scholarly journals Effects of leptin administration and feed restriction on thecal leucocytes in the preovulatory rat ovary and the effects of leptin on meiotic maturation, granulosa cell proliferation, steroid hormone and PGE2 release in cultured rat ovarian follicles

Reproduction ◽  
2002 ◽  
pp. 891-898 ◽  
Author(s):  
PS Duggal ◽  
NK Ryan ◽  
KH Van der Hoek ◽  
LJ Ritter ◽  
DT Armstrong ◽  
...  

Leptin is expressed by adipocytes and is thought to play a role in regulating food intake and in reproduction. It has been demonstrated that acute leptin administration to immature gonadotrophin-primed rats in vivo inhibits ovulation and causes a decline in food intake. However, feed restriction alone does not inhibit ovulation. Two experiments were designed to investigate the mechanism of leptin-induced inhibition of ovulation. In the first experiment, which was prompted by the importance of ovarian leucocytes in ovulation, the role of leucocytes in leptin-induced inhibition of ovulation was investigated. The second experiment investigated whether high leptin concentrations could inhibit other factors important to ovulation, such as meiotic competence of oocytes, granulosa cell proliferation, steroid or PGE(2) release, and interleukin 1beta production, in vitro. In the first experiment, the populations of neutrophils and monocytes-macrophages in the preovulatory follicles of gonadotrophin-primed, leptin-treated and -untreated rats were examined. A decrease in food intake, as a result of either leptin treatment or feed restriction, specifically reduced the numbers of neutrophils and monocytes-macrophages infiltrating the theca interna of preovulatory follicles without affecting the numbers found in the stroma. The findings show that reduced infiltration of thecal neutrophils and macrophages into preovulatory follicles is a response to reduced food intake. Furthermore, this reduction is not the direct cause of the leptin-induced inhibition of ovulation. In the second experiment, ovarian follicles were cultured for 4 or 12 h in the presence or absence of the following hormones: FSH (500 miu), insulin-like growth factor I (IGF-I) (50 ng ml(-1)), LH (100 ng ml(-1)) and leptin (300 ng ml(-1)). The results demonstrated that high concentrations of leptin in follicle culture do not affect meiotic maturation or steroid release, but tend to inhibit release of PGE 2 (although this result was not significant). DNA synthesis in granulosa cells was not inhibited by leptin in FSH- and IGF-I-supplemented culture media. These results are in agreement with previous studies that have shown that leptin inhibits the stimulatory effects of IGF-I on FSH-stimulated oestradiol production in rat granulosa cells without affecting progesterone production. In summary, leptin does not appear to have an adverse effect on the components of ovulation tested in this study, and therefore must impact on the ovulatory cascade in a way that remains to be defined.

1994 ◽  
Vol 140 (2) ◽  
pp. 313-319 ◽  
Author(s):  
P Ovesen ◽  
H J Ingerslev ◽  
H Ørskov ◽  
T Ledet

Abstract Numerous clinical and experimental observations have suggested that GH is important in ovarian function. We have investigated the effect of GH alone and GH in combination with FSH on the secretion of oestradiol, progesterone, insulin-like growth factor-I (IGF-I) and IGF-binding protein-1 (IGFBP-1) and on [3H]thymidine incorporation in cultured human luteinized granulosa cells. Granulosa cells from patients undergoing treatment for in vitro fertilization were isolated and cultured for 2 days in culture medium with 10% serum. After this preincubation, the medium was removed and the cells were incubated with GH (1, 10 and 100 μg/l) with or without FSH in serum-free medium and in the presence of [3H]methylthymidine (2 μCi/ml). GH alone resulted in a significant dose-dependent increase of oestradiol (P<0·05) and in IGFBP-1 (P<0·002) in the medium. The release of IGF-I was undetectable and there was no increase in [3H]thymidine incorporation with GH alone. Neither GH nor FSH alone stimulated granulosa cell proliferation or progesterone release, while the combination induced increases (P<0·001) in both. The stimulatory effect of GH on steroidogenesis, IGFBP-1 production and granulosa cell proliferation supports a putative role for GH in the regulation of ovarian function. Journal of Endocrinology (1994) 140, 313–319


Zygote ◽  
1996 ◽  
Vol 4 (04) ◽  
pp. 317-321 ◽  
Author(s):  
Barbara C. Vanderhyden

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.


Development ◽  
2000 ◽  
Vol 127 (19) ◽  
pp. 4277-4291 ◽  
Author(s):  
S. Dupont ◽  
A. Krust ◽  
A. Gansmuller ◽  
A. Dierich ◽  
P. Chambon ◽  
...  

