[Influence of neonatal hypothyroidism on the response of the adrenal medulla of young rats to a physiological stimulation]

Abstract

The adrenal medulla of control and hypothyroid young rats was stimulated through insulin hypoglycaemia. In the control animals, the intensity of the depletion of the adrenal epinephrine, which occurs in response to hypoglycaemia, increases up to 10 days of age. Neonatal hypothyroidism results in a retarded evolution. Following epinephrine depletion, the activities of adrenal tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) are transitorily increased in the 14 day-old controls; these increases are the consequence of transsynaptic inductions. Hypothyroidism decreases TH induction and completely suppresses that of DBH.