Effect of blocking oestrogen synthesis with a new generation aromatase inhibitor CGS 16949A on follicular maturation induced by pregnant mare serum gonadotrophin in the immature rat

1994 ◽  
Vol 142 (3) ◽  
pp. 563-570 ◽  
Author(s):  
N Selvaraj ◽  
G Shetty ◽  
K Vijayalakshmi ◽  
A S Bhatnagar ◽  
N R Moudgal
Keyword(s):  
Aromatase Inhibitor ◽  
Granulosa Cells ◽  
Follicular Development ◽  
Treated Group ◽  
Female Rats ◽  
Percentage Increase ◽  
Follicular Maturation ◽  
Significant Difference ◽  
New Generation ◽  
Pregnant Mare Serum Gonadotrophin

Abstract While the endocrine role of oestrogen is well established, its function in follicular maturation as an autocrine or paracrine regulator is less well understood. This study was designed to delineate the requirement of oestrogen for follicular development in immature rats. Exogenous gonadotrophin (25 IU pregnant mare serum gonadotrophin (PMSG) per rat) was administered to 21- to 23-day old female rats to induce follicular growth and development. In the experimental animals, synthesis of oestrogen was blocked by implanting an Alzet pump containing the aromatase inhibitor (AI) CGS 16949A (fadrozole hydrochloride; 50 μg/rat per day). The treatment resulted in blockade of the PMSG induced increase in both serum and intrafollicular oestrogen (>95%), thus leading to an inhibition in uterine weight increment. Compared with the controls, ovarian weight increased markedly in both the PMSG (295%)- and PMSG+AI (216%)-primed animals. There was no significant difference in either the proliferative capabilities of the ovarian granulosa cells or their responsiveness to human chorionic gonadotrophin (hCG; 200 pg/ml) and ovine FSH (20 ng/ml) between the PMSG- and PMSG+AI-treated groups. Histological examination of the ovary, however, indicated a decrease in the number of healthy antral follicles in the AI-treated group compared with the PMSG-primed animals but both the groups showed a percentage increase over the controls (PMSG, 225; PMSG+AI, 158). The responsiveness of the animals to an ovulatory dose of hCG was drastically reduced (>80% inhibition of ovulation) in the oestrogen-deprived animals; this could be overriden by exogenous administration of oestrogen. In conclusion, although blocking oestrogen synthesis in the PMSG-primed rat does not seem to alter the functional properties of the isolated granulosa cells in vitro there appears to be an effect on the number of follicles which complete maturation and are able to ovulate in vivo. Journal of Endocrinology (1994) 142, 563–570

scholarly journals Heat stress diminishes gonadotropin receptor expression and enhances susceptibility to apoptosis of rat granulosa cells

Reproduction ◽  
2005 ◽  
Vol 129 (4) ◽  
pp. 463-472 ◽  
Author(s):  
Takashi Shimizu ◽  
Izumi Ohshima ◽  
Manabu Ozawa ◽  
Satoko Takahashi ◽  
Atsushi Tajima ◽  
...  
Keyword(s):  
Heat Stress ◽  
Granulosa Cells ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Receptor Expression ◽  
Female Rats ◽  
Aromatase Activity ◽  
Mrna Levels ◽  
Gonadotropin Receptor ◽  
Estradiol Levels

