Protection of adrenocortical activity by dietary casein in rats treated with estrogen

We have studied the effects of casein-enriched diet on adrenal weights and Delta(5)-3 beta-hydroxysteroid dehydrogenase (Delta(5)-3 beta-HSD) activity , and serum corticosterone levels, in estrogen-treated rats. Adult male rat s on a 5% or 20% casein diet received injections of oestriadiol-17 beta (50 mu g/100 g b.wt./day) for 7 days. Adrenal weight, adrenal Delta(5)-3 beta- HSD activity and serum corticosterone levels were significantly higher in r ats fed the 5% casein diet and killed 7 days after the last injection of es trogen as compared to their controls. All the parameters were similar to co ntrol levels in rats receiving the 20% casein diet and treated with estroge n. The total protein content of both the diets (5% and 20% casein) was equa l. These results suggest that casein may play a role in protecting adrenoco rtical function in the presence of exogenous oestradiol-17 beta. Med Sci Re s 27:415-417 (C) 1999 Lippincott Williams & Wilkins.