Michael Waterman
Faculty Member
Last active: 2/12/2015

Induction of 17 alpha-hydroxylase (cytochrome P-450(17)alpha) activity by adrenocorticotropin in bovine adrenocortical cells maintained in monolayer culture.

McCarthy JL, Kramer RE, Funkenstein B, Simpson ER, Waterman MR
Arch Biochem Biophys. 1983 222 (2): 590-8

PMID: 6303224 · DOI:10.1016/0003-9861(83)90557-x

Using bovine adrenocortical cells in monolayer culture it has been shown that treatment with adrenocorticotropin (ACTH) causes a dramatic increase in 17 alpha-hydroxylase activity. In postmitochondrial supernatant fractions (PMS) prepared from cells maintained in culture, there was a 15-fold increase in 17 alpha-hydroxylase activity 36 h following initiation of ACTH treatment compared with the activity measured in PMS prepared from control cells. In the continued presence of ACTH, 17 alpha-hydroxylase activity declined; however, even after 60 h of exposure to ACTH, 17 alpha-hydroxylase activity was eight times higher than that present in control cells. The dramatic increase in 17 alpha-hydroxylase activity provides an explanation for the previously observed phenomenon that following initiation of ACTH treatment of bovine adrenocortical cells in monolayer culture there is a shift in the pattern of corticosteroid secretion from approximately equal amounts of cortisol and corticosterone to almost exclusively cortisol. Thus, the modulation of 17 alpha-hydroxylase activity by ACTH action appears to serve a key regulatory role in the pattern of corticosteroid production. Soluble cytosolic factors apparently do not participate in the regulation of 17 alpha-hydroxylase activity in the bovine adrenal cortex. Increases in the magnitude of substrate-induced absorbance changes are indicative that the increase in 17 alpha-hydroxylase activity is due, at least in part, to an elevation of cytochrome P-450(17)alpha synthesis.

MeSH Terms (11)

Adrenal Cortex Adrenocorticotropic Hormone Animals Cattle Cells, Cultured Corticosterone Cytochrome P-450 Enzyme System Enzyme Induction Hydrocortisone Steroid 17-alpha-Hydroxylase Steroid Hydroxylases

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