scholarly journals Delayed effect of heat stress on steroid production in medium-sized and preovulatory bovine follicles

Reproduction ◽  
2001 ◽  
pp. 745-751 ◽  
Author(s):  
Z Roth ◽  
R Meidan ◽  
A Shaham-Albalancy ◽  
R Braw-Tal ◽  
D Wolfenson
Keyword(s):  
Heat Stress ◽  
Granulosa Cells ◽  
Follicular Fluid ◽  
Heat Exposure ◽  
Low Fertility ◽  
Delayed Effect ◽  
Steroid Production ◽  
Thecal Cells ◽  
Preovulatory Follicles ◽  
Subsequent Cycle

During the autumn, the conception rate of dairy cattle in warm countries is low although ambient temperatures have decreased and cows are no longer exposed to summer thermal stress, indicating that there may be a delayed effect of heat stress on cattle fertility. Two experiments were conducted to examine possible delayed effects of heat stress on follicular characteristics and steroid production at two distinct stages of follicular growth: medium-sized and preovulatory follicles, 20 and 26 days after heat exposure, respectively. Lactating cows were subjected to heat stress for 12 h a day in an environmental chamber, during days 2-6 of a synchronized oestrous cycle. In Expt 1, ovaries were collected on day 3 of the subsequent cycle, before selection of the dominant follicle, and medium-sized follicles were classified as atretic or healthy. In Expt 2, on day 7 of the subsequent cycle, PGF(2a) was administered and preovulatory follicles were collected 40 h later. In both experiments, follicular fluid was aspirated, granulosa and thecal cells were incubated, and steroid production was determined. In healthy medium-sized follicles (Expt 1), oestradiol production by granulosa cells and androstenedione production by thecal cells were lower (P < 0.05) and the concentration of progesterone in the follicular fluid was higher in cows that had been previously heat-stressed than in control cows (P < 0.05). In preovulatory follicles (Expt 2), the viability of granulosa cells was lower (P < 0.05) and the concentration of androstenedione in the follicular fluid and its production by thecal cells were lower (P < 0.05) in cows that had been previously heat-stressed than in control cows. In both experiments, the oestradiol concentrations in the follicular fluids were not altered by heat stress. These results demonstrate a delayed effect of heat stress on steroid production and follicular characteristics in both medium-sized and preovulatory follicles; this effect could be related to the low fertility of cattle in the autumn.

Immediate and delayed effects of heat stress on follicular development and its association with plasma FSH and inhibin concentration in cows

Reproduction ◽  
2000 ◽  
pp. 83-90 ◽  
Author(s):  
Z Roth ◽  
R Meidan ◽  
R Braw-Tal ◽  
D Wolfenson
Keyword(s):  
Heat Stress ◽  
Follicular Development ◽  
Oestrous Cycle ◽  
Low Fertility ◽  
Delayed Effect ◽  
Delayed Effects ◽  
Treatment Groups ◽  
Follicular Wave ◽  
Subsequent Cycle ◽  
Follicular Dynamics

The aim of this study was to characterize the immediate effects of heat stress on plasma FSH and inhibin concentrations, and its involvement in follicular dynamics during a complete oestrous cycle, and to examine a possible delayed effect of heat stress on follicular development. Holstein dairy cows were oestrous synchronized and randomly assigned to either cooled (n = 7) or heat-stressed (n = 6) treatment groups. During a complete oestrous cycle, control cows, which were cooled, maintained normothermia, whereas heat-stressed cows, which were exposed to direct solar radiation, developed hyperthermia. At the end of this oestrous cycle (treated cycle), both groups were cooled and maintained normothermia for the first 10 days of the subsequent oestrous cycle. Throughout this period, follicular development was examined by ultrasonography, and plasma samples were collected. During the second follicular wave of the treated oestrous cycle, a significantly larger cohort of medium sized follicles (6-9 mm) was found in heat-stressed cows than in cooled cows (P < 0.05). The enhanced growth of follicles in this wave in heat-stressed cows was associated with a higher plasma FSH increase which lasted 4 more days (days 8-13 of the oestrous cycle; P < 0.05), and coincided with a decrease in the plasma concentration of immunoreactive inhibin (days 5-18 of the oestrous cycle; P < 0.05). During the follicular phase (days 17-20 of the treated cycle), heat-stressed cows showed an increase in the number of large follicles (>/= 10 mm), and the preovulatory plasma FSH surge was significantly higher in heat-stressed cows than in cooled cows (P < 0.01). The effect of heat stress was also observed during the first follicular wave of the subsequent cycle: the postovulatory plasma FSH concentration was higher (P < 0.01), but fewer medium follicles developed, and the first follicular wave decreased at a slower rate in previously heat-stressed cows than in cooled cows (0.40 and 0.71 follicles per day, respectively). This study shows both immediate and delayed effects of heat stress on follicular dynamics, which were associated with high FSH and low inhibin concentrations in plasma. These alterations may have physiological significance that could be associated with low fertility of cattle during the summer and autumn.