The functions of estrogen receptors (ERs) in mouse ovary and genital tracts were investigated by generating null mutants for ERalpha (ERalphaKO), ERbeta (ERbetaKO) and both ERs (ERalphabetaKO). All ERalphaKO females are sterile, whereas ERbetaKO females are either infertile or exhibit variable degrees of subfertility. Mast cells present in adult ERalphaKO and ERalphabetaKO ovaries could participate in the generation of hemorrhagic cysts. Folliculogenesis proceeds normally up to the large antral stage in both ERalphaKO and ERbetaKO adults, whereas large antral follicles of ERalpha+/−ERbetaKO and ERalphabetaKO adults are markedly deficient in granulosa cells. Similarly, prematurely developed follicles found in prepubertal ERalphaKO ovaries appear normal, but their ERalphabetaKO counterparts display only few granulosa cell layers. Upon superovulation treatment, all prepubertal ERalphaKO females form numerous preovulatory follicles of which the vast majority do not ovulate. The same treatment fails to elicit the formation of preovulatory follicles in half of the ERbetaKO mice and in all ERalpha+/−/ERbetaKO mice. These and other results reveal a functional redundancy between ERalpha and ERbeta for ovarian folliculogenesis, and strongly suggest that (1) ERbeta plays an important role in mediating the stimulatory effects of estrogens on granulosa cell proliferation, (2) ERalpha is not required for follicle growth under wild type conditions, while it is indispensable for ovulation, and (3) ERalpha is also necessary for interstitial glandular cell development. Our data also indicate that ERbeta exerts some function in ERalphaKO uterus and vagina. ERalphabetaKO granulosa cells localized within degenerating follicles transform into cells displaying junctions that are unique to testicular Sertoli cells. From the distribution pattern of anti-Mullerian hormone (AMH) in ERalphabetaKO ovaries, it is unlikely that an elevated AMH level is the cause of Sertoli cell differentiation. Our results also show that cell proliferation in the prostate and urinary bladder of old ERbetaKO and ERalphabetaKO males is apparently normal.


Reproduction ◽  
2000 ◽  
pp. 433-442 ◽  
Author(s):  
OM Onagbesan ◽  
J Mast ◽  
B Goddeeris ◽  
E Decuypere

This study demonstrates the effects of recombinant human tumour necrosis factor a (rhTNF-alpha) and conditioned medium of the HD11-transformed chicken macrophage cell line on cultured chicken granulosa cells. Effects were studied on basal, IGF-I- and LH-stimulated progesterone production and cell proliferation. Recombinant human TNF-alpha stimulated basal progesterone production in a dose-dependent manner in the granulosa cells of the largest follicle but had no effect on cells from the third largest follicle. TNF-alpha stimulated and sometimes inhibited progesterone production stimulated by IGF-I and LH alone or in combination depending on the size of the follicle and the concentration of LH or IGF-I applied. However, the inhibitory effect of TNF-alpha was significantly more pronounced in cells from the third largest follicle when high concentrations of IGF-I, LH or a combination of both were applied. TNF-alpha had no effect on basal cell proliferation in both the largest and the third largest follicles, but regulated responses to IGF-I and a combination IGF-I and LH in the cells of the third largest follicle but not those of the largest follicle. The data indicate that the normal hierarchy of follicles is maintained in the chicken ovary through the regulation of the activity of IGF-I and its interaction with LH. Conditioned medium of LPS-activated HD11 macrophages mimicked the effects of TNF-alpha and its interaction with IGF-I and LH on progesterone production and cell proliferation. The observation that the HD11-conditioned medium contained TNF-alpha indicates that TNF-alpha produced by macrophages found in chicken follicles modulates granulosa cell growth and differentiation.


2006 ◽  
Vol 189 (2) ◽  
pp. 329-339 ◽  
Author(s):  
L J Spicer ◽  
P Y Aad ◽  
D Allen ◽  
S Mazerbourg ◽  
A J Hsueh

