[Catecholamine sensitivity of the hypophyseal-adrenal system in the early ontogeny of rats].

The dynamics of the hypophyseal-suprarenal system reaction to catecholamines of different type of effect was studied in the Wistar rats during the first 16 days of life. The reaction to epinephrine was noted in 4 days old and to novodrin in 8 days old rats. Since the reaction to epinephrine acting on alpha- and beta-receptors appears ahead of that to novodrin acting selectively on beta-receptors, a suggestion was put forward to the effect that alpha-receptors matured more rapidly that beta-receptors. The increase of the system reaction to the stimulation of recepors sensitive to catecholamines was noted on the 12-14th days of life and appears to be related to the formation of central adrenergic mechanisms.