The number of atretic follicles decreased significantly
P<0.05) with both doses of pentazocine treatment and the
average diameter of atretic follicles of ovaries which
received low and high doses of pentazocine shows non-
significant change (Table 4).
No mortality was observed in either control group or
in the experimental group that received pentazocine.
The number of corpus lutea increased almost
significantly (P<0.05) with both doses of pentazocine and
they were as healthy as that of control without any
significant change in their diameter (Table 4).
Changes in the body weight
The body weight of the rats which received low or
high doses of pentazocine have showed slight increase in
the body weight which does not deserve significant consi-