scholarly journals Temporal and hormonal regulation of inhibin protein and subunit mRNA expression by post-natal and immature rat ovaries

2000 ◽  
Vol 166 (2) ◽  
pp. 339-354 ◽  
Author(s):  
AE Drummond ◽  
M Dyson ◽  
E Thean ◽  
NP Groome ◽  
DM Robertson ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Cell Cultures ◽  
Granulosa Cells ◽  
Inhibin B ◽  
Alpha Subunit ◽  
Inhibin A ◽  
Preantral Follicles ◽  
Subunit Mrna ◽  
Ovarian Cells ◽  
Old Rats

The contribution of specific follicle populations to dimeric inhibin production and inhibin subunit mRNA expression by the rat ovary has been investigated in two model systems, granulosa cells isolated from 25-day-old diethylstilboestrol (DES)-treated rats and post-natal rat ovaries, dispersed in culture or whole ovaries, using specific two-site immunoassays and 'real time' PCR. Media from FSH-stimulated granulosa cell cultures fractionated by gel filtration and RP-high performance liquid chromatography revealed two predominant peaks of alpha subunit activity which were attributed to alpha subunit and 31 k dimeric inhibin-A. The corresponding inhibin-B levels were low. FSH stimulation did not alter the ratio of inhibin-A:alpha subunit produced by granulosa cells. All three inhibin subunit mRNAs were expressed by granulosa cells, with eight-fold more alpha subunit mRNA relative to either of the beta subunits. Administration of DES to immature rats prior to the isolation of granulosa cells from the ovary led to beta(A) and beta(B) mRNA expression being down-regulated in the absence of any significant change in alpha subunit expression by the granulosa cells. Inhibin-A, -B and -alpha subunit were produced by basal and stimulated cultures of ovarian cells prepared from 4-, 8- and 12-day-old rats, indicating that primary, preantral and antral follicles contribute to total inhibin production. Consistent with these results, follicles within these ovaries expressed all three inhibin subunit mRNAs, with maximal expression observed in the ovaries of 8-day-old rats. The appearance of antral follicles in the ovary at day 12 led to a decline in the mRNA levels of each of the subunits but was most evident for the beta subunits. There was a profound influence of secondary preantral follicles on dimeric inhibin-A production, with FSH stimulation increasing inhibin-A relative to alpha subunit levels in cultures of ovarian cells prepared from 8-day-old rats. Thus, preantral follicles exposed to FSH contribute significantly to beta(A) subunit production by the ovary. In contrast, primary and preantral follicles did not produce inhibin-B in response to FSH stimulation. Transforming growth factor-beta (TGF-beta) enhanced, in a time-dependent manner, the production of the inhibin forms by ovarian cells in culture, although inhibin-B production was not responsive until day 8. The simultaneous treatment of ovarian cell cultures with FSH and TGF-beta elicited the greatest increases in production of all the inhibin forms. In summary, ovaries of 4-, 8- and 12-day-old rats expressed inhibin subunit mRNAs and produced dimeric inhibin-A and -B and free alpha subunit. Preantral follicles (day-8 ovarian cell cultures) were particularly sensitive to stimulation by FSH and TGF-beta and had a substantial capacity for inhibin production. The production of oestrogen by follicles may be instrumental in regulating inhibin production given that beta subunit mRNA expression was down-regulated by DES. The mechanisms by which inhibin-A and inhibin-B are individually regulated are likely to be similar during the post-natal period, when folliculogenesis is being established, and diverge thereafter, when inhibin-A becomes the predominant form in the fully differentiated ovary.

206. Differential regulation of activin and inhibin production by interleukin 1 (IL1), transforming growth factor β1 (TGFβ1) and protein kinase C (PKC) in the Sertoli cell and granulosa cell

2008 ◽  
Vol 20 (9) ◽  
pp. 6 ◽  
Author(s):  
V. Eede ◽  
J. A. Muir ◽  
A. E. O. 'Connor ◽  
W. R. Winnall ◽  
A. E. Drummond ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Sertoli Cell ◽  
Granulosa Cells ◽  
Sertoli Cells ◽  
Activin A ◽  
Inhibin B ◽  
Inhibin A ◽  
Α Subunit ◽  
Subunit Mrna ◽  
Subunit Expression

