Developmental Changes in Marmoset Granulosa Cell Responsiveness to Insulin-Like Growth Factor-I: Interactions with Follicle-Stimulating Hormone and Estradiol1
| Autor: | S E Boddy, J K Hodges, H J Shaw |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
endocrine system
medicine.medical_specialty medicine.drug_class Granulosa cell Ovary Cell Biology General Medicine Biology Follicle-stimulating hormone Endocrinology medicine.anatomical_structure Reproductive Medicine Cell culture Estrogen Internal medicine Follicular phase medicine biology.protein Aromatase Gonadotropin |
| Zdroj: | Biology of Reproduction. 49:568-576 |
| ISSN: | 1529-7268 0006-3363 |
| DOI: | 10.1095/biolreprod49.3.568 |
| Popis: | The biological actions of insulin-like growth factor-I (IGF-I) on granulosa cell steroidogenesis at defined stages of preovulatory follicular development in the marmoset monkey were examined. Studies were carried out by primary cell culture of granulosa cells derived from small antral (0.5-1-mm diameter) and large preovulatory (2-3-mm diameter) follicles collected during the mid-late follicular phase of the ovarian cycle. IGF-I (0.3-100 ng/ml) had no effect on progesterone accumulation or aromatase activity during 48-h culture of granulosa cells from small follicles. Progesterone accumulation by cells from large follicles was also unaffected by IGF-I over the same time period, although aromatase activity was stimulated in a dose-dependent manner (18-fold increase over basal levels with a maximally stimulatory dose of 30 ng IGF-I/ml). In contrast, granulosa cells from small and large follicles responded to IGF-I in terms of both progesterone accumulation and aromatase activity after longer periods of culture (4 days for progesterone; 6 days for aromatase). Concurrent treatment of granulosa cells from small follicles with estradiol (10 - 7 M) enhanced the dose-dependent actions of IGF-I on both indices of steroidogenesis and advanced the time at which IGF-I-stimulated activity was first detectable. The effects of estradiol on granulosa cell IGF-I responsiveness were independent of cell number. A synergistic action of IGF-I on FSH-stimulated granulosa cell steroidogenesis was not apparent. Co-incubation of cells from either follicle size category with increasing doses of IGF-1 (0.3-30 ng/ml) and a maximally stimulatory dose of FSH (5 ng/ml) resulted in no additional response (aromatase or progesterone accumulation) compared with that in the presence of FSH alone. Findings were similar for 2, 4, and 6 days of culture. Reciprocal treatment (i.e., maximally stimulatory dose of IGF-I, 30 ng/ml; range of suboptimal FSH doses, 0.01-1 ng/ml) indicated that the combined effects of the two treatments on aromatase activity in cells from large follicles were additive, while FSH-stimulated progesterone accumulation in cells from small follicles was inhibited by IGF-I. In summary, these results demonstrate varied actions of IGF-I on marmoset granulosa cell steroidogenesis in vitro. The data indicate that marmoset granulosa cells acquire responsiveness to IGF-I in terms of aromatase activity during follicular development in vivo and that estradiol can induce the response in vitro. The results also suggest that estrogen and progesterone biosynthesis by cultured marmoset granulosa cells is differentially regulated by IGF-I and that IGF-I and FSH do not appear to act synergistically in regulating steroidogenesis. Together, these results provide new insights into the biological action of IGF-I in the primate ovary. |
| Databáze: | OpenAIRE |
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