scholarly journals Differential effects of activin A on basal and gonadotrophin-induced secretion of inhibin A and progesterone by granulosa cells from preovulatory (F1-F3) chicken follicles

Reproduction ◽  
2002 ◽  
pp. 649-657 ◽  
Author(s):  
TM Lovell ◽  
RT Gladwell ◽  
NP Groome ◽  
PG Knight

Previous work has shown that activin A is expressed selectively within the theca rather than the granulosa layer of preovulatory chicken follicles. In the present study, this finding was verified and the potential paracrine actions of activin A on basal and gonadotrophin-induced secretion of inhibin A, inhibin B and progesterone by granulosa cells from the three largest preovulatory follicles (F1-F3) were investigated. Treatment with activin A (0, 0.25, 2.5 and 25 ng ml(-1)) alone increased inhibin A secretion markedly in a follicle- and time-dependent manner, with the greatest response (up to 15-fold increase; P < 0.0001) in F1 follicles after 3 days of treatment. In contrast, activin A alone had no effect on progesterone output at any time. Cells from F3 follicles were more responsive to FSH than were F1 cells in terms of both inhibin A (P < 0.02) and progesterone (P < 0.01) secretion. Furthermore, activin A greatly enhanced FSH-induced secretion of both inhibin A (up to tenfold; P < 0.0001) and progesterone (up to sixfold; P < 0.0001). In terms of LH-induced inhibin A and progesterone secretion, cells from F1, F2 and F3 follicles showed similar responses. Co-treatment with activin A enhanced LH-induced secretion of inhibin A markedly (up to ninefold; P < 0.0001) but had only a marginal effect on LH-induced progesterone secretion (up to twofold; P < 0.001). The presence of activin receptor subtypes IA, IB, IIA and IIB in cultured granulosa cells from F1, F2 and F3 follicles was demonstrated using immunocytochemistry. These findings support the hypothesis that activin A secreted by the theca layers of avian preovulatory follicles exerts a local paracrine action on granulosa cells to modulate 'basal' inhibin A secretion and to upregulate gonadotrophin-induced secretion of both inhibin A and progesterone. However, the extent to which this local role of activin A contributes to the generation of the preovulatory LH-progesterone surge remains to be established.

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2027
Author(s):  
Na Sun ◽  
Yutong Zhang ◽  
Yaxin Hou ◽  
Yanyan Yi ◽  
Jianhua Guo ◽  
...  

Osthole (Ost) is an active constituent of Cnidium monnieri (L.) Cusson which possesses anti-inflammatory and anti-oxidative properties. It also has estrogen-like activity and can stimulate corticosterone secretion. The present study was aimed to check the role of Ost on progesterone (P4) secretion in cultured granulosa cells obtained from hen preovulatory follicles. Different concentrations (5, 2.5, and 1.25 µg/mL) of Ost was added to granulosa cells for 6, 12, 18, and 24 h to investigate the level of progesterone secretions using enzyme linked immunosorbent assay (ELISA). The results showed that progesterone secretion was significantly increased in cells treated with Ost at 2.5 μg/mL. Also, qRT-PCR showed that mRNA expression of steroidogenic acute regulatory protein (StAR) was significantly up-regulated by Ost at 2.5 μg/mL concentration. Cytochrome P450 side-chain cleavage (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD) was significantly up-regulated by Ost. However, no significant differences were observed for the expression of proliferating cell nuclear antigen (PCNA). The protein expression of StAR, P450scc and 3β-HSD were significantly up-regulated by Ost treatment. The concentration of cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) in cell lysates showed no change with Ost treatment at 2.5 μg/mL by ELISA. An ROS kit showed non-significant difference in the level of reactive oxygen species (ROS). In conclusion, Ost treatment at a concentration of 2.5 μg/mL for 24 h had significantly up-regulated P4 secretion by elevating P450scc, 3β-HSD and StAR at both gene and protein level in granulosa cells obtained from hen preovulatory follicles.


