Effects of endothelin-1 on the secretory capacity and proliferative activity of regenerating rat adrenal cortex

We investigated the effect of endothelin-l (ET-1) on the secretory capacity and proliferative activity of regenerating rat adrenals. Rats underwent left adrenal enucleation and contralateral adrenalectomy and were decapitated 4, 6 or 8 days after surgery. Animals were given two subcutaneous injection of 2 nmol kg(-1) ET-1, 24 and 12 h before decapitation, as well as 100 mg/100g vincristine 180 min before autopsy. At all the regeneration times tested, plasma aldosterone and corticosterone concentrations and adrenal mitotic index (% of metaphase-arrested cells) were significantly higher in ET-l-treated rats than in control animals. The conclusion is drawn that ET-1 stimulates the regeneration of enucleated adrenals in rats.