Heat stress inhibits ovarian follicular development in mammalian species. We hypothesized that heat stress inhibits the function of follicular granulosa cells and suppresses follicular development. To test this, immature female rats were injected with pregnant mare serum gonadotropin (PMSG) at 48 h after the start of temperature treatment (control: 25 °C, 50% RH; heat stress: 35 °C, 70% Relative Humidity). The ovaries and granulosa cells of follicles at different developmental stages were analyzed for gonadotropin receptor levels and aromatase activity; estradiol levels were measured in follicular fluid. Before injection, heat stress diminished only the amount of FSH receptor on granulosa cells of antral follicles. During PMSG-stimulated follicular development, heat stress strongly inhibited gonadotropin receptor levels and aromatase activity in granulosa cells, and estradiol levels in the follicular fluid of early antral, antral and preovulatory follicles. To examine apoptosis and mRNA levels of bcl-2 and bax in granulosa cells, follicles harvested 48 h after PMSG injection were cultured in serum-free conditions. Heat-stressed granulosa cells showed a time-dependent increase in apoptosis. The bcl-2 mRNA levels were similar in control and heat-stressed granulosa cells; bax mRNA levels were increased in heat-stressed granulosa cells. According to these results, heat stress inhibits expression of gonadotropin receptors in granulosa cells and attenuates estrogenic activity of growing follicles, granulosa cells of heat-stressed follicles are susceptible to apoptosis, and the bcl2/bax system is not associated with heat-stress-induced apoptosis of granulosa cells. Our study suggests that decreased numbers and function of granulosa cells may cause ovarian dysfunction in domestic animals in summer.

Toxic Effects of Aluminium on Female Reproductive System in Presence of Ethanol Coexposure

2021 ◽  
pp. 3809-3815
Author(s):  
Buddhadeb Ghosh ◽  
Ravi Kant Sharma ◽  
Suman Yadav ◽  
Ankita Randev
Keyword(s):  
Body Weight ◽  
Granulosa Cells ◽  
Reproductive Toxicity ◽  
Concomitant Administration ◽  
Exposure Period ◽  
Treated Group ◽  
Female Rats ◽  
Corpora Lutea ◽  
Combined Administration ◽  
Increasing Trends

Both aluminium and ethanol are pro-oxidants and toxic. Uncontrolled use of aluminium and increasing trends of ethanol consumption in India increased the chance of coexposure to aluminium and ethanol. There are possibilities, that both of them follow common mechanisms to produce reproductive toxicity. The present study was planned to identify the effects of aluminium administration on the microscopic structure of ovary and to clarify any possible protection conferred by the concomitant administration of ethanol. Sixteen female rats divided into one control and three experimental groups exposed to aluminium (4.2mg/kg body weight) and ethanol (1gm/kg body weight) for 3 months. After the exposure period, ovaries were processed for light microscopic examination. Ovary showed significant atretic follicles with degenerated ova and vacuolation. Rupture of zona pellucida in oocyte seen in aluminium treated animals. Ethanol treated group showing absence of growing follicles, increased large corpora lutea. Dilated and congested vessels were observed in the growing follicle. The effects of combined administration of aluminium and ethanol treated groups showed with acute degeneration of growing follicles, with desquamation of pyknotic granulosa cells and degenerated oocyte. Multiple vacuoles of degenerated granulosa cells with dilated congested vessels and edema seen. Hyaline material seen inside the degenerating follicles. It has been suggested that the ethanol induced augmentation of impacts of aluminium on the Ovary.

ANTERIOR PITUITARY SENSITIVITY IN IMMATURE FEMALE RATS STIMULATED WITH GONADOTROPHIN RELEASING HORMONE IN VIVO: EFFECT OF PRIMING WITH OESTROGEN, PREGNANT MARE SERUM GONADOTROPHIN OR BRAIN LESION

1977 ◽  
Vol 74 (1) ◽  
pp. 99-109 ◽  
Author(s):  
D. DE ZIEGLER ◽  
M. WILKINSON ◽  
DANIELLE CASSARD ◽  
K. B. RUF
Keyword(s):  
Brain Lesion ◽  
Treated Group ◽  
Female Rats ◽  
Similar Degree ◽  
Female Rat ◽  
Immature Female ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Pregnant Mare Serum Gonadotrophin