In addition to gonadotropins, steroidogenesis and proliferation of granulosa cells during follicular development are controlled by a number of intraovarian factors including growth differentiation factor-9 (GDF-9), bone morphogenetic protein-4 (BMP-4), and IGF-I. The objective of this study was to determine the effect of GDF-9 and BMP-4 and their interaction with IGF-I and FSH on ovarian granulosa cell function in cattle. Granulosa cells from small (1–5 mm) and large (8–22 mm) follicles were collected from bovine ovaries and cultured for 48 h in medium containing 10% fetal calf serum and then treated with various hormones in serum-free medium for an additional 48 h. We evaluated the effects of GDF-9 (150–600 ng/ml) and BMP-4 (30 ng/ml) during a 2-day exposure on hormone-induced steroidogenesis and cell proliferation. In FSH plus IGF-I-treated granulosa cells obtained from small follicles, 300 ng/ml GDF-9 reduced (P<0.05) progesterone production by 15% and 600 ng/ml GDF-9 completely blocked (P<0.01) the IGF-I-induced increase in progesterone production. In comparison, 300 and 600 ng/ml GDF-9 decreased (P<0.05) estradiol production by 27% and 71% respectively, whereas 150 ng/ml GDF-9 was without effect (P>0.10). Treatment with 600 ng/ml GDF-9 increased (P<0.05) numbers (by 28%) of granulosa cells from small follicles. In the same cells treated with FSH but not IGF-I, co-treatment with 600 ng/ml GDF-9 decreased (P<0.05) progesterone production (by 28%), increased (P<0.05) cell numbers (by 60%), and had no effect (P>0.10) on estradiol production. In FSH plus IGF-I-treated granulosa cells obtained from large follicles, GDF-9 caused a dose-dependent decrease (P<0.05) in IGF-I-induced progesterone (by 13–48%) and estradiol (by 20–51%) production. In contrast, GDF-9 increased basal and IGF-I-induced granulosa cell numbers by over 2-fold. Furthermore, treatment with BMP-4 also inhibited (P<0.05) steroidogenesis by 27–42% but had no effect on cell numbers. To elucidate downstream signaling pathways, granulosa cells from small follicles were transfected with similar to mothers against decapentaplegics (Smad) binding element (CAGA)- or BMP response element (BRE)-promoter reporter constructs. Treatment with GDF-9 (but not BMP-4) activated the Smad3-induced CAGA promoter activity, whereas BMP-4 (but not GDF-9) activated the Smad1/5/8-induced BRE promoter activity. We have concluded that bovine granulosa cells are targets of both GDF-9 and BMP-4, and that oocyte-derived GDF-9 may simultaneously promote granulosa cell proliferation and prevent premature differentiation of the granulosa cells during growth of follicles, whereas theca-derived BMP-4 may also prevent premature follicular differentiation.


1997 ◽  
Vol 153 (2) ◽  
pp. 231-240 ◽  
Author(s):  
C G Gutiérrez ◽  
B K Campbell ◽  
D G Armstrong ◽  
R Webb

Abstract Insulin-like growth factor-binding protein (IGFBP) extraction protocols were tested for their efficacy in removing IGFBPs from bovine plasma and bovine granulosa cell culture medium compared with standard acid exclusion chromatography. Traditional extraction methods, acidification, Sep–Pak, ethanol:acetone:acetic acid (EAA) and EAA-cryoprecipitation (EAA-C), failed to remove all the IGFBPs from both granulosa cell culture medium and plasma. However, EAA and EAA-C treatment of plasma samples did give values similar to those obtained by acid exclusion HPLC, when corrected for extraction efficiency. There was an inverse relationship between insulin-like growth factor-I (IGF-I) concentration in plasma samples, as measured using HPLC chromatography, and IGF-I concentration after EAA extraction. Furthermore, the interference caused by residual IGFBPs differed between samples taken from animals given various treatments that altered peripheral IGF-I concentrations. As for plasma samples, EAA was the most effective extraction method for culture media, but residual IGFBPs caused an overestimation of IGF-I concentrations. In culture media, but not plasma, it was possible to block the interference of IGFBPs in the IGF-I assay, in both extracted and non-extracted culture samples, by the addition of excess IGF-II. Using this assay procedure, no IGF-I production by bovine granulosa cells was detected. This was confirmed by HPLC acid chromatography. It is concluded that HPLC extraction is needed for the accurate measurement of peripheral IGF-I concentrations. For granulosa cell culture media it is possible to measure IGF-I concentrations in non-extracted samples if the IGFBPs are blocked by adding IGF-II. Using either this assay, or after HPLC acid chromatography, no IGF-I was detected in culture media, suggesting that IGF-I is not produced by non-luteinised bovine granulosa cells. Journal of Endocrinology (1997) 153, 231–240


1994 ◽  
Vol 142 (3) ◽  
pp. 497-510 ◽  
Author(s):  
D Monniaux ◽  
C Pisselet ◽  
J Fontaine