Activin and inhibin are gonadal regulatory proteins comprising an α-subunit and either a βA-subunit or βB-subunit (inhibin A or B), or two βA-subunits (activin A). Synthesis of the α-subunit, and the inhibins, is regulated by FSH via cAMP/protein kinase A. Regulation of the β-subunits in the gonads is less well defined, but the IL1/MAP kinase, TGFβ /Smad and PKC pathways have been implicated. Sertoli cells and granulosa cells were isolated from 18–22 day-old Sprague-Dawley rats under standard conditions and cultured with IL1, TGFβ1 and the PKC agonists, gonadotrophin releasing hormone (GnRH) or phorbol myristate acetate (PMA). Activin A, inhibin A and inhibin B were measured in culture medium (at 48h) by ELISA. Subunit mRNA expression was measured in cell extracts (at 4 h and 8h) using quantitative RT–PCR. IL1 stimulated βA-subunit and activin A production and inhibited α-subunit and βB-subunit expression and inhibin B production in Sertoli cells, but had no effect in granulosa cells. TGFβ1 stimulated activin A in both cell types, as well as the inhibins in granulosa cells. Surprisingly, TGFβ1 had no effect on Sertoli cell α-subunit or βA-subunit mRNA expression, but did cause a slight reduction of βB-subunit expression. GnRH increased activin A and inhibin A, but not inhibin B, production by granulosa cells and had no effect on Sertoli cells, which lack the GnRH receptor. However, direct activation of PKC by PMA stimulated βA-subunit mRNA expression and activin A production and decreased βB-subunit and inhibin B production by Sertoli cells, with marginal effects on inhibin A. These results indicate that activation of the TGFβ or PKC signalling pathways preferentially stimulates βA-subunit expression and/or translation, leading to increased activin A secretion by Sertoli cells and both activin A and inhibin A secretion by granulosa cells. The ability of IL1 to stimulate activin A is confined to the Sertoli cell.

scholarly journals Pachytene spermatocytes in co-culture inhibit rat Sertoli cell synthesis of inhibin beta B-subunit and inhibin B but not the inhibin alpha-subunit

2002 ◽  
Vol 172 (3) ◽  
pp. 565-574 ◽  
Author(s):  
RJ Clifton ◽  
L O'Donnell ◽  
DM Robertson
Keyword(s):  
Mrna Expression ◽  
Sertoli Cell ◽  
Sertoli Cells ◽  
Inhibin B ◽  
Alpha Subunit ◽  
Subunit Mrna ◽  
B Subunit ◽  
Subunit Expression ◽  
Pachytene Spermatocytes

This study investigates the effects of spermatogenic germ cells on inhibin alpha-subunit and beta B-subunit expression, and inhibin alpha-subunit and inhibin B production by rat Sertoli cells in vitro. Sertoli cells isolated from 19-day-old rats were cultured for 48 h at 32 degrees C, in the presence or absence of FSH (2.3-2350 mIU/ml), and in the presence of pachytene spermatocytes, round spermatids or cytoplasts of elongated spermatids purified from adult rat testis by elutriation and density gradient separation. Sertoli cell secretion of inhibin alpha-subunit and inhibin B, as measured by immunoassay, was dose-dependently stimulated by FSH (maximal stimulation 13- and 2-fold, respectively). Round spermatids or cytoplasts co-cultured with Sertoli cells had no effect on basal or FSH-induced secretion of inhibin alpha-subunit or inhibin B. When Sertoli cells were co-cultured with pachytene spermatocytes, inhibin alpha-subunit secretion was unaltered, while inhibin B secretion was suppressed in a cell concentration-dependent manner to reach a maximal suppression of 45% compared with Sertoli cells alone (P<0.01). A similar suppression in inhibin B was still observed (64% of Sertoli cells alone) when the pachytene spermatocytes were separated from Sertoli cells by a 0.45 microm pore membrane barrier in bicameral chambers. Pachytene spermatocytes also suppressed FSH-induced inhibin B levels in Sertoli cell co-cultures and this suppression was attributed to a decrease in basal inhibin B production rather than a change in FSH responsiveness. Quantitation of Sertoli cell inhibin alpha- and beta B-subunit mRNA by quantitative (real-time) PCR demonstrated that pachytene spermatocytes did not alter Sertoli cell alpha-subunit mRNA expression, but significantly (P<0.01) suppressed basal and FSH-induced beta B-subunit mRNA expression to a similar degree to that seen with inhibin B protein levels. It is concluded that pachytene spermatocytes in vitro suppress Sertoli cell inhibin B secretion via factor-mediated suppression of inhibin beta B-subunit expression. These findings support the hypothesis that specific germ cell types can influence inhibin B secretion by the testis independent of FSH regulation.

