| Abstrakt: |
THE most significant short term physiological effect of adrenocorticotrophic hormone (ACTH) is to increase the rate of adrenal steroid hormone synthesis and secretion1,2. There is a great deal of evidence for adenosine 3′,5′-monophosphate (cyclic AMP) as intracellular mediator of this acute steroidogenic response3–9. The following steps are probably involved2: ACTH increases adrenocortical adenyl cyclase activity, thus raising the intracellular concentration of cyclic AMP which in turn enhances the conversion of cholesterol to pregnenolone, normally the rate-limiting reaction. Much of the evidence for this concept comes from experiments on intact cells though the enhancement of a variety of steroid hydroxylations in cell-free adrenal preparations by cyclic AMP has been reported10–13. |
