RESERPINE AND THE CHRONIC STRESS OF REDUCED BAROMETRIC PRESSURE IN FEMALE RATS. OBSERVATIONS ON BODY WEIGHT, ADRENAL WEIGHT AND HISTOLOGY AND HEMATOCRIT VALUES1

Abstract

Sprague-Dawley rats were given reserpine in two dose patterns at ground level and at several patterns of low barometric pressure exposure. The latter was at 18,000 and 27,000 feet altitude equivalent levels. Observations were made on body weight, adrenal weight, histology and hematocrit levels. Rats receiving reserpine lost weight, both at ground level and at altitude. Rats at ground level given an initial heavy dose of reserpine lost much weight but regained weight subsequently even though they were injected daily with small doses. Rats on small doses throughout lost weight at altitude, but placebo-injected and reserpine-injected rats lost weight as well. Adrenal glands decreased slightly in absolute weight in placebo treated animals at altitude. Rats receiving an initial heavy dose of reserpine showed an increase in absolute adrenal weight, and an increase relative to body weight. The small dose of reserpine yielded a decrease in absolute weight but a smaller loss of weight relative to the terminal body weight. There was loss of fat in the adrenal gland with reserpine, especially at altitude, and vascular engorgement was seen at the higher altitudes when reserpine was given. Hematocrit levels increased in all animals at altitude, but more so in rats receiving reserpine. Reserpine, in the dosage and patterns administered, did not prevent or reduce acclimatization changes as judged by loss of body weight, change in adrenal size, adrenal histology or blood hematocrit levels. On the contrary, the drug served as an added stress upon the organism in these respects.