scholarly journals Growth Differentiation Factor-9 Stimulates Inhibin Production and Activates Smad2 in Cultured Rat Granulosa Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Jae-Sook Roh ◽  
Jonas Bondestam ◽  
Sabine Mazerbourg ◽  
Noora Kaivo-Oja ◽  
Nigel Groome ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Granulosa Cells ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Inhibin B ◽  
Inhibin A ◽  
Differentiation Factor ◽  
Growth Differentiation Factor 9 ◽  
Ovarian Inhibin ◽  
Stimulation Of

Abstract Ovarian inhibin production is stimulated by FSH and several TGFβ family ligands including activins and bone morphogenetic proteins. Growth differentiation factor-9 (GDF-9) derived by the oocyte is a member of the TGFβ/activin family, and we have previously shown that GDF-9 treatment stimulates ovarian inhibin-α content in explants of neonatal ovaries. However, little is known about GDF-9 regulation of inhibin production in granulosa cells and downstream signaling proteins activated by GDF-9. Here, we used cultured rat granulosa cells to examine the influence of GDF-9 on basal and FSH-stimulated inhibin production, expression of inhibin subunit transcripts, and the GDF-9 activation of Smad phosphorylation. Granulosa cells from small antral follicles of diethylstilbestrol-primed immature rats were cultured with FSH in the presence or absence of increasing concentrations of GDF-9. Secreted dimeric inhibin A and inhibin B were quantified using specific ELISAs, whereas inhibin subunit RNAs were analyzed by Northern blotting using 32P-labeled inhibin subunit cDNA probes. Similar to FSH, treatment with GDF-9 stimulated dose- and time-dependent increases of both inhibin A and inhibin B production. Furthermore, coincubation of cells with GDF-9 and FSH led to a synergistic stimulation of both inhibin A and inhibin B production. GDF-9 treatment also increased mRNA expression for inhibin-α and inhibin-β subunits. To investigate Smad activation, granulosa cell lysates were analyzed in immunoblots using antiphosphoSmad1 and antiphosphoSmad2 antibodies. GDF-9 treatment increased Smad2, but not Smad1, phosphorylation with increasing doses of GDF-9 leading to a dose-dependent increase in phosphoSmad2 levels. To further investigate inhibin-α gene promoter activation by GDF-9, granulosa cells were transiently transfected with an inhibin-α promoter-luciferase reporter construct and cultured with different hormones before assaying for luciferase activity. Treatment with FSH or GDF-9 resulted in increased inhibin-α gene promoter activity, and combined treatment with both led to synergistic increases. The present data demonstrate that oocyte-derived GDF-9, alone or together with pituitary-derived FSH, stimulates inhibin production, inhibin subunit mRNA expression, and inhibin-α promoter activity by rat granulosa cells. The synergistic stimulation of inhibin secretion by the paracrine hormone GDF-9 and the endocrine hormone FSH could play an important role in the feedback regulation of FSH release, thus leading to the modulation of follicle maturation and ovulation.

scholarly journals Reciprocal regulation of activin A and inhibin B by interleukin-1 (IL-1) and follicle-stimulating hormone (FSH) in rat Sertoli cells in vitro

2005 ◽  
Vol 185 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Y Okuma ◽  
K Saito ◽  
A E O’Connor ◽  
D J Phillips ◽  
D M de Kretser ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Sertoli Cells ◽  
Interleukin 1 ◽  
Activin A ◽  
Inhibin B ◽  
Dibutyryl Camp ◽  
Inhibin A ◽  
Reciprocal Regulation ◽  
Α Subunit ◽  
Subunit Mrna

