TY - JOUR
T1 - The insulin-like growth factor, somatomedin C, induces the synthesis of cholesterol side-chain cleavage cytochrome P-450 and adrenodoxin in ovarian cells
AU - Veldhuis, Johannes D
AU - Rodgers, R. J.
AU - Dee, A.
AU - Simpson, E. R.
PY - 1986
Y1 - 1986
N2 - The actions of insulin and somatomedin C (insulin-like growth factor I) on cholesterol side-chain cleavage activity and the synthesis of cytochrome P-450(scc) and adrenodoxin were investigated in primary cultures of swine ovarian (granulosa) cells. Nanomolar concentrations of pure human somatomedin C stimulated biosynthesis of progesterone and 20α-hydroxypregn-4-en-3-one. Moreover, in the presence of exogenous sterol substrate for cholesterol side-chain cleavage, somatomedin C significantly enhanced pregnenolone biosynthesis in a time- and dose-dependent manner. This augmentation of functional cholesterol side-chain cleavage activity was accompanied by a dose-dependent (2-16-fold) increase in [35S]methionine incorporation into specific immunoprecipitable cytochrome P-450(scc) and adrenodoxin. Micromolar concentrations of insulin (but not proinsulin or desoctapeptide) also induced synthesis of cholesterol side-chain cleavage constitutents by 4-7-fold. These results demonstrate that an insulin-like growth factor, somatomedin C, exerts discrete differentiating effects on ovarian cells characterized by increased synthesis of immunospecific cytochrome P-450(scc) and adrenodoxin. Thus, we infer that somatomedin C may serve a critical role in the differentiation of steroidogenic cells in the mammalian ovary.
AB - The actions of insulin and somatomedin C (insulin-like growth factor I) on cholesterol side-chain cleavage activity and the synthesis of cytochrome P-450(scc) and adrenodoxin were investigated in primary cultures of swine ovarian (granulosa) cells. Nanomolar concentrations of pure human somatomedin C stimulated biosynthesis of progesterone and 20α-hydroxypregn-4-en-3-one. Moreover, in the presence of exogenous sterol substrate for cholesterol side-chain cleavage, somatomedin C significantly enhanced pregnenolone biosynthesis in a time- and dose-dependent manner. This augmentation of functional cholesterol side-chain cleavage activity was accompanied by a dose-dependent (2-16-fold) increase in [35S]methionine incorporation into specific immunoprecipitable cytochrome P-450(scc) and adrenodoxin. Micromolar concentrations of insulin (but not proinsulin or desoctapeptide) also induced synthesis of cholesterol side-chain cleavage constitutents by 4-7-fold. These results demonstrate that an insulin-like growth factor, somatomedin C, exerts discrete differentiating effects on ovarian cells characterized by increased synthesis of immunospecific cytochrome P-450(scc) and adrenodoxin. Thus, we infer that somatomedin C may serve a critical role in the differentiation of steroidogenic cells in the mammalian ovary.
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M3 - Article
C2 - 3753972
AN - SCOPUS:0023001697
VL - 261
SP - 2499
EP - 2502
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 6
ER -