Reproduction ◽  
2007 ◽  
Vol 134 (2) ◽  
pp. 293-306 ◽  
Author(s):  
Sara L Al-Musawi ◽  
Richard T Gladwell ◽  
Philip G Knight

The aims were to examine ovarian expression of bone morphogenetic protein (BMP) ligands/receptor mRNAs in the chicken and to test the hypothesis that theca-derived BMP(s) modulates granulosa cell function in a paracrine manner. RT-PCR revealed expression of multiple BMPs in granulosa and theca cells from prehierarchical and preovulatory follicles with greater expression in theca cells; both cell types expressed BMP receptors-IA, -IB and -II consistent with tissue responsiveness. Preovulatory granulosa cells (F1, F2 and F3/4) were cultured with BMP-6 (expressed by theca but not granulosa) in the presence/absence of LH, FSH or 8-Br-cAMP. BMP-6 increased ‘basal’ and gonadotrophin-induced inhibin-A and progesterone secretion by each cell type but did not enhance the effect of 8-Br-cAMP. This indicates that the observed synergism between BMP-6 and gonadotrophin might involve BMP-induced up-regulation of gonadotrophin receptors. In support of this, BMP-6 alone increased LH-receptor (LHR) mRNA in F1 cells and FSH-receptor (FSHR) mRNA in F1, F2 and F3/4 cells. BMP-6 also enhanced LH/FSH-induced LHR transcript amount in each cell type but did not raise FSHR transcript amounts above those induced by BMP-6 alone. To further explore BMP-6 action on inhibin-A secretion, we quantified inhibin/activin subunits (α, βA, βB) mRNAs. Consistent with its effect on inhibin-A secretion, BMP-6 enhanced ‘basal’ expression of α- and βA-subunit mRNA in F1, F2 and F3/4 cells, and βB-subunit mRNA in F3/4 cells. BMP-6 markedly enhanced FSH/LH-induced expression of α-subunit in all follicles and FSH-induced βA-subunit in F2 and F3/4 follicles but not in F1 follicles. Neither BMP-6 alone, nor FSH/LH alone, affected ‘basal’ βB mRNA abundance. However, co-treatment with gonadotrophin and BMP-6 greatly increased βB-subunit expression, the response being lowest in F1 follicles and greatest in F3/4 follicles. Collectively, these results support the hypothesis that intraovarian BMPs of thecal origin have a paracrine role in modulating granulosa cell function in the chicken in a preovulatory stage-dependent manner.


1985 ◽  
Vol 110 (3) ◽  
pp. 401-407 ◽  
Author(s):  
T. Hillensjö ◽  
A. Sjögren ◽  
B. Strander ◽  
L. Nilsson ◽  
M. Wikland ◽  
...  

Abstract. Granulosa cells were obtained from human preovulatory follicles in 31 women undergoing in vitro fertilization and embryo transfer due to tubal infertility. Follicular maturation was stimulated and synchronized by treatment with Clomiphene or human menopausal gonadotrophin (hMG), or both, plus human chorionic gonadotrophin (hCG). Follicles were aspirated by ultrasound guided puncture approximately 34–36 h after the hCG injection. The granulosa cells were washed and suspended in modified medium 199 containing 10% foetal bovine serum and cultured as monolayers for 6–8 days in the absence and presence of hormones and reactants. Progesterone formation was analyzed by RIA. In general, the cells underwent morphological luteinization and secreted high amount of progesterone. Under basal conditions the secretion of progesterone was highest during the first 2 days in culture and then gradually declined. Progesterone secretion was stimulated by human LH, hCG and the adenylate cyclase stimulator forskolin, with a maximal effect between days 2–6. The β-adrenergic agonist isoproteronol in preliminary experiments potentiated the stimulatory effect of hCG but had no own stimulatory effect. No clear differences in progesterone secretion or responsiveness to in vitro stimulation relating to the various in vivo stimulation protocols were found.


Reproduction ◽  
2012 ◽  
Vol 143 (5) ◽  
pp. 637-650 ◽  
Author(s):  
J M Young ◽  
S Henderson ◽  
C Souza ◽  
H Ludlow ◽  
N Groome ◽  
...  