In several biological systems, the inhibin βA homodimer activin A is stimulated by, and in turn, inhibits the action of interleukin (IL)-1 (both IL-1α and IL-1β) and IL-6. The possibility that a similar regulatory relationship operates within the testis was investigated. Sertoli cells from immature (20-day-old) rats were cultured with human IL-1α or IL-1β, human IL-6 and/or ovine FSH or dibutyryl cAMP. Activin A and the inhibin dimers, inhibin A and inhibin B, were measured by specific ELISA. Immunoreactive inhibin (ir-inhibin) was measured by RIA. Activin/inhibin subunit mRNA expression was measured by quantitative real-time PCR. Both IL-1 isoforms, but not IL-6, stimulated activin A secretion through increased synthesis of βA-subunit mRNA. IL-1 also stimulated activin A secretion by testicular peritubular cells. In contrast to the effect on activin A, IL-1 suppressed inhibin βB-subunit and, to a lesser extent, α-subunit mRNA expression, thereby reducing basal and FSH-stimulated inhibin B secretion by the Sertoli cells. Conversely, FSH inhibited basal activin A secretion and antagonised the stimulatory effects of IL-1. Dibutyryl cAMP partially inhibited the action of IL-1 on activin A secretion, but had no significant effect on basal activin A secretion. Secretion of inhibin A was low in all treatment groups. These data demonstrate that IL-1 and FSH/cAMP exert a reciprocal regulation of activin A and inhibin B synthesis and release by the Sertoli cell, and suggest a role for activin A as a potential feedback regulator of IL-1 and IL-6 activity in the testis during normal spermatogenesis and in inflammation.

Effect of cortisol on neurophysin I/oxytocin and peptidyl glycine-α-amidating mono-oxygenase mRNA expression in bovine luteal and granulosa cells

2013 ◽  
Vol 16 (2) ◽  
pp. 231-239
Author(s):  
A. Ziolkowska ◽  
J. Mlynarczuk ◽  
J. Kotwica
Keyword(s):  
Mrna Expression ◽  
Granulosa Cells ◽  
Molecular Mechanisms ◽  
Hormone Secretion ◽  
Oestrous Cycle ◽  
Luteal Cells ◽  
Ru 486 ◽  
Ovarian Cells ◽  
Key Genes ◽  
Ovary Function

Abstract Cortisol stimulates the synthesis and secretion of oxytocin (OT) from bovine granulosa and luteal cells, but the molecular mechanisms of cortisol action remain unknown. In this study, granulosa cells or luteal cells from days 1-5 and 11-15 of the oestrous cycle were incubated for 4 or 8 h with cortisol (1x10-5, 1x10-7 M). After testing cell viability and hormone secretion (OT, progesterone, estradiol), we studied the effect of cortisol on mRNA expression for precursor of OT (NP-I/OT) and peptidyl glycine-α-amidating mono-oxygenase (PGA). The influence of RU 486 (1x10-5 M), a progesterone receptor blocker and inhibitor of the glucocorticosteroid receptor (GR), on the expression for both genes was tested. Cortisol increased the mRNA expression for NP-I/OT and PGA in granulosa cells and stimulated the expression for NP-I/OT mRNA in luteal cells obtained from days 1-5 and days 11-15 of the oestrous cycle. Expression for PGA mRNA was increased only in luteal cells from days 11-15 of the oestrous cycle. In addition, RU 486 blocked the cortisol-stimulated mRNA expression for NP-I/OT and PGA in both types of cells. These data suggest that cortisol affects OT synthesis and secretion in bovine ovarian cells, by acting on the expression of key genes, that may impair ovary function.

scholarly journals Effect of sialylation and complexity of FSH oligosaccharides on inhibin production by granulosa cells

Reproduction ◽  
2013 ◽  
Vol 145 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Nazareth Loreti ◽  
Verónica Ambao ◽  
Luz Andreone ◽  
Romina Trigo ◽  
Ursula Bussmann ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Concanavalin A ◽  
Inhibin B ◽  
Inhibin A ◽  
Biological Responses ◽  
Immature Rats ◽  
Fold Stimulation ◽  
Recombinant Human Fsh

Granulosa cell (GC) inhibin A and B production is regulated by FSH and gonadal factors. This gonadotrophin is released as a mixture of glycoforms, which induce different biological responses in vivo and in vitro. Our aim was to determine the effect of recombinant human FSH (rhFSH) glycosylation variants on inhibin A and B production by rat GCs. Preparative isoelectro focusing was used to isolate more acidic/sialylated (pH <4.00) and less acidic/sialylated (pH >5.00) rhFSH charge analogues. Concanavalin A was used to isolate unbound and firmly bound rhFSH glycoforms on the basis of their oligosaccharide complexity. GCs, obtained from oestrogen-primed immature rats, were cultured with either native rhFSH or its glycosylation variants. Inhibin A and B were determined using specific ELISAs. Results were expressed as mean±s.e.m. Under basal conditions, inhibin A was the predominant dimer produced (inhibin A: 673±55; inhibin B: 80±4 pg/ml). More acidic/sialylated charge analogues stimulated inhibin B production when compared to inhibin A at all doses studied; by contrast, less acidic/sialylated charge analogues stimulated inhibin A production and elicited no effect on inhibin B. Glycoforms bearing complex oligosaccharides showed a potent stimulatory effect on inhibin B when compared to inhibin A production (i.e. dose 1 ng/ml: 4.9±0.5 vs 0.9±0.1-fold stimulation, P<0.001). Glycoforms bearing hybrid-type oligosaccharides favoured inhibin A production (i.e. dose 4 ng/ml 2.9±0.1 vs 1.6±0.1-fold stimulation, P<0.05). These results show that the sialylation degree as well as the complexity of oligosaccharides present in the rhFSH molecule may be considered additional factors that differentially regulate dimeric inhibin production by rat GCs.

