Testosterone: effect on rat testis

Testosterone (T) in low doses exerts its effects on the testis by suppressing serum luteinizing hormone (LH) and subsequent Leydig cell secretion of T, thereby producing a decrease in the high intratesticular concentrations of T which are necessary for maintenance of the germinal epithelium. High dose T, although suppressing both LH and follicle stimulating hormone (FSH), provides circulating levels of T sufficiently high (producing a threefold increase in ventral prostate weight) to maintain the germinal epithelium.