Little is known about the role of activin B during folliculogenesis. This study investigated the expression levels of activin/inhibin subunits (βA, βB, and α), steroid enzyme, and gonadotrophin receptors in theca (TC) and granulosa cells (GC) by QPCR and activin A and B and inhibin A protein levels in follicular fluid (FF) of developing sheep follicles during estrus and anestrus. The effect of activin B on androgen production from primary TC cultures in vitro was also assessed. During folliculogenesis, in anestrus and estrus, FF activin B concentrations and thecal and GC activin βB mRNA levels decreased as follicle diameter increased from 1–3 to >6 mm regardless of estrogenic status. Estrogenic preovulatory follicles had reduced concentrations of FF activins B and A, and TC and GCs expressed higher levels of activin βA mRNA at 3–4 mm, and TCs more inhibin α mRNA at >4 mm stages of development compared with nonestrogenic follicles. Activin B decreased androstenedione production from primary TCs in vitro, an effect blocked by inhibin A. Thus, sheep follicles 1–3 mm in diameter contained high FF levels of activin B, which decreased as the follicle size increased, and, like activin A, suppressed thecal androgen production in vitro, an effect blocked by inhibin. Furthermore, the theca of large estrogenic follicles expressed high levels of inhibin α and activin βA mRNA suggesting local thecal derived inhibin A production. This would inhibit the negative effects of thecal activins B and A ensuring maximum androgen production for enhanced estradiol production by the preovulatory follicle(s).


2004 ◽  
Vol 183 (1) ◽  
pp. 51-60 ◽  
Author(s):  
E C Chin ◽  
D R E Abayasekara

The corpus luteum formed after luteinization of follicular cells secretes progesterone under the control of luteinizing hormone (LH). Binding of LH to its G-protein-coupled receptor leads to the activation of the adenylate cyclase/ cyclic AMP (cAMP)/cAMP-dependent protein kinase (PKA) signalling pathway. The identification of a new class of cAMP-binding proteins termed ‘guanine nucleotide exchange factors’ (cAMP-GEFs) provides a means by which changes in cAMP could yield actions that are independent of PKA. Hence, in this study, we have explored the hypothesis that steroidogenesis in luteinizing cells is mediated in both a cAMP/PKA-dependent and cAMP-dependent, but PKA-independent, manner. Human granulosa cells were isolated from follicular aspirates of women undergoing assisted conception. Luteinizing human granulosa cells were cultured for up to 3 days in the presence of human (h)LH and the adenylate cyclase activator forskolin in the added presence or absence of increasing doses of the PKA inhibitors H89 (N-[2-(4-bromocinnamylamino)ethyl] 5-isoquinoline) and PKI (myristoylated protein kinase A inhibitor amide 14–22) or the cAMP antagonist, Rp-cAMP. Agonist-stimulated progesterone secretion was inhibited in a dose-dependent manner by the PKA inhibitors and the cAMP antagonist, with decreasing sensitivity as luteinization progressed. Pretreatment of granulosa cells for 4 h with human (h)LH reduced the effectiveness of H89 in inhibiting progester-one secretion. Under basal conditions, cAMP-GEFI expression increased progressively throughout culture, and this could be further enhanced when cells were incubated with increasing doses of LH and forskolin. Furthermore, incubation of cells in the presence of increasing concentrations of the novel cAMP-GEF-specific cAMP analogue, 8 CPT-2 ME-cAMP (8-(4-chloro-phenylthio)-2′-0-methyladenosine-3′,5′-cyclic monophosphate), increased progesterone secretion in a dose-dependent manner. The results show that increases in cAMP generated by LH and forskolin, in addition to activating PKA, also induce increases in cAMP-GEFI protein expression in luteinizing human granulosa cells. In addition, activation of cAMP-GEFI results in increased progesterone secretion. Hence, increases in cAMP lead to the activation of PKA-dependent, as well as PKA-independent but cAMP-dependent (via cAMP-GEFI), signalling mechanisms. Since cAMP-GEFs have the capacity to activate the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3-K)/protein kinase B (PKB) signalling pathways, these may provide the potential mechanisms by which cAMP-dependent but PKA-independent progesterone synthesis is regulated.


1985 ◽  
Vol 110 (2) ◽  
pp. 251-256 ◽  
Author(s):  
J. Steven Alexander ◽  
Thomas M. Crisp

