[Changes in noradrenaline metabolism in the rat subjected to cold in the early postnatal period].

The adrenal gland norepinephrine content is elevated and 3H-norepinephrine lowered in adult rats exposed to cold during early postnatal period. 7-week test cooling of cold-imprinted animals induced a more obvious adrenal norepinephrine exchange than in control rats, phenylethanolamine-N-methyltransferase activity falling by a factor of two. The brown adipose tissue 3H-norepinephrine exchange was first intensified and then returned to normal level in control rats in cooling. The 3H-norepinephrine exchange was reduced in cold-imprinted animals after 7-week cooling.