Abstract
SUMMARY In male mice of the C57BL/10J (C57) strain the testicular weight, sex drive and aggression are low compared with a number of other strains, indicating androgen deficiency. In contrast, DBA/2J (DBA) males were 'normal' in all studied parameters of testicular function. The weight of the seminal vesicles is similar in both strains. Plasma testosterone levels, and the responsiveness of the seminal vesicles to injected testosterone propionate in C57 and DBA animals were compared. Plasma testosterone levels were 1·3 ± 0·4 ng/ml in C57 and 4·6 ± 1·0 ng/ml in DBA mice. The increase in weight of the seminal vesicles after administration of testosterone propionate to castrated male mice was, however, considerably greater in C57 than in DBA mice. In order to restore the weight of the seminal vesicles to normal it was necessary to administer twice as much testosterone propionate to DBA than to C57 males.