[Testicular function in mice of inbred strains BALB/cLac, PT, and CBA/Lac]

The main features of male fertility: sperm production and abnormalities, testosterone serum concentration and its testicular content after hCG injections, weights of the testes and cauda epididymes, were studied in adult males of three inbred mice strains BALB/cLac, PT, and CBA/Lac. The CBA/Lac males were characterized by lower value of the epididymal sperm number, as well as lower weights of reproductive organs in comparison with males of other inbred strains. The lower number of sperm is accompanied in the CBA/Lac males with lower proportion of morphologically abnormal spermatozoa as compared to other strains that could compensate its decreased count and improve fertility. The baseline testosterone concentration and its testicular content did not differ among the three strains but the testosterone response to injection of 10 IU of hCG was weaker in the CBA/Lac males than in the others. The results indicate significant interstrain differences in testicular traits implicated in male fertility which may be correlated and compensate to each other.