An investigation of pituitary sensitivity, assessed in terms of increments in plasma LH and FSH concentrations, to stimulation with one or two injections of gonadotrophin releasing hormone (GnRH) was carried out on 26-day-old immature female rats which had received one of the following priming treatments: 10 μg oestradiol benzoate (OB) as a single injection on day 23 or day 25, or on both days; 10 i.u. pregnant mare serum gonadotrophin (PMSG) on day 24; an electrochemical brain lesion placed in the mediobasal hypothalamus on day 23; control animals received either vehicle alone or a sham lesion. Pituitary sensitivity assessed at 10.00 h on day 26, after one or two injections of GnRH (100 ng/100 g body weight, s.c.), was enhanced to a similar degree in the three groups treated with OB in terms of LH (P < 0-01). The FSH response also increased after OB treatment but was not statistically significant. In contrast, 48 h after the injection of PMSG (i.e. when the rats were in a 'pro-oestrous-like' condition) pituitary sensitivity in terms of both LH and FSH dropped sharply (P < 0·001). In lesioned animals, pituitary sensitivity to one injection of GnRH was unchanged. A second GnRH injection administered after a 60 min interval induced a slightly larger LH response in control animals. In contrast, the ratio of the second response to the first increased in animals treated with PMSG, despite the state of overall decrease in sensitivity, being 4·5:1 in PMSG-treated rats versus 1·4:1 in controls. In a second set of experiments, we investigated the variation of pituitary sensitivity in conjunction with an experimentally induced gonadotrophin surge. In animals treated with OB on day 23 and with 1 mg progesterone at 12·00 h on day 26, pituitary sensitivity was increased at both 14.00 and 17.00 h as compared with that in the day 23 OB-treated group at 10.00 h. The PMSG-treated animals maintained their state of decreased responsiveness at 14.00 h, but exhibited increased pituitary sensitivity at the time of the gonadotrophin surge (17.00 h). These results show that OB increases pituitary sensitivity to GnRH in 26-day-old female rats and that the induction of a gonadotrophin surge further increases this sensitivity. In contrast, PMSG-treated rats displayed a state of decreased responsiveness 48 and 52 h, but not 55 h, after the injection. Pituitary sensitivity on the second day after PMSG treatment thus clearly differs from that observed during pro-oestrus in the adult cyclic female rat.

Internalization of receptor-bound human chorionic gonadotrophin in preovulatory rat granulosa cells in vivo

1983 ◽  
Vol 103 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Kalle Jääkeläinen ◽  
Seppo Markkanen ◽  
Hannu Rajaniemi
Keyword(s):  
Plasma Membrane ◽  
Granulosa Cells ◽  
Subcellular Distribution ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
Electron Microscope Autoradiography ◽  
Silver Grains ◽  
Pregnant Mare Serum Gonadotrophin

Abstract. The subcellular distribution of 125I-labelled human chorionic gonadotrophin (hCG) in preovulatory rat granulosa cells was studied in vivo. Pregnant mare serum gonadotrophin-pretreated immature female rats received an iv injection of [125I]hCG a few hours before the endogenous preovulatory gonadotrophin surge. The animals were killed at 2 or 6 h after the [125I]hCG injections. Light microscope autoradiographs showed that the mural granulosa cells of large follicles were the most highly labelled cells in the ovaries. Electron microscope autoradiography was used to study the subcellular distribution of radioactivity in the mural granulosa cells. At 2 h 45% of the counted silver grains were associated with the plasma membrane and 10% with the lysosomes, at 6 h the values were 51% and 9%, respectively. The distribution of the observed silver grains was compared with the generated expected source to grain pairs by computerized linear multiple regression analysis. The magnitudes of the regression coefficients revealed that the plasma membrane and the lysosomes were the only specifically 125I-labelled organelles, that a few radioactive molecules were located diffusely over the cytoplasm at 2 h and that the 125I-radioactivity of the nuclei was negligible. The present results suggest that preovulatory rat granulosa cells are in vivo able to internalize into lysosomes [125I]hCG initially bound to LH/hCG receptors of the plasma membrane.