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.

scholarly journals 2,3,7,8-Tetrachlorodibenzo-p-dioxin alters steroid secretion but does not affect cell viability and the incidence of apoptosis in porcine luteinised granulosa cells

2014 ◽  
Vol 62 (3) ◽  
pp. 408-421 ◽  
Author(s):  
Olga Jablonska ◽  
Joanna Piasecka-Srader ◽  
Anna Nynca ◽  
Agnieszka Kołomycka ◽  
Anna Robak ◽  
...  
Keyword(s):  
Cell Viability ◽  
Granulosa Cells ◽  
Steroid Hormone ◽  
Annexin V ◽  
Steroid Production ◽  
Steroid Secretion ◽  
Porcine Granulosa Cells ◽  
Affect Cell Viability ◽  
Preovulatory Follicles ◽  
Induced Apoptosis

The compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a by-product of human industrial activity, was found to affect ovarian steroidogenesis in animals, but the mechanism of its action is still unclear. The aims of the study were to examine the effect of TCDD on (1) progesterone (P4) and oestradiol (E2) production by granulosa cells isolated from medium (3–6 mm) and preovulatory (≥ 8 mm) porcine follicles, (2) the viability of the cells, and (3) the incidence of apoptosis. Porcine granulosa cells were cultured (48 h) with or without TCDD (100 pM, 100 nM). Steroid hormone concentrations in the medium were determined by radioimmunoassay. The viability of granulosa cells was tested spectrophotometrically (alamarBlue™ assay). Apoptosis was evaluated by flow cytometry using Annexin V and by TUNEL assay. The higher dose of TCDD (100 nM) significantly inhibited P4 and stimulated E2 production by luteinised granulosa cells isolated from medium follicles. The lower dose of TCDD (100 pM) significantly stimulated P4 and inhibited E2 secretion by the cells isolated from preovulatory follicles. None of the two TCDD doses affected cell viability or induced apoptosis in granulosa cells. In conclusion, TCDD directly affected steroid production by granulosa cells obtained from mature pigs, but the effect of TCDD was not due to its cytotoxicity.

Oocyte-secreted factros regulate granulosa cell steroidogenesis

Zygote ◽  
1996 ◽  
Vol 4 (04) ◽  
pp. 317-321 ◽  
Author(s):  
Barbara C. Vanderhyden
Keyword(s):  
Cell Proliferation ◽  
Germ Cell ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Inhibitory Factor ◽  
Preovulatory Follicles ◽  
Loss Of Contact

Investigations of strains of mice defective in germ cell development have revealed the importance of oocytes for the initial stages of folliculogenesis (Pellaset al., 1991; Huanget al., 1993). Various aspects of follicular development are dependent upon and/or influenced by the presence of oocytes, including granulosa cell proliferation (Vanderhydenet al., 1990, 1992) and cumulus expansion (Buccioneet al., 1990; Salustriet al., 1990; Vanderhydenet al., 1990; Vanderhyden, 1993). We are investigating the possibility that oocytes influence one of the primary functions of granulosa cells: steroidogenesis. In many species, granulosa cells removed from preovulatory follicles luteinisein vitro(Channinget al., 1982), presumably due to loss of contact with follicular luteinisation inhibitory factor(s). Indeed, follicular fluid can prevent granulosa cell luteinisationin vitro(Ledwitz-Rigbyet al., 1977). Follicular fluid, however, may simply be the medium for transport of factors secreted by oocytes to regulate granulosa cell activities.

scholarly journals The Cultivation of Human Granulosa Cells

2008 ◽  
Vol 51 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Lenka Brůčková ◽  
Tomáš Soukup ◽  
Jiří Moos ◽  
Martina Moosová ◽  
Jana Pavelková ◽  
...  
Keyword(s):  
Growth Factors ◽  
Granulosa Cells ◽  
Follicular Fluid ◽  
Doubling Time ◽  
Ovarian Follicle ◽  
Vitro Fertilization ◽  
Thecal Cells ◽  
Cell Doubling Time

The major functions of granulosa cells (GCs) include the production of steroids, as well as a myriad of growth factors to interact with the oocyte during its development within the ovarian follicle. Also FSH stimulates GCs to convert androgens (coming from the thecal cells) to estradiol by aromatase. However, after ovulation the GCs produce progesterone that may maintain a potential pregnancy. Experiments with human GCs are mainly focused on the purification of GCs from ovarian follicular fluid followed by FACS analysis or short-term cultivation. The aim of our study was to cultivate GCs for a long period, to characterize their morphology and phenotype. Moreover, we have cultivated GCs under gonadotropin stimulation in order to simulate different pathological mechanisms during folliculogenesis (e.g. ovarian hyperstimulation syndrome). GCs were harvested from women undergoing in vitro fertilization. Complex oocyte-cumulus oophorus was dissociated by hyaluronidase. The best condition for transport of GCs was optimized as short transport in follicular fluid at 37 °C. GCs expansion medium consisted of DMEM/F12, 2 % FCS, ascorbic acid, dexamethasone, L-glutamine, gentamycine, penicillin, streptomycin and growth factors (EGF, bFGF). GCs transported in follicular fluid and cultivated in 2 % FCS containing DMEM/F12 medium supplemented with follicular fluid presented increased adhesion, proliferation, viability and decreased doubling time. Cell viability was 92 % and mean cell doubling time was 52 hrs. We have optimized transport and cultivation protocols for long-term cultivation of GCs.

