A Transhydrogenase and Reduced Triphosphopyridinenucleotide Involved in the Oxidation of Desoxycorticosterone to Corticosterone by Adrenal Tissue¹

Effect of Hypophysectomy on NADP and NADPH Concentration and Corticosteroid Secretion in the Rat Adrenal

“…A certain amount of indirect evidence has been presented which indicates that NADPH may be rate-limiting in the hydroxylation steps of steroid biosynthesis (5)(6)(7)(8)14). It has been suggested, further, that the actual rate of secretion of corticosteroids may be directly controlled by an ACTH-mediated regulation of the concentration of NADPH (13,14,20).…”

“…Only at the 216-hr period of observation is there a suggestive fall in NADP concentration, the p value for the 4 One unit is that amount of enzyme reducing 1.0 fiinole of NADP/min under the conditions of the assay. 5 One unit is that amount of enzyme oxidizing 0.5 jumole of NADH/min under the conditions of the assay. 6 One unit is that amount of enzyme reducing 4.8X10" 4 /xmoles of NAD/min under the conditions of the assay.…”

“…(Endocrinology 7 5 : 501,1964) A NUMBER of investigations have indicated that the synthesis of adrenal corticosteroids from acetate requires reductive energy in the form of NADPH. These major NADPH-requiring steps are: a) hydroxymethyl-glutaryl-CoA reduction to mevalonic acid (1, 2); b) squalene reduction to lanosterol (3); c) lanosterol conversion to cholesterol (4); and d) cholesterol hydroxylation and conversion in several steps to corticosteroids (5)(6)(7)(8)(9). In keeping with this high requirement for NADPH, Glock and McLean (10) and Kelley et al (11) have observed a very high level of both glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in adrenal tissue.…”

Mechanisms of Oxygen Metabolism

“…Oxygen is required for the reaction (288,332,333) ; competitive electron acceptors act as inhibitors (722,723).…”

Biological Activity of Fractions Obtained by Differential Centrifugation of the Bovine Adrenal Cortex

“…Beef adrenal fractions prepared by differential centriiugation have been investigated for their enzyme activity in steroid biosynthesis (1)(2)(3)(4)(5). It has not been established whether the particulate fractions contain active hormones which possess biological activity characteristic of that of known adrenocortical hormones or whether the active adrenocortical hormones are present only in the soluble portion of the cell with the granules contributing the enzymes for the formation of the hormones.…”