scholarly journals Concanavalin-A Induces Granulosa Cell Death and Inhibits FSH-Mediated Follicular Growth and Ovarian Maturation in Female Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (5) ◽  
pp. 1885-1896 ◽  
Author(s):  
Ethel V. Velasquez ◽  
Mariana Ríos ◽  
María Elena Ortiz ◽  
Carlos Lizama ◽  
Elizabeth Nuñez ◽  
...  
Keyword(s):  
Cell Death ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Concanavalin A ◽  
Ex Vivo ◽  
Female Rats ◽  
Carbohydrate Binding ◽  
Con A ◽  
Follicular Maturation

Abstract Reproductive success stems from a finely regulated balance between follicular maturation and atresia, in which the role of carbohydrate structure is poorly understood. Here, we describe for the first time a fraction of purified recombinant human FSH that is capable of bringing about the cell death of granulosa cells and preventing follicular maturation in a rat model. Further analysis by mass spectrometry revealed the presence of the lectin Concanavalin-A (Con-A) within this fraction of recombinant FSH. Using both the fractionated FSH and Con-A, the observed cell death was predominantly located to the granulosa cells. Ex vivo culture of rat follicles demonstrated that follicle degeneration occurred and resulted in the release of a denuded and deteriorated oocyte. Moreover, in vivo experiments confirmed an increase in atresia and a corresponding reduction confined to follicle in early antral stage. As a mechanism of action, Con-A reduces ovarian proliferation, Von Willebrand staining, and angiogenesis. Based on the observation that Con-A may induce granulosa cell death followed by follicle death, our results further demonstrate that follicular carbohydrate moiety is changing under the influence of FSH, which may allow a carbohydrate-binding lectin to increase granulosa cell death. The physiological consequences of circulating lectin-like molecules remain to be determined. However, our results suggest a potential exploitation of carbohydrate binding in fertility and ovarian cancer treatment. This work may shed light on a key role of carbohydrates in the still obscure physiological process of follicular selection and atresia.

SERUM GONADOTROPHINS AND FOLLICULAR DEVELOPMENT IN IMMATURE RATS AFTER EARLY ANDROGEN ADMINISTRATION

1976 ◽  
Vol 68 (3) ◽  
pp. 461-468 ◽  
Author(s):  
J. TH. J. UILENBROEK ◽  
E. ARENDSEN DE WOLFF-EXALTO ◽  
M. A. BLANKENSTEIN
Keyword(s):  
Testosterone Propionate ◽  
Follicle Stimulating Hormone ◽  
Follicular Development ◽  
Female Rats ◽  
Vaginal Opening ◽  
Follicular Growth ◽  
Antral Follicles ◽  
Follicular Maturation ◽  
Immature Rats ◽  
Plasma Oestradiol

SUMMARY Follicular development and serum gonadotrophin levels were studied in female rats after neonatal androgen administration. After injection of 1250 μg testosterone propionate (TP) on day 5 after birth the composition of the follicular population was altered: at nearly all ages the number of pre-antral follicles (follicular volume 2–20 × 105 μm3) was lower than in oil-treated rats, in some cases the number of small antral follicles (21–249 × 105 μm3) was also lower. Furthermore levels of serum follicle-stimulating hormone and luteinizing hormone were decreased from day 7 to day 20 suggesting that the high gonadotrophin levels before day 20 are of importance for normal follicular development. In contrast, final follicular maturation in TP-treated rats was enhanced; at day 35 more large antral follicles (follicular volume ≥ 500 × 105μm3) were present in TP-treated rats than in oil-treated rats. The presence of more large antral follicles was accompanied by higher plasma oestradiol concentrations, higher uterine weights and advanced vaginal opening. These results demonstrate an inhibition of normal follicular growth and an acceleration of ovarian maturation after neonatal androgen administration.

