Abstract
Summary
Catecholamine content was increased in the urine of newborn swine exposed to 5° for six hours. Adrenal gland hormone levels were not changed under these conditions. Repeated handling (five days) depleted catecholamines and increased the in vitro activity of tyrosine hydroxylase in adrenal glands of neonatal piglets. Intermittent exposure to 5° for five days was no more effective than handling in inducing enzyme activity or depleting adrenal gland catecholamines. Tyrosine hydroxylase activity was enhanced in neonatal swine treated with 6-hydroxydopamine for two days. Adrenal catecholamine levels were lower in saline and 6-hydroxydopamine-treated animals than in unhandled controls. Phenethanolamine N-methyltransferase activity in the adrenal gland was not altered by handling, cold stress or 6-hydroxydopamine.
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