The Journal of Clinical Endocrinology 6 Metabolism

I I N F A N T boys, a transient increase of gonadotropins, especially L H , occurs during the first months of life (1). A striking elevation of plasma androgens is associated wi th this increase (2). I n the same age group we also found enhanced testicular activity (3). Testicular testosterone concentrations were maximal in boys 1-3 months of age, wi th peak values similar to those in pubertal or even adult testes. Thereafter, testicular testosterone declined sharply and reached the low normal range for older prepubertal boys by 6 months of age. Plasma and testicular testosterone concentrations were closely correlated, which indicates the testes are the source of the early plasma testosterone surge. I n contrast, testicular androstenedione concentrations were low, and there was no correlation between plasma and testicular androstenedione concentrations. These results suggested that the infantile testes contribute l i t t le to circulating androstenedione concentrations. To evaluate the significance of the adrenal cortex as a source of circulating androgens in male infancy, we measReceived May 21, 1985. Address correspondence and requests for reprints to: Dr. F. Bidlingmaier, Children's Hospital, University of Munich, Lindwurmstrasse 4, D-8000 Munich 2, West Germany. * This work was supported by Grant Bi 306/1 from the Deutsche Forschungsgemeinschaft. ured androstenedione and testosterone in whole adrenals of previously healthy infant boys who died suddenly. Many of the subjects were identical to those from whom testes were taken for a previous investigation of testicular androgens (3). Thus, we compared the androgen content of adrenals and testes and estimated the relative contribution of both glands to the circulating levels of androstenedione and testosterone during infancy. Subjects and Methods