THE EFFECTS OF SEVERAL VARIETIES OF STRESS ON THE CHOLESTEROL CONTENT OF THE ADRENAL GLANDS AND OF THE SERUM OF RATS1

Abstract

The adrenal cholesterol of adult d1 rats fell to half the normal level as a result of exposure to barometric pressures of 200-300 mm. Hg for periods of 1-7 hrs. Animals dying during exposure, some after only 15 mins., suffered a similar adrenal cholesterol loss. Those animals allowed to recuperate for 18 hrs. at normal atmospheric pressure showed complete restoration of the adrenal cholesterol stores. Exposure to low pressure had no effect on the serum cholesterol conc. Rats subjected to temps. of 0-5[degree] C. for 16-22 hrs. suffered a small loss of adrenal cholesterol but in those exposed to cold for 72 hrs. the cholesterol content of the adrenals was normal. Apparently exposure to cold causes an early depletion followed by later restoration of the adrenal cholesterol. Complete starvation for 72 hrs. did not alter the cholesterol content of the adrenals although it did produce a slight but significant hypocholesteremia. Prolonged treatment of unilaterally nephrectomized rats with large doses of desoxycorticosterone acetate caused irregular increases in the adrenal cholesterol content. The serum cholesterol conc, however, was quite uniformly elevated. Diethylstilbestrol adm. induced a rapid and progressive loss of cholesterol from the adrenal glands and from the serum. The resultant very low cholesterol levels were maintained for the duration of the longest expt. (34 days) without any indication of restorative changes. It is thought that stilbestrol produces this effect by stimulating the ant. hypophysis to secrete excessive amts. of adrenotrophic hormone and this substance, by causing adrenal hyperactivity, depletes the adrenal cholesterol content.