Biosynthesis of Proteoglycans by Rat Granulosa Cells Cultured in Vitro: Modulation by Gonadotropins, Steroid Hormones, Prostaglandins, and a Cyclic Nucleotide

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Abstract
Rat ovarian granulosa cells were isolated from immature female rats 48 h after stimulation with 5 IU PMS gonadotropin and then maintained in culture. The effects of ovine (o)FSH, oLH, hCG, testosterone, 17β-estradiol, progesterone, prostaglandins E1, E2, F1α, F2α, N,O′-dibutyryl cAMP, and theophylline on proteoglycan synthesis by the granulosa cells in vitro were examined using [35S]sulfate as a precursor. oFSH, oLH, hCG, prostaglandins E1 and E2, N,O′-dibutyryl cAMP, theophylline and testosterone stimulated the production of 35Slabeled proteoglycans compared to control cultures. 17β-Estradiol, progesterone, and the prostaglandins F1α and F2α showed no stimulation. Two major species of proteoglycan are synthesized and secreted into the medium: 1) a population with large hydrodynamic size (Kav = 0.30 on Sepharose CL-2B); and 2) a population with relatively small size (Kav = 0.60 on Sepharose CL-2B). The stimulatory effect of the hormones was accounted for entirely by a net increase in synthesis of the smaller proteoglycan population. The hormones exert their stimulatory effects on proteoglycan synthesis at concentrations similar to those required for other in vitro biological responses of granulosa cells.

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