Somatomedin C augments FSH-induced differentiation of cultured rat granulosa cells

Davoren, J. B.; Hsueh, Ju-Ting; Li, C. H.

doi:10.1152/ajpendo.1985.249.1.e26

Cited by 54 publications

(36 citation statements)

References 26 publications

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“…That IGF-I synergizes with FSH in inducing LH receptors and enhances progesterone production in granulosa cells has been reported (23)(24)(25). These actions appear to be mediated by specific receptors on these cells.…”

Section: Discussionmentioning

confidence: 88%

Human pituitary and placental hormones control human insulin-like growth factor II secretion in human granulosa cells.

Ramasharma¹,

Li²

1987

Proc. Natl. Acad. Sci. U.S.A.

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Human granulosa cells cultured with calf serum actively proliferated for 18-20 generations and secreted progesterone into the medium; progesterone levels appeared to decline with increase in generation number. Cells cultured under serum-free conditions secreted significant amounts of progesterone and insulin-like growth factor II (IGF-H). The progesterone secretion was enhanced by the addition of human follitropin, lutropin, and chorionic gonadotropin but not by growth hormone. These cells, when challenged to varying concentrations of human growth hormone, human chorionic somatomammotropin, human prolactin, chorionic gonadotropin, follitropin, and lutropin, secreted IGF-H into the medium as measured by specific IGF-II RIA. Among these human hormones, chorionic gonadotropin, follitropin, and lutropin were most effective in inducing IGF-ll secretion from these cells. When synthetic lutropin-releasing hormone and c-inhibin-92 were tested, only lutropin-releasing hormone was effective in releasing IGF-II. The results described suggest that cultured human granulosa cells can proliferate and actively secrete progesterone and IGF-H into the medium. IGF-II production in human granulosa cells was influenced by a multi-hormonal complex including human growth hormone, human chorionic somatomammotropin, and prolactin.The insulin-like growth factors (IGF-I and IGF-II) are a family of low Mr single-chain peptides with considerable structural and functional similarities to proinsulin (1-3). These growth factors appear to follow a divergent pattern of regulatory mechanisms. The IGF-I levels in plasma are low at birth and gradually increase with age, thus closely following the actions of growth hormone (4-6). Conversely, IGF-II is considered a fetal hormone and appears partially dependent on growth hormone (7,8). Although the liver is considered the primary site of synthesis of these factors, recent studies have shown that several other tissues including the testes and the ovary (9-11) are also capable of producing IGFs.The exact role of IGFs in gonadal function is not clear. Attempts to demonstrate the production of IGF-I by cultured granulosa and Sertoli cell (12, 13) have been inconclusive. We have recently identified significant amounts of IGF-II in human follicular and seminal fluids (14). We report the production of IGF-II by human granulosa cells under serumfree conditions and present evidence for multihormonal regulation of IGF-II release by these cells. MATERIALS AND METHODSIGF-II was synthesized by the solid-phase method as described (15 (75 cm2) and 24-well culture plates were from Coming Glass Works.Human Granulosa Cell Cultures. Human follicular fluid was collected from women who were undergoing in vitro fertilization procedures at the Department of Obstetrics and Gynecology of this university. The cell culture method was essentially as reported (18,19), and briefly described as follows: Granulosa cells in the follicular fluid were pooled from different sized follicles and separated by centrifugation at 500...

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Section: Discussionmentioning

confidence: 88%

Human pituitary and placental hormones control human insulin-like growth factor II secretion in human granulosa cells.

Ramasharma¹,

Li²

1987

Proc. Natl. Acad. Sci. U.S.A.

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“…Alternatively, insulin at very high concentrations may act through the IGF-I receptor. Insulin-like growth factor-I will synergise with FSH to enhance steroid secretion from granulosa cells (Adashi et al 1984, 1985a, Davoren et al 1985, and with LH to stimulate androgen production from the theca (Erickson et al 1985, Cara & Rosenfield 1988, Morley et al 1989. If high concentrations of insulin were to activate the IGF-I receptor, enhanced steroid secretion would be expected.…”

Section: Discussionmentioning

confidence: 99%

The effect of a direct arterial infusion of insulin and glucose on the ovarian secretion rates of androstenedione and oestradiol in ewes with an autotransplanted ovary

Downing¹,

Joss²,

Scaramuzzi³

1999

Journal of Endocrinology

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Improving ewe nutrition even for short periods will increase ovulation rate. The increased nutrients must in some way affect the number of follicles that develop to the pre-ovulatory stage. One possible mechanism is that a nutrient or a metabolic hormone that responds to nutrition might act directly on the ovary to influence follicle development and/or follicle selection. In the study described here, insulin and glucose, alone or together, were infused directly into the ovarian artery of ewes with an autotransplanted ovary, for 13·5 h on day 11 of the oestrous cycle. The pattern of androstenedione and oestradiol secretion in response to a GnRH-stimulated LH pulse was measured 2·5 h before and 12·5 h and 24·5 h after the start of the infusion. Glucose or insulin infused alone had no effect on the secretion of androstenedione and oestradiol. However, when infused together, they decreased significantly the secretion of androstenedione and, to a lesser extent, oestradiol. We suggest that the sudden availability of additional glucose and insulin increases insulin-stimulated glucose uptake by the follicle. This leads to an inhibition of LH-stimulated steroidogenesis by the ovarian follicle which occurs in the absence of any detectable changes in circulating plasma concentrations of FSH. These results show that insulin and glucose act together to influence ovarian function directly and suggest that the effects of short-term nutrition on ovulation rate may be mediated by a direct ovarian action of insulin and glucose.

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“…IGF-1 acts via its receptor on the granulosa cells to enhance the FSH-induced stimulation of aromatase activity [41][42][43]. IGF-I also amplifies the synergism observed between FSH and testosterone in aromatase expression [38].…”

Section: 3a Factors Affecting Aromatase Expression In Granulosa Cellsmentioning

confidence: 99%

Aromatase expression in the ovary: Hormonal and molecular regulation

2008

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Summary-Estrogens are synthesized by the aromatase enzyme encoded by the Cyp19a1 gene, which contains an unusually large regulatory region. In most mammals, aromatase expression is under the control of two distinct promoters a gonad-and a brain-specific promoter. In humans, this gene contains 10 tissue-specific promoters that are alternatively used in various cell types and tumors. Each promoter is regulated by a distinct set of regulatory sequences and transcription factors that bind to these specific sequences. The cAMP/PKA/CREB pathway is considered to be the primary signaling cascade through which the gonad Cyp19 promoter is regulated. Very interestingly, in rat luteal cells, the proximal promoter is not controlled in a cAMP dependent manner. Strikingly, these cells express aromatase at high levels similar to those found in preovulatory follicles, suggesting that alternative and powerful mechanisms control aromatase expression in luteal cells and that the rat corpus luteum represents an important paradigm for understanding alternative controls of the aromatase gene. Here, the molecular and cellular mechanisms controlling the expression of the aromatase gene in granulosa and luteal cells are discussed.

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Somatomedin C augments FSH-induced differentiation of cultured rat granulosa cells

Cited by 54 publications

References 26 publications

Human pituitary and placental hormones control human insulin-like growth factor II secretion in human granulosa cells.

Human pituitary and placental hormones control human insulin-like growth factor II secretion in human granulosa cells.

The effect of a direct arterial infusion of insulin and glucose on the ovarian secretion rates of androstenedione and oestradiol in ewes with an autotransplanted ovary

Aromatase expression in the ovary: Hormonal and molecular regulation

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