Abstract. The effects of preincubating rat granulosa cells with FSH, LH, and Prl on subsequent Prl mediated progesterone secretion were investigated. Granulosa cells were isolated from ovarian follicles 50 h after injection of 5 IU PMSG and were then plated on poly-l-lysine coated coverslips in serum supplemented medium. Cells were preincubated for 24 h in the absence of hormones (control) or with the addition of either 0.25, 2.5, 25 ng/ml rat FSH or rat LH, or 1 μg/ml rat Prl. Following the preincubation period, cells were maintained for an additional 6 or 8 days in the presence or absence of 1 μg/ml Prl. When cells were preincubated with FSH or LH, only the two higher concentrations (2.5 and 25 ng/ml) stimulated significantly more progesterone secretion than control cultures during the 24 h preincubation period. For each series of preincubations, cells cultured for 6 or 8 days in the presence of Prl secreted significantly more progesterone at each day of culture than cells cultured without Prl. Cells preincubated and cultured with Prl secreted only 3–7-fold more progesterone than cells preincubated in control medium and then cultured with Prl. Preincubation with FSH or LH promoted a 20–45-fold increase in Prl mediated progesterone secretion compared to control preincubation cultures that also subsequently were cultured with Prl. The magnitude of Prl mediated progesterone secretion observed through 6 days of culturing was dose dependent on the preincubation concentration of FSH or LH. The establishment of an in vitro model system in which gonadotrophins enhance the responsiveness of granulosa cells to Prl in serum supplemented medium provides the opportunity for study of the regulatory mechanisms involved with the induction and maintenance of such responsiveness.


2001 ◽  
Vol 169 (2) ◽  
pp. 333-345 ◽  
Author(s):  
BK Campbell ◽  
DT Baird

The aim of these studies was to examine the origin, control and local actions of inhibin A in monovular species, using the sheep as a model. Experiment 1 examined the pattern of mRNA expression for the inhibin subunits in relation to follicular size and pattern of expression to other differentiative markers in granulosa (P450 aromatase) and thecal cells (P450 17alpha-hydroxylase). Experiment 2 examined the pattern of inhibin A production, in relation to oestradiol, by granulosa cells induced to differentiate in vitro with follicle-stimulating hormone (FSH). Experiment 3 examined possible paracrine and autocrine actions of inhibin A by determining the effect of addition of human recombinant inhibin A and/or antiserum to inhibin on gonadotrophin-stimulated cellular differentiation. The results of Experiment 1 showed that expression of mRNA encoding inhibin subnuits alpha, beta(A) and beta(B) is greater (P<0.05) in large oestrogenic follicles than in small follicles but that only expression of the inhibin beta(A) subunit differs (P<0.05) between large oestrogenic and non-oestrogenic follicles. Expression of 17alpha-hydroxylase, but not of the luteinising hormone (LH) receptor, in thecal cells was related to both the size and the oestrogenicity of antral follicles, in a manner similar to that of the inhibin subunits. Experiment 2 demonstrated that the production of inhibin A by sheep granulosa cells is FSH-responsive after prolonged exposure (P<0.001) and precedes the production of oestradiol by around 48 h in the differentiative cascade induced in granulosa cells by FSH. The results of Experiment 3 showed that inhibin A can augment gonadotrophin-stimulated steroid production by both granulosa and theca cells (P<0.01), and that the addition of antiserum to inhibin can inhibit FSH-stimulated oestradiol production by granulosa cells from both small and large follicles (P<0.001). We conclude that inhibin A is an FSH-responsive marker of granulosa cell differentiation which has both autocrine and paracrine actions in sheep.


Reproduction ◽  
2003 ◽  
pp. 683-691 ◽  
Author(s):  
AG Hernandez ◽  
JM Bahr

In chicken ovaries, one small yellow follicle (SYF) is selected daily from a pool of follicles of similar size and becomes a preovulatory follicle. FSH induces follicular growth and steroidogenesis. Epidermal growth factor (EGF), an intraovarian hormone, suppresses granulosa cell differentiation. This study demonstrates that recruitment of SYFs into the hierarchy of preovulatory follicles is associated with a change in steroidogenic activity in granulosa cells regulated, at least in part, by FSH and EGF. Abundance of P450 side-chain cleavage (P450scc) mRNA was higher in the smallest preovulatory follicle (F6) compared with SYF, whereas FSH and EGF receptor (FSHr and EGFr, respectively) mRNA abundance was similar. FSH increased P450scc mRNA abundance and progesterone secretion and decreased FSHr mRNA in cultured granulosa cells, whereas EGF attenuated or suppressed P450scc mRNA and decreased FSHr mRNA abundance. None of the hormones influenced EGFr mRNA abundance. When used in combination, EGF attenuated or suppressed the stimulatory effect of FSH on the expression of P450scc mRNA and production of progesterone in a dose-dependent manner. The results indicate that (1) selection is associated with an increase in P450scc mRNA; (2) FSH stimulates expression of P450scc mRNA and progesterone secretion in granulosa cells of SYF; and (3) induction of P450scc mRNA and progesterone secretion by FSH is attenuated or blocked by EGF.


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