Acute high altitude stress and enzyme activities in the rat adrenal medulla.

Abstract

Activities of specific adrenal enzymes participating in catecholamine synthesis in rats exposed to an altitude of 14,110 feet for 1, 3, 7 and 14 days were determined. Levels of tyrosine hydroxylase were significantly increased after 1, 3 and 7 days of exposure, but approached control levels after 14 days. Dopamine-β-hydroxylase levels were elevated even after 14 days of exposure. Phenylethanolamine-N-methyl transferase activities were increased after 3 and 7 days but not after 14 days of exposure. These findings indicate an increase in catecholamine turnover during the initial stages of high altitude exposure. (Endocrinology 91: 1447, 1972)