Intratesticular testosterone concentration in patients with disturbed fertility

45 patients with azoospermia or severe oligozoospermia were studied. Testosterone and luteinizing hormone in plasma were in the normal range. Intratesticular testosterone values were higher the greater the degree of tubular atrophy was. Patients with testes of subnormal size (less than 12 ml) had significantly higher values than those with normal sized gonads. 31 out of 37 testes obtained by castration of patients with carcinoma of the prostate showed slight to severe disturbance of spermatogenesis. In this group no positive correlation was observed between the degree of testicular atrophy and intratesticular testosterone concentrations. Intact spermatogenesis was observed in testes with a testosterone content as low as 542 pg/mg tissue.