Expression and regulation of high mobility group AT-hook 1 (HMGA1) during ovulation and luteinisation in rat ovary

2019 ◽  
Vol 31 (4) ◽  
pp. 698 ◽  
Author(s):  
Hao-ran Li ◽  
Yan Li ◽  
Yu Liu ◽  
Jiao-jiao Yu ◽  
Fei-xue Li
Keyword(s):  
Mrna Expression ◽  
Granulosa Cell ◽  
Cell Cultures ◽  
Granulosa Cells ◽  
In Situ Hybridisation ◽  
High Mobility ◽  
High Mobility Group ◽  
Female Rats ◽  
Corpora Lutea ◽  
Hmga1 Expression

High mobility group AT-hook 1 (HMGA1) is able to regulate gene expression and function as a tumour suppressor. The spatiotemporal expression pattern of HMGA1 was investigated in this study. Immature female rats (22–23 days old) were treated with 10IU, s.c., pregnant mare’s serum gonadotrophin to stimulate follicular development, followed 48h later by injection with 5IU, s.c., human chorionic gonadotrophin (hCG). Whole ovaries or granulosa cells were collected at various times after hCG administration (n=3 per time point). Real-time polymerase chain reaction and western blot analysis revealed that HMGA1 was highly stimulated in the ovary by 4–12h after hCG treatment. In situ hybridisation analysis demonstrated that Hmga1 mRNA expression was induced in granulosa cells between 8 and 12h after hCG treatment. There was negligible Hmga1 mRNA signal observed in newly forming corpora lutea. In addition, the data indicated that both the protein kinase (PK) A and PKC pathways regulated Hmga1 expression in rat granulosa cells. In rat granulosa cell cultures, upregulation of Hmga1 was dependent on new protein synthesis because Hmga1 was inhibited by cycloheximide. Furthermore, Hmga1 mRNA expression in rat granulosa cell cultures was inhibited by AG1478, whereas NS398 and RU486 had no effect, suggesting that Hmga1 expression was regulated, in part, by the epidermal growth factor pathway. In summary, the findings of this study suggest that induction of Hmga1 may be important for theca and granulosa cell differentiation into luteal cells.

scholarly journals Bone morphogenetic protein-6 enhances gonadotrophin-dependent progesterone and inhibin secretion and expression of mRNA transcripts encoding gonadotrophin receptors and inhibin/activin subunits in chicken granulosa cells

Reproduction ◽  
2007 ◽  
Vol 134 (2) ◽  
pp. 293-306 ◽  
Author(s):  
Sara L Al-Musawi ◽  
Richard T Gladwell ◽  
Philip G Knight
Keyword(s):  
Bone Morphogenetic Protein ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Cell Function ◽  
Dependent Manner ◽  
Cell Type ◽  
Inhibin A ◽  
Theca Cells ◽  
Subunit Mrna ◽  
Morphogenetic Protein

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.

scholarly journals Thrombopoietin regulates proliferation, apoptosis, secretory activity and intracellular messengers in porcine ovarian follicular cells: involvement of protein kinase A

2004 ◽  
Vol 183 (3) ◽  
pp. 595-604 ◽  
Author(s):  
A V Sirotkin ◽  
P Sanislo ◽  
H-J Schaeffer ◽  
I Florkovičová ◽  
J Kotwica ◽  
...  
Keyword(s):  
Growth Factor ◽  
Ovarian Function ◽  
Secretory Activity ◽  
Inhibin B ◽  
Inhibin A ◽  
Ovarian Cells ◽  
Intracellular Messengers ◽  
Igf I ◽  
Kinase A ◽  
Igfbp 3