Abstract Granulosa cells of ovarian follicles both proliferate and undergo differentiation. In vivo, an inverse relationship between proliferation and steroidogenesis is observed. However, both processes can be enhanced by insulin-like growth factor-I (IGF-I) in vitro. Studies were undertaken in the ewe to understand the mechanisms controlling the balance between proliferation and differentiation in cultured granulosa cells from antral follicles better. For this purpose, granulosa cells from ovine small follicles (1–3 mm in diameter) and large follicles (5–7 mm in diameter) were compared for progesterone secretion, cytochrome P450 side-chain cleavage (P450scc) expression and their proportions of non-proliferating (G0) cells, in response to IGF-I and FSH stimulation in vitro. IGF-I mainly enhanced the proliferation of granulosa cells from small follicles but it strongly increased progesterone secretion and P450scc expression in granulosa cells from large follicles, in synergy with FSH. Blocking granulosa cell proliferation by the administration of colcemid or aphidicolin had no effect or a weak stimulating effect on progesterone secretion. At the beginning of the culture period, the proportion of non-proliferating cells, estimated by continuous [3H]thymidine labelling experiments, was clearly higher in large than in small follicles (91% vs 30%, P<0·001). For both cell types, treatment with IGF-I in vitro reduced the proportion of non-proliferating cells at 72 h of culture (40% vs 70% respectively in IGF-I-stimulated and unstimulated cells from large follicles, P<0·001, and 17% vs 30% respectively in IGF-I-stimulated and unstimulated cells from small follicles, P<0·001). Treatment with FSH had no effect on the proportion of non-proliferating cells. As revealed by immunohistochemistry experiments, IGF-I, in synergy with FSH, clearly increased the percentage of cells expressing P450scc enzyme and the intensity of staining in granulosa cells from large follicles. Unexpectedly, heavily stained cells in mitosis were observed in IGF-I-stimulated cells from large follicles after 96 h of culture, suggesting that dividing cells might also produce progesterone. Overall, these results support the hypothesis that the growth-promoting and the cytodifferentiative effects of IGF-I are clearly distinct. Moreover, they suggest that uncoupling between proliferation and steroidogenesis may occur in cultured ovine granulosa cells. The loss of proliferative activity accompanying terminal follicular growth in vivo could be reversed in vitro. During terminal follicular growth in vivo, the existence of an active mechanism inhibiting granulosa cell proliferation, and unrelated to terminal differentiation, is therefore strongly suspected. Journal of Endocrinology (1994) 142, 497–510


Endocrinology ◽  
2009 ◽  
Vol 150 (2) ◽  
pp. 929-935 ◽  
Author(s):  
Pradeep P. Kayampilly ◽  
K. M. J. Menon

FSH, acting through multiple signaling pathways, regulates the proliferation and growth of granulosa cells, which are critical for ovulation. The present study investigated whether AMP-activated protein kinase (AMPK), which controls the energy balance of the cell, plays a role in FSH-mediated increase in granulosa cell proliferation. Cells isolated from immature rat ovaries were grown in serum-free, phenol red free DMEM-F12 and were treated with FSH (50 ng/ml) for 0, 5, and 15 min. Western blot analysis showed a significant reduction in AMPK activation as observed by a reduction of phosphorylation at thr 172 in response to FSH treatment at all time points tested. FSH also reduced AMPK phosphorylation in a dose-dependent manner with maximum inhibition at 100 ng/ml. The chemical activator of AMPK (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, 0.5 mm) increased the cell cycle inhibitor p27 kip expression significantly, whereas the AMPK inhibitor (compound C, 20 μm) and FSH reduced p27kip expression significantly compared with control. FSH treatment resulted in an increase in the phosphorylation of AMPK at ser 485/491 and a reduction in thr 172 phosphorylation. Inhibition of Akt phosphorylation using Akt inhibitor VIII reversed the inhibitory effect of FSH on thr 172 phosphorylation of AMPK, whereas ERK inhibitor U0126 had no effect. These results show that FSH, through an Akt-dependent pathway, phosphorylates AMPK at ser 481/495 and inhibits its activation by reducing thr 172 phosphorylation. AMPK activation by 5-amino-imidazole-4-carboxamide-1-β-d-ribofuranoside treatment resulted in a reduction of cell cycle regulatory protein cyclin D2 mRNA expression, whereas FSH increased the expression by 2-fold. These results suggest that FSH promotes granulosa cell proliferation by increasing cyclin D2 mRNA expression and by reducing p27 kip expression by inhibiting AMPK activation through an Akt-dependent pathway. FSH stimulates granulosa cell proliferation by reducing cell cycle inhibitor p27 kip through AMP kinase inhibition.


Sign in / Sign up

Export Citation Format

Share Document