Gonadotropin and cAMP modulation of IGE binding protein production in ovarian granulosa cells

Grimes, Randall W.; Samaras, Susan; Barber, Joseph C.; Shimasaki, Shunichi; Ling, Nicholas; Hammond, James M.

doi:10.1152/ajpendo.1992.262.4.e497

Cited by 27 publications

(24 citation statements)

References 25 publications

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“…On the other hand, IGFBP-3 mRNA was found to be preferentially expressed in thecal cells [13], which agrees with our finding of predominant expression in small luteal cells in the current study. However, these data contrast with our in vitro observations [28][29][30][31], which indicate that porcine granulosa cells can secrete IGFBP-3 under some circumstances. Irrespective of the cell type involved, the present observations illustrate dramatic shifts in the type and amount of the IGFBP produced during luteinization.…”

Section: Igf-i Versus Igfbp-3 Mrna (Small and Large Cells)contrasting

confidence: 99%

Expression of the Messenger Ribonucleic Acids for Insulin-Like Growth Factor-I and Insulin-Like Growth Factor Binding Proteins in Porcine Corpora Lutea1

Gadsby

Lovdal

Samaras

et al. 1996

Biology of Reproduction

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In the pig, the corpus luteum (CL) can develop and function autonomous of pituitary gonadotropins for approximately 12 days. We hypothesized that the insulin-like growth factor (IGF) system may play an autocrine/paracrine luteotrophic role(s) during this period. In this study, we monitored the expression (i.e., steady-state levels of mRNAs) of IGF-I and IGF binding proteins (IGFBP)-2, -3, -4, -5, and -6 mRNAs in whole CL and in small and large luteal cells on Days 4-16 of the estrous cycle. CL were dissociated with collagenase, and large and small luteal cells were isolated by centrifugal elutriation. Whole CL and luteal cells were extracted to isolate total or poly(A)+ RNA, which was subjected to Northern and/or dot-blot analyses using [32P]-labeled cDNA probes for IGF-I and IGFBP-2, -3, -4, -5, and -6. Northern blots showed readily detectable transcripts for IGF-I (6.7 and 0.9 kb), IGFBP-2 (1.8 kb), IGFBP-3 (2.8 kb), IGFBP-4 (2.6 kb), and IGFBP-5 (6.0 kb), but not for IGFBP-6. IGFBP-3 and -5 transcripts were observed mainly in small luteal cells, while IGFBP-2 and -4 were seen in both cell types. Dot-blot analyses for IGF-I and IGFBP-3 mRNAs were performed on total RNA from small and large luteal cells; blots were counter-probed with 3-phosphoglyceraldehyde dehydrogenase (p-GAD) cDNA to assess RNA quantity and quality. IGF-I mRNA (ratio IGF-I:p-GAD mRNA) expression was approximately 2-fold greater in small than in large luteal cells on Days 4-10. However, steady-state levels of IGF-I mRNA in small, but not large, luteal cells decreased significantly on Days 12-16 (vs. Days 4-10). IGFBP-3 mRNA expression was significantly greater (approximately 3-fold) in small than in large luteal cells but did not vary significantly between Days 4-10 and 12-16 for either cell type. We conclude that porcine CL express mRNAs for IGF-I and IGFBP-2, -3, -4, and -5, and that while small luteal cells are the major sources of IGF-I and IGFBP-3 and -5, IGFBP-2 and -4 appear to be expressed to approximately the same extent in small and large luteal cells. These results further suggest that the IGF-I/IGF system may have autocrine/paracrine regulatory actions in CL development/function in the pig.

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Section: Igf-i Versus Igfbp-3 Mrna (Small and Large Cells)contrasting

confidence: 99%

Expression of the Messenger Ribonucleic Acids for Insulin-Like Growth Factor-I and Insulin-Like Growth Factor Binding Proteins in Porcine Corpora Lutea1

Gadsby

Lovdal

Samaras

et al. 1996

Biology of Reproduction

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“…Evaluation of the IGFBP profile in control and ACTH-treated gilts confirmed the presence of IGFBP-3 and IGFBP-2 in the FF of individual follicles. Both of these proteins have previously been detected in porcine FF and are known products of granulosa and luteal cells (Howard & Ford 1992, Grimes et al 1994. IGFBP-4 and -5 have also been measured in porcine FF, but were not detected in the current study, indicating that their concentrations are too low (in individual follicles) to be discerned with this method.…”

