[Seasonal differences in the sensitivity of the catecholamine receptors of the brain in connection with the endocrine function of the pituitary-testicular complex].

The fluorimetric method was applied to the study of testosterone level in the peripheral blood plasma after the administration of substances stimulating catecholamine receptors of sexually mature Wistar male rats at different seasons of the year. Dophamine administration (a dose of 10 microgram) caused an increase in the blood testosterone level (twice) both in summer and in winter. At the same time noradrenaline stimulating chiefly the alpha-adrenoceptors and isopropylnoradrenaline (novodrin) acting chiefly on beta-adrenoceptors produced a stimulating action in the same doses in summer only. In winter the activation of the hypothalamo hypophysio-testicular complex was noted after the administration of these substances into the lateral ventricle in a dose of 100 microgram only. A conclusion was drawn that, in difference from dophamine receptors, sensitivity of alpha- and beta-adrenoceptors connected with the endocrine function of the hypothalamo-hypophysio-testicular complex depended on the seasonal factors. It is supposed that the brain adrenoceptors were capable of participating in the regulation of seasonal dynamics of testosterone content in the blood.