CHANGES IN PERIPHERAL PLASMA LUTEINIZING-HORMONE AND TESTOSTERONE CONCENTRATIONS AND SEMEN QUALITY IN NORMAL AND CRYPTORCHID DOGS DURING SEXUAL-MATURATION

Changes in peripheral plasma luteinizing hormone (LH) and testosterone (T) concentrations and semen quality were investigated in four unilat erally cryptorchid (UC), three bilaterally cryptorchid (BC), and five normal beagles, from 4 to 48 weeks of age, Blood samples were collecte d at 2- or 4-week intervals, and the LH and T concentrations were dete rmined by radioimmunoassay, Semen samples were collected weekly by dig ital manipulation, The mean LH and T concentrations in the normal dogs increased after 20 and 22 weeks of age and reached approximately 4 ng /ml and 3 ng/ml respectively at 36 weeks of age. Semen volume and tota l spermatozoa count increased apparently at 34 and 35 weeks of age res pectively, Spermatozoa motility and percentage of abnormal spermatozoa varied less after 38 weeks of age, Plasma LH and T concentrations in the UC and BC dogs had a tendency to remain lower than values in the n ormal dogs after 26 weeks of age. The semen volume and spermatozoa cou nt in the UC dogs did not increase markedly, The spermatozoa count was less than half that in normal dogs, and the percentage of abnormal sp ermatozoa was higher throughout the experimental period, Ah BC dogs ha d azoospermia. Thus it was evident that development of spermatogenic f unction during sexual maturation in the UC and BC dogs was insufficien t compared with that in normal dogs.