Early effects of tobacco smoke exposure on vascular dynamics in the microcirculation

1975 ◽  
Vol 39 (1) ◽  
pp. 119-123 ◽  
Author(s):  
D. Richardson ◽  
F. Coates ◽  
R. Morton
Keyword(s):  
Tobacco Smoke ◽  
Capillary Flow ◽  
Treated Group ◽  
Smoke Exposure ◽  
Female Rats ◽  
Tobacco Smoke Exposure ◽  
Arterial Blood ◽  
Significant Difference ◽  
Early Effects ◽  
Mesenteric Microcirculation

The purpose of these studies is to examine the early effects of chronic tobacco smoke exposure on vascular dynamics in the mesenteric microcirculation. Female rats were exposed daily to tobacco smoke from five reference cigarettes for a period of 2 mo. At the end of this period the smoke-treated rats had gained 12 g less than sham-treated controls, and arterial blood pressure in the smoke-treated animals was slightly less than pressure in the sham-treated animals. These are characteristic effects of tobacco smoke exposure on rats. Following the treatment period, red blood cell (RBC) velocity in single mesenteric capillaries and microvascular pressures in arterioles and venules were measured in accordance to established methods. There was no significant difference in pressure distribution on the arterial side of the mesenteric vascular network, but pressure in the venules of the smoke-treated animals was significantly higher than that of the sham-treated group. In association with the higher venular pressure in the smoke-treated animals, capillary RBC velocity (an index of capillary flow) was significantly lower. The reduction in velocity was in proportion to the decrease in pressure drop (arteriole-venule) across the capillary network.

Developmental regulation of androgen receptor in rat ovary

1995 ◽  
Vol 145 (3) ◽  
pp. 535-543 ◽  
Author(s):  
M Tetsuka ◽  
P F Whitelaw ◽  
W J Bremner ◽  
M R Millar ◽  
C D Smyth ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Mrna Expression ◽  
Granulosa Cells ◽  
Developmental Regulation ◽  
Follicular Development ◽  
Female Rats ◽  
Northern Analysis ◽  
Control Value ◽  
Immature Rats ◽  
Rat Ovary

Abstract Androgen receptor (AR) distribution and developmental regulation in the rat ovary were examined by semiquantitative immunohistochemistry. Ovarian AR mRNA levels were also determined by Northern analysis of total RNA and compared with the levels of cytochrome P450aromatase (P450arom), an established marker of preovulatory follicular maturity. Hypophysectomized immature female rats were treated with recombinant human (rh)-FSH and/or rh-LH, or human menopausal gonadotrophin (HMG). AR was predominately located in granulosa cells. There was no indication of specific AR immunoreactivity in thecal cells, but scattered stromal cells did stain positively. In control and LH-treated ovaries, only small preantral/early antral follicles were present. Granulosa cells in these follicles showed intense AR immunostaining. Treatment with FSH, FSH and LH or HMG stimulated varying degrees of preovulatory follicular development. In these follicles, the intensity of AR immunostaining progressively declined as follicular development progressed. In intact immature rats treated with FSH, the abundance of ovarian AR mRNA was significantly decreased to 35% of the control value while combined treatment of FSH and LH resulted in further down-regulation of AR mRNA expression to 17% of the control value. A decrease in the abundance of AR mRNA was accompanied by a simultaneous increase in the abundance of P450arom mRNA. Similar results were obtained in hypophysectomized immature rats treated with FSH and LH, suggesting an inverse relationship between AR mRNA expression and granulosa cell maturity. These results suggest that (1) the AR is most abundant in the granulosa cells of rat ovaries and (2) the expression of AR and its mRNA are developmentally regulated, being down-regulated during FSH-stimulated preovulatory follicular development. Journal of Endocrinology (1995) 145, 535–543

scholarly journals Relationship between FoxO1 protein levels and follicular development, atresia, and luteinization in the rat ovary

2003 ◽  
Vol 179 (2) ◽  
pp. 195-203 ◽  
Author(s):  
F Shi ◽  
PS LaPolt
Keyword(s):  
Chorionic Gonadotropin ◽  
Granulosa Cells ◽  
Cell Cycle Progression ◽  
Follicular Development ◽  
Immunohistochemical Analysis ◽  
Female Rats ◽  
Corpora Lutea ◽  
Protein Levels ◽  
Physiological Processes ◽  
Preovulatory Follicles

