Oxytocin and arginine vasopressin stimulate steroid secretion by the isolated perfused rat adrenal gland.

Using the intact isolated perfused rat adrenal preparation we have shown for the first time a direct effect of oxytocin on adrenocortical steroid secretion. Oxytocin specifically stimulated aldosterone secretion in a dose-dependent manner with a threshold dose of 1 pmol. Arginine vasopressin was also shown to be a potent stimulus to aldosterone secretion and was additionally found to stimulate inner zone function. Using superfused adrenal cells, the effects of arginine vasopressin were only seen at 10,000 times higher doses than were effective in the intact perfused gland, and oxytocin had no effect at any dose. These results reinforce the hypothesis that tissue integrity is essential for full expression of steroidogenic control mechanisms. We conclude that oxytocin and vasopressin may play a role in the control of steroidogenesis.