ACTH increases adrenal medullary PNMT activity in neonatal rats.
Levels of plasma corticosterone and the activities of adrenomedullary dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyltransferase (PNMT) were measured in the 7-day-old rat following the administration of adrenocorticotropic hormone (ACTH) for 7 consecutive days beginning with day 1. ACTH led to significant adrenal hypertrophy and a concomitant elevation (10 to 15 fold) of plasma corticosterone concentration. Whereas DBH activity remained unchanged, adrenal PNMT activity was increased significantly following ACTH-induced elevation of plasma corticosterone levels. These results indicate that the pituitary-adreno-cortical-adrenomedullary axis is functional in the neonatal rat. Furthermore, since the transsynaptic control mechanisms are known to be non-functional or immature in the 7-day-old rat, our data suggest that neonatal rat adrenal catecholamine biosynthesis may be largely controlled by the pituitary-adrenocortical axis via glucocorticoids.
D000311:Adrenal Glands / Q000033:anatomy & histology; D000313:Adrenal Medulla / Q000187:drug effects / Q000201:enzymology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D000324:Adrenocorticotropic Hormone; D004299:Dopamine beta-Hydroxylase; D010625:Phenylethanolamine N-Methyltransferase; D003345:Corticosterone