EFFECTS OF CAPTIVITY ON ADRENAL GLAND OF WILD NORWAY RAT

Abstract

This study is based on 89 wild Norway rats 19 of which were shot with a rifle, the adrenal glands of which were considered normal. The remainder were caught in box-type traps and not subjected to trauma, only the psychological effects of captivity. The wild Norway rat in the natural state has an adrenal gland about twice the size of the adrenal gland of a domestic rat of comparable body wt. The adrenal gland of the wild Norway rat has a cholesterol content of approx. 10%, about twice that of the domestic rat. Hence the wild rat has about 4 times as much adrenal cholesterol per unit of body wt. as does the domestic rat. Immediately after capture the gland of the wild rat undergoes hypertrophy with a loss of cholesterol. Within 24 hrs. the cholesterol content has returned to normal and the animal then has more adrenal cholesterol per unit of body wt. than when in the wild state. After 10 weeks of captivity the gland has returned to normal size.