Thrombopoietin (TPO) is known to be involved in megakariocytopoesis, but its role in the control of ovarian function is unknown. The aims of this study were to determine whether TPO can regulate the proliferation, apoptosis and secretory activity of ovarian cells, to identify possible intracellular mediators of TPO action, especially protein kinase A (PKA), and to define their interrelationships within ovarian cells. We investigated the effect of TPO treatment (0, 1, 10 or 100 ng/ml) on the following characteristics of cultured porcine ovarian follicles, determined using SDS-PAGE and Western blotting, immunocytochemistry, RIA and ELISA: the expression of intracellular peptides associated with proliferation (PCNA), apoptosis (Bax), tyrosine kinase (TK, phosphotyrosine), Cdc2/p34 kinase, PKA and the transcription factor CREB-1, and the secretion of progesterone, androstenedione, estradiol-17β, oxytocin, inhibin A, inhibin B, IGF-I, transforming growth factor-2β (TGF-2β) and IGF-binding protein 3 (IGFBP-3). The involvement of PKA-dependent pathways was examined by evaluating the effect of a PKA blocker (KT5720, 1 μg/ml), either alone or in combination with TPO, on the parameters listed above. A TPO-induced increase in expression of PCNA, Bax, PKA, TK, Cdc2/p34 and CREB was observed. Furthermore, TPO was able to inhibit androstenedione, estradiol, TGF-2β and IGFBP-3 secretion, and to stimulate oxytocin, inhibin A, inhibin B and IGF-I secretion. Progesterone secretion was not stimulated. The PKA blocker KT5720, when given alone, reduced the expression of Bax and TGF-2β, augmented the expression of PKA, CREB and oxytocin, but did not influence the secretion of progesterone, androstenedione, estradiol, IGFBP-3, inhibins A and B or IGF-I. When given together with TPO, the PKA blocker prevented or reversed the action of TPO on PKA, CREB, androstenedione, estradiol, IGFBP-3, oxytocin, but not its effect on Bax, TGF-2β or inhibin B. On the other hand, treatment with KT5720 augmented the effect of TPO on progesterone, inhibin A and IGF-I. These results provide the first evidence that TPO may be a potent regulator of ovarian function (e.g. proliferation, apoptosis and the secretion of peptide hormones, steroids, growth factors and growth factor-binding protein, as well as of the expression of some intracellular messengers). Furthermore, they demonstrated the importance of PKA in controlling these functions and in mediating the effects of TPO on ovarian cells. It remains possible that other (TK- and Cdc2/p34-dependent) intracellular mechanisms are also involved in mediating TPO action on the ovary.

Effects of FSH and testosterone on highly purified rat Sertoli cells: inhibin α-subunit mRNA expression and inhibin secretion are enhanced by FSH but not by testosterone

1989 ◽  
Vol 122 (3) ◽  
pp. 757-762 ◽  
Author(s):  
A. M. W. Toebosch ◽  
D. M. Robertson ◽  
I. A. Klaij ◽  
F. H. de Jong ◽  
J. A. Grootegoed
Keyword(s):  
Mrna Expression ◽  
Effective Dose ◽  
Sertoli Cell ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Osmotic Shock ◽  
Shock Treatment ◽  
Α Subunit ◽  
Subunit Mrna ◽  
Old Rats

ABSTRACT The effects of FSH and testosterone on inhibin mRNA expression and inhibin production by highly purified Sertoli cell preparations were examined. Sertoli cells were isolated from testes of 22-day-old rats by sequential trypsin, collagenase and hyaluronidase treatments, with subsequent osmotic shock treatment on day 3 of culture. Contamination by peritubular and germ cells was <0·5 and 1–3% respectively. Intracellular and secreted inhibin levels were measured by radioimmunoassay, using Sertoli cells which were incubated for 24 h in the absence or presence of FSH and testosterone from days 4 to 5 of culture. FSH stimulated the cellular inhibin content and the secreted inhibin level by four- and sevenfold respectively, with a half-maximal effective dose of 5–50 ng/ml. Under the present incubation conditions, testosterone (1 μmol/l) had no effect on immunoreactive inhibin levels in either the presence or absence of FSH. Similarly, the expression of inhibin α-subunit mRNA was increased following FSH stimulation, whereas testosterone had no effect. The expression of inhibin βB-subunit mRNAs was not influenced by FSH or testosterone. It is concluded that highly purified Sertoli cell preparations, with a very low number of peritubular or germ cells, are fully responsive to FSH with respect to inhibin mRNA expression and inhibin production. Journal of Endocrinology (1989) 122, 757–762

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