Effect of prolonged infusions of angiotensin II on eight serum corticosteroids in man on different sodium diets.

The effects of long-term infusions of angiotensin II on serum progesterone, 17-OH-progesterone, deoxycorticosterone, corticosterone, 11-deoxycortisol, 18-OH-deoxycorticosterone, aldosterone and cortisol were studied in normal male subjects who were given normal or low sodium diets. While aldosterone levels exhibit the known marked increase during angiotensin II infusion, alterations of serum levels of the other steroids were absent or moderate. In the sodium replete state, an initial fall in 9 a.m. serum cortisol, 18-OH-deoxycorticosterone and corticosterone was followed by an increase of these steroids in the later phase of the infusion period. After Na+-restriction, however, a slight progressive increase of serum cortisol, 18-OH-deoxycorticosterone and corticosterone occurs after the onset of infusion. No changes of serum progesterone and 17-OH-progesterone are observed under sodium replete or low sodium conditions. These findings are tentatively explained by two mechanisms: 1) Angiotensin II has a "trophic" effect on the adrenal cortex, thus causing a progressive increase of secretion of corticosteroids in the normal sodium as well as in the low sodium state. 2) Angiotensin II may directly or indirectly inhibit ACTH secretion. This mechanism could be responsible for the initial fall of serum corticosteroids in the sodium replete state, while under low sodium conditions, this effect may be masked by the more pronounced mechanism.