Modulating effect of growth hormone on the functional state of cultured cells from hen preovulatory follicles

2022 ◽  
pp. 108-113
Author(s):  
A. Smekalova ◽  
O. Mityashova ◽  
O. Aleinikova ◽  
E. Montvila ◽  
I. Lebedeva
Keyword(s):  
Granulosa Cells ◽  
Final Stage ◽  
Proliferative Activity ◽  
Laying Hens ◽  
Theca Cells ◽  
Apoptotic Protein ◽  
Thecal Cells ◽  
Preovulatory Follicles ◽  
Regulation Of Growth

Somatotropic hormone (STH) is an important positive modulator of ovarian function in mammals. Local production of STH and the expression of the corresponding specific receptors were also detected in hen ovarian follicles, which indicates the participation of this hormone in the endocrine/paracrine control of folliculogenesis in birds. Nevertheless, the role of STH in the regulation of growth of avian follicles at the final stage of maturation is still not clear.Objective: To study in vitro the effect of STH on the proliferative activity and apoptotic changes of granulosa and theca cells from preovulatory follicles of domestic hens.Materials and methods. Young laying hens aged 34-35 weeks with a long clutch were used in the experiments. Granulosa and theca cells were isolated from the largest yellow follicle in the hierarchy (F1). The cells were cultured in a medium containing 10% fetal bovine serum until a monolayer was formed, and then for 24 h in the medium without serum in the absence (control) or in the presence of STH at various concentrations (1-100 ng/ml). The proliferative activity and apoptotic changes in the cells were assessed by immunocytochemical assay, based on the expression level of proliferating cell nuclear antigen PCNA and pro-apoptotic protein Bax, respectively.Results. The proportion of PCNA-positive granulosa cells increased 1.3-1.8 times (P<0.01-0.05) as compared to control with increasing the content of STH in the medium to 10-100 ng/ml. Furthermore, within this concentration range, the studied hormone reduced 1.2-1.6 times (P<0.05) the relative number of granulosa cells with the positive reaction to Bax. The sensitivity of theca cells to the growth-stimulating effect of STH was lower than that of granulosa cells. Such the effect of STH led to an increase in the proportion of PCNA-positive thecal cells by 1.2-1.3 times (P<0.05) and was detected only at concentrations of 25 and 100 ng/ml. Meanwhile, STH (25-100 ng/ml) increased 1.3 times (P<0.05) the level of Bax expression in theca cells.Conclusions. The results of the present study indicate the stimulating effect of STH in vitro on the proliferative activity of granulosa and theca cells from the most mature hen preovulatory follicle. In addition, STH is able to reduce the expression of the pro-apoptotic protein Bax in granulosa cells and increase this expression in thecal cells. Thus, the data obtained indicate the possible participation of STH in the regulation of growth and development of follicles at the final stage of maturation during the period of maximum egg-laying intensity in laying hens.

INHIBITORY ACTION OF FOLLICULAR FLUID ON PROGESTERONE AND PROSTAGLANDIN SYNTHESIS IN BOVINE FOLLICLES

1979 ◽  
Vol 82 (1) ◽  
pp. 27-31 ◽  
Author(s):  
MORDECHAI SHEMESH
Keyword(s):  
Granulosa Cells ◽  
Follicular Fluid ◽  
Culture Medium ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Male Rat ◽  
Prostaglandin Synthetase ◽  
Preovulatory Follicles ◽  
Prostaglandin F ◽  
Twofold Decrease

SUMMARY The present studies examined the inhibitory effect of mid-cycle and preovulatory bovine follicular fluid (bFF) on the secretion of progesterone and prostaglandin F2α (PGF2α) by bovine theca and granulosa cells cultured in tissue culture Medium 199. The inhibitory effect of bFF on the secretion of PGF2α by incubated and cultured hemipituitary glands of male rats was also studied. Addition of 5, 10 or 20% charcoal-extracted, mid-cycle bFF to the culture medium caused a twofold decrease in the accumulation of both progesterone and PGF2α by the cultured granulosa cells (P < 0·01). In contrast, when preovulatory bFF was used, there was no inhibitory effect on secretion of progesterone and PGF2α. The addition of 10% mid-cycle bFF to the culture medium caused a two- to fourfold decrease in the accumulation of both PGF2α and progesterone by the cultured theca (P < 0·008). However, in the presence of 1 μg LH/ml, the inhibitory effect of mid-cycle bFF on progesterone and PGF2α secretion was abolished. The secretion of PGF2α was significantly (P < 0·03) decreased in male rat hemipituitary glands after 5 h of incubation or 18 h of culture. These findings suggest that bFF from mid-cycle follicles inhibits prostaglandin synthetase as well as luteinization. The inhibition disappeared with bFF from preovulatory follicles.

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