Contrasting effects of stress and cortisol overdosage in the rat

¹ Carter Physiology Laboratory, University of Texas Medical Branch, Galveston, Texas

Immature female albino rats were subjected to chronic stress and to cortisol overdosage singly and in combination. At a dosage of 1 mg/day the steroid produced slight augmentation of blood pressure, moderate inhibition of growth and great involution of the thymus. Stress, in the form of intermittently applied electrical shocks, although it had little effect on the thymus or on body growth, produced slight adrenal hypertrophy and a considerable hypertrophy of the preputial glands. Stress and cortisol together acted synergistically on body growth and thymus involution; but cortisol dominated the adrenal response and stress that of the preputial glands. There was only suggestive evidence that blood pressure effects of cortisol were augmented by stress. The possible usefulness of preputial hypertrophy in the assessment of chronic stress states is discussed.