J Infertil Reprod Biol, 2018, Volume 6, Issue 3, Pages: 9-15. https://doi.org/10.47277/JIRB/6(3)/9  
Histopathology and Biochemical Analysis of  
Pentazocine Effect on Ovary, Uterus, Adrenal  
Gland and Thyroid Gland of Female Albino  
Rats  
1
1
2
Sneha R. Banagar , Ravikumar J. Banagar and Sharangouda J. Patil *  
1
Department of Zoology, L. V. D. College, Raichur-584103, Karnataka, India  
2
Department of Life Sciences, School of Sciences, Garden City University, Bangalore, Karnataka, India  
Received: 11/06/2018  
Accepted: 09/08/2018  
Published: 20/09/2018  
Abstract  
Many drugs are known to interfere with the functions of CNS including hypothalamus there by modify the activity of  
hypophysis and gonads. Due to that many functions alters by them, such as the secretion and release of pituitary follicle  
stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PRL) are directly dependent on gonadotropic releasing  
hormones (GnRH). The effect of pentazocine on endocrine organs like ovary, uterus, thyroid and adrenal glands, there estrous  
cycle, gravimetrical changes, histological changes and biochemical changes has been evaluated. Three groups of healthy adult  
female albino rats having six rats in each group were taken. The rats of groups II and III were administered pentazocine at the  
dose level 0.5mg and 1.0mg/100g body weight respectively intraperitoneally/daily for 30 days. However, the rats of group I  
(
Control) were given saline alone.After the experimental periods, the rats were sacrificed and the histological study of ovary  
and uteri, thyroid and adrenal gland were performed. Body weight, estrous cycle, ovarian histometric elements of the follicles  
were non significant and histometrical changes of uterine parameters like diameter, thickness of myometrium and endometrium  
and surface epithelial cell height increased significantly. Biochemical changes of endocrine glands are parallel to the  
gravimetrical changes, the protein and glycogen contentsincreased significantly and reduced cholesterol content significantly  
with respective administration of both the dose level of pentazocine. Also, the gravimetric analysis of thyroid and adrenal  
gland increased significantly due to pentazocine administration. The study indicates that pentazocine has slightly stimulatory  
action on endocrine activities related to female reproduction.  
Keywords: Pentazocine, Endocrine glands, Estrous cycle, Ovary, Endometrium  
Introduction  
Pentazocine is an opioid with mixed agonist and  
antagonist properties (3). Gilbert and Martin (4) proposed  
that pentazocine is antagonist at µ-receptor and an agonist  
at both the Κ and δ-receptor. Bouchard and Quirion (5)  
have described the binding sites for pentazocine in the rat  
brain at various sites including thalamic and hypothalamic  
nuclei. Though pentazocine produces significantly greater  
analgesia among females than in males, no significant  
difference was observed in analgesic among females  
during different phases of the menstrual cycle (6, 7).  
Tifluadom, selective K-agonist elevates the 5-  
hydoxytryptophine (5-HT) and norepinephrine content,  
which have both facilitator and permissive role on LH  
secretion and ovulation (8, 9).  
The principle of central nervous system (CNS) influencing  
drugs are the anticonvulsants, antiparkinsonism, opioid  
and non-opioid analgesics, appetite suppressants,  
antiemetics, analgesics, antipyretics , certain stimulants,  
neutolectics, transquilizers sedatives and hypnotics.  
These drugs are known to interfere with the functions  
of CNS including hypothalamus there by modify the  
activity of hypophysis and gonads. The secretion and  
release of FSH, LH and PRL are directly dependent on  
(
GnRH). Therefore, the drugs which modify the functions  
of CNS may also effect the pituitary functions. As a result,  
the function of gonads may also be modified. Therefore,  
the structure and biological activities of some CNS  
influencing drugs, the actions of which modify the  
reproductive and endocrine activities is briefly  
summarized below. The effect of these drugs on female  
endocrine activities were undertaken.  
Material and Methods  
Animals  
Pentazocine was synthesized as part of deliberate effort to  
develop an effective analgesic with little or no abuse  
potential. The pharmacology of pentazocine has been  
reviewed by Brogden and associates (1). Pentazocine a  
benzomorphine derivative has the analgesic activity of the  
recemate mainly due to the 1-isomer (2).  
Healthy, sexually matured, regularly cycling, colony  
bred virgin female rats of Wistar strain (Rattus  
norvegicus) aged three months and weighing 150 -200 gm  
were purchased from National Institute of Nutrition,  
Hyderabad. The rats were housed in polypropylene cages  
measuring 12”x10”x8”, under well ventilated animal  
*Corresponding author: Dr. Sharangouda J. Patil, Associate Professor, Department of Life Sciences, School of Sciences,  
Garden City University, Bangalore, Karnataka, India, Email: shajapatil@gmail.com  
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J Infertil Reprod Biol, 2018, Volume 6, Issue 3, Pages: 9-15. https://doi.org/10.47277/JIRB/6(3)/9  
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.  
Experimental design  
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  
Gravimetric changes  
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  
morning.  
Biochemical changes  
Ethical issue  
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  
(Table 3).  
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.  
Autopsy schedule  
st  
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).  
evaluationof  
protein(12),  
glycogen(13)  
and  
cholesterollevel (14).  
Statistical analysis  
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,  
p<0.01 andp<0.001.  
