[Seasonal dynamics of adrenal mineralocorticoid function in rats].

Seasonal peculiarities of adrenal mineralocorticoid function and some aspects of its regulation have been studied in experiments on male Wistar rats. It has been found that changes in aldosteronemia and aldosteronurea were maximum in spring and minimum in summer--autumn period. The highest indices of aldosterone metabolic clearance from plasma were observed in winter with the following progressing decrease and a small increase in autumn. The diagram of melatonin content in the epiphysis of experimental rats was the same. Hypokinesia attenuated aldosteronurea during all the investigation periods, preserving the character of aldosterone secretion year curve. PRA level changed irrespective of aldosterone levels in plasma and urea. It has been concluded that a certain stability of mineralocorticoid adrenal function seasonal rhythms has different regulating effects.