Section: Figurecontrasting

confidence: 55%

ACTH treatment disrupts ovarian IGF-I and steroid hormone production

Viveiros

Liptrap²

2000

Journal of Endocrinology

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Hyper-adrenal activity and increased glucocorticoid hormone release are associated with disruptions in reproductive function and adverse effects on the ovary. The aim of this investigation was to determine whether elevated glucocorticoid hormone levels can influence ovarian IGF-I synthesis and action in vivo. To elevate endogenous glucocorticoid levels, gilts were treated with ACTH during the luteal phase of the oestrous cycle (days 9-13) while the control group received saline. The gilts were subsequently ovariectomized on either day 14 or day 18 of the oestrous cycle. Follicular fluid (FF) was collected from individual follicles; IGF-I and steroid hormone concentrations were determined by radioimmunoassay, and IGF-binding protein (IGFBP) expression was assessed by Western ligand blotting. Granulosa cells were also recovered and placed in culture to determine IGF-I, progesterone (P 4 ) and oestradiol-17 (E 2 ) production levels. The cells were cultured in serum-free medium for 5 days and supplemented with: (a) media alone, (b) IGF-I, (c) FSH and androstenedione (A 4 ), or (d) IGF-I with FSH and A 4 . The FF from ACTH-treated gilts was characterized by elevated (P<0·05) cortisol levels on day 14 and lower (P<0·05) E 2 values on both day 14 and day 18. Lower (P<0·05) IGF-I concentrations were also measured in the FF of ACTH-treated gilts collected on day 18. This altered hormone profile in FF was associated with impaired IGF-I and steroid hormone synthesis by granulosa cells. IGFstimulated P 4 production (P<0·01) by cells recovered from ACTH-treated gilts on day 14 was lower (P<0·05). By day 18, IGF-I, P 4 and E 2 production by cells from the ACTH group were all significantly (P<0·05) lower. These results demonstrate that increased glucocorticoid concentrations can disrupt subsequent ovarian IGF-I synthesis and IGF action in vivo and can, potentially, impair follicle maturation.

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“…Using our method, we cannot exclude that a minor population of IGF-I binding in thecal cells and in apoptotic granulosa cells was due to specific receptors. Concerning IGFBPs in swine ovaries, the expression of IGFBP-2 and -4 mRNAs has been reported in granulosa and thecal cells throughout the follicular development (Zhou et al 1996), and the presence of IGFBP-2, -3 and -4 has been demonstrated in follicular fluid, IGFBP-2 being most related to atresia and IGFBP-3 to preovulatory maturation (Mondschein et al 1991, Grimes et al 1994.…”

Section: Discussionmentioning

confidence: 99%

Localization of binding sites for IGF-I, insulin and GH in the sow ovary

Quesnel¹

1999

Journal of Endocrinology

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Binding sites for IGF-I, insulin, and GH were localized by in situ binding of 125 I-labelled hormones to the different compartments of the sow ovary. Binding sites for IGF-I were detected in oocytes, granulosa and thecal cells of healthy and atretic follicles as well as in the antrum and the stroma. Competition of 125 I-labelled IGF-I with IGF-I, insulin and an analogue of IGF-I (Long R 3 IGF-I), which allowed discrimination between binding to binding proteins from binding to type-I receptors, suggested that type-I receptors were present in granulosa cells of healthy follicles, whilst binding in other compartments was mainly due to binding proteins. Binding of insulin was revealed in oocytes, granulosa and theca interna cells of healthy preantral and antral follicles, and, to a lesser extent, in theca externa and stromal cells, and was still observed in granulosa cells of atretic follicles. Labelling with 125 Ilabelled bovine GH was demonstrated in oocytes, granulosa cells, theca interna cells, and, although less intense, in theca externa and stromal cells. It disappeared in granulosa cells during atresia. Binding sites for GH were detected at all follicular stages, from preantral to preovulatory stages, but the intensity of labelling in granulosa cells was more intense in preantral than in large follicles. These data support the participation of insulin, GH and IGF-I in oocyte maturation, follicular growth and stromal cell function in swine.

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Gonadotropin and cAMP modulation of IGE binding protein production in ovarian granulosa cells

Cited by 27 publications

References 25 publications

Expression of the Messenger Ribonucleic Acids for Insulin-Like Growth Factor-I and Insulin-Like Growth Factor Binding Proteins in Porcine Corpora Lutea1

Expression of the Messenger Ribonucleic Acids for Insulin-Like Growth Factor-I and Insulin-Like Growth Factor Binding Proteins in Porcine Corpora Lutea1

ACTH treatment disrupts ovarian IGF-I and steroid hormone production

Localization of binding sites for IGF-I, insulin and GH in the sow ovary

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