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.  
Results  
Behavior  
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  
administration.  
Atretic follicles  
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).  
Mortality  
No mortality was observed in either control group or  
in the experimental group that received pentazocine.  
Corpus luteum  
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-  
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J Infertil Reprod Biol, 2018, Volume 6, Issue 3, Pages: 9-15. https://doi.org/10.47277/JIRB/6(3)/9  
Changes in the uterus  
Histometric changes of the uterus  
Uterine growth, biochemical contents, histopathology  
histometry observation were depends on dose of the  
pentozocine treatment.  
The histometric measurements of the uterus are  
parallel to that of protein content of uterus. The  
pentazocine treatment has increased the diameter of  
uterus, thickness of its myometrium, endometrium and  
height of the epithelial cell of endometrium. This increase  
was significant (P<0.05) only with its diameter. The  
changes were observed in all these parameters were dose  
dependent (Table 7; Figure 3-4).  
Gravimetric changes  
Both the doses of pentazocine stimulated the ovarian  
growth, as a result slight but non-significant increase in its  
weight was observed when compared with control (Table  
6
).  
Changes in the thyroid and adrenal glands  
Thyroid gland showed no significant change in its  
weight in pentazocine treated rats. The histological  
observations of thyroid in pentazocine treated rats,  
showed healthy follicles with normal secretion as same as  
that of normal rats. Pentazocine treatment, did not have  
any effect on adrenal gland as any significant change  
either in its weight or histological observation was not  
observation (Table 8; Figure 5-8).  
Biochemical changes  
Significant (P<0.05) reduction was seen in the  
cholesterol level of the uterus of pentazocine treated rats.  
The protein content increased significantly (P<0.05) and  
(
P<0.001) with respect to treatment of low and high dose  
of pentazocine. The glycogen content of the uterus treated  
with both the doses of pentazocine increased significantly  
(
P<0.05) (Table 6).  
Table 1: Effect of pentazocine on the body weight of female albino rats  
Groups  
Initial Body Weight  
Final Body Weight  
Percent Change  
Control (I)  
Group II  
Group II  
150.00 3.66  
168.30 4.80  
165.00 4.47  
160.00 3.32  
178.33 4.44  
175.00 4.27  
6.66  
6.68  
10.06  
M SE = Mean Standard error. *P<0.05, **P<0.01, ***P<0.001, when compared to saline treated rats  
Table 2: Effect of pentazocine on estrous cycle in female albino rats  
No. of  
cycles/rat  
5.40 0.21  
5.33 0.10  
5.33 0.26  
Length of cycles  
(days)  
5.41 0.30  
5.49 0.40  
5.32 0.96  
Duration of phases (days) / cycle  
Groups  
Estrus  
Metaestrus  
6.34 0.10  
6.30 0.24  
5.92 0.32  
Diestrus  
Proestrus  
4.41 0.31  
5.32 0.21  
5.64 0.30  
Control (I)  
Group II  
Group II  
6.81 0.19  
6.91 0.31  
7.21 0.43  
10.21 0.68  
10.00 0.45  
10.00 0.56  
M SE = Mean Standard error. *P<0.05, **P<0.01, ***P<0.001, when compared to saline treated rats  
Table 3: Effect of pentazocine on ovarian gravimetric and biochemical parameters in female albino rats  
Ovary mg/100gm body  
Groups  
Cholesterol g/mg  
Protein g/mg  
Glycogen g/mg  
weight  
Control (I)  
Group II  
Group II  
42.532.2  
47.40**2.09  
50.61**2.3  
4.16 0.23  
3.26*0.32  
2.50***0.17  
3.610.14  
4.02*0.21  
4.68***0.17  
1.890.09  
2.13**0.10  
2.22**0.12  
M SE = Mean Standard error. *P<0.05, **P<0.01, ***P<0.001, when compared to saline treated rats  
Table 4: Effect of pentazocine on ovarian kinetics in female albino rats  
Groups  
Developing follicles  
Antral follicles  
Graafian follicles  
Atretic follicles  
Corpus luteum  
Control (I)  
Group II  
Group II  
5.50 0.22  
5.92 0.20  
6.08* 0.26  
1.83 0.06  
2.05* 0.03  
2.09** 0.02  
1.83 0.22  
2.01** 0.18  
2.25*** 0.20  
1.89 0.09  
0.60** 0.05  
0.58** 0.04  
1.83 0.06  
2.05* 0.11  
2.09* 0.08  
M SE = Mean Standard error. *P<0.05, **P<0.01, ***P<0.001, when compared to saline treated rats  
Table 5: Effect of pentazocine on ovarian histometric elements of the follicles  
Developing  
follicles (m)  
9.06 0.48  
9.02 0.42  
Antral follicles  
(m)  
25.42 0.55  
26.21 0.48  
28.42 0.63  
Graafian follicles  
(m)  
33.48 0.24  
32.21 0.39  
34.29 0.38  
Atretic follicle  
(m)  
34.21 0.32  
35.21 0.42  
33.93 0.71  
Corpus luteum  
(m)  
48.21 0.57  
47.48 0.62  
50.48 0.60  
Groups  
Control (I)  
Group II  
Group II  
9.21 0.45  
M SE = Mean Standard error. *P<0.05, **P<0.01, ***P<0.001, when compared to saline treated rats  
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