FoxO1 is a transcription factor implicated in a growing number of physiological processes, including apoptosis, cell cycle progression, and insulin signaling. Recent findings indicate that FSH and growth factors influence ovarian functions in part through regulation of FoxO1. The present study utilized immunohistochemical analysis to determine the ovarian localization and regulation of FoxO1 protein levels in neonatal rats, immature rats during gonadotropin-induced follicular development, ovulation, and luteinization, and in spontaneously developing ovarian cysts of aging rats. In postnatal rats, FoxO1 immunoreactivity was very faint in ovaries of 5- and 10-day-old females. In contrast, strong immunoreactivity was observed in granulosa cells of larger developing follicles at 25 days of age. To stimulate follicle development, immature female rats received equine chorionic gonadotropin (eCG) followed 52 h later by an ovulatory dose of human chorionic gonadotropin (hCG). Prior to gonadotropin treatment, moderate FoxO1 immunoreactivity was observed in granulosa cells of small follicles. Subsequently, treatment with eCG markedly decreased FoxO1 protein levels in granulosa cells of healthy antral and preovulatory follicles. Interestingly, FoxO1 staining was observed in cumulus and antral, but not mural granulosa cells of preovulatory follicles. Induction of ovulation and luteinization with hCG further decreased ovarian FoxO1 levels, with no staining evident in corpora lutea. At all time points, the most intensive FoxO1 staining was observed in granulosa cells of atretic follicles, with predominantly nuclear localization. Similarly, while FoxO1 levels were low in granulosa cells of preovulatory follicles in proestrous rats, FoxO1 staining was intense in granulosa cells of spontaneously developing cystic follicles in aged, acyclic females. Together, these findings indicate that FoxO1 is expressed in a regulated, cell-specific manner during ovarian follicular development, atresia and luteinization, suggesting roles in these physiological processes.

Steroidogenesis and cAMP production in isolated avian granulosa cells during follicular maturation: Lack of positive correlation

1986 ◽  
Vol 113 (2) ◽  
pp. 289-297 ◽  
Author(s):  
Elikplimi K. Asem ◽  
Frank Hertelendy
Keyword(s):  
Adenylate Cyclase ◽  
Granulosa Cells ◽  
Follicular Development ◽  
Intrinsic Activity ◽  
Camp Production ◽  
Follicular Maturation ◽  
The Third ◽  
Preovulatory Follicles ◽  
Maturational Stage ◽  
Camp System

Abstract. Luteinizing hormone- and forskolin-induced acute steroidogenesis and cAMP production were studied in dispersed chicken granulosa cells in relation to follicular maturation. Cells isolated from the 6 largest preovulatory follicles (F1-F6) were used in this study. Basal steroidogenic activity increased with progressive maturation of the follicle without a corresponding rise in basal cAMP production. Both LH- and forskolinpromoted progesterone production was directly correlated with the maturational stage of the follicle and the dose of the agonists. On the other hand, LH caused the greatest increase in cAMP production in the third and fourth largest preovulatory follicles (F3-F4), whereas forskolin-stimulated cAMP accumulation was maximal in the least mature granulosa cells (F5-F6). Thereafter it decreased in proportion with follicular development. It is concluded that LH-induced acute steroidogenesis in chicken granulosa cells is not positively correlated with cAMP production during the last few days of follicular maturation. Therefore the steroidogenic responsiveness of granulosa cells of the largest follicle to LH cannot be ascribed solely to receptor-coupled adenylate cyclase activity. As shown by the forskolin experiment, the intrinsic activity of the adenylate cyclase-cAMP system is greatest in the small F5, F6 follicles which respond only minimally in terms of steroidogenesis to either a receptor dependent agonist (LH) or a nonreceptor agonist (forskolin).

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