CHANGES IN PLASMA LUTEINIZING-HORMONE, TESTOSTERONE AND ESTRADIOL-17-BETA LEVELS AND SEMEN QUALITY AFTER INJECTIONS OF GONADOTROPIN-RELEASING-HORMONE AGONIST AND HUMAN CHORIONIC-GONADOTROPIN IN 3 DOGS WITH OLIGOZOOSPERMIA AND 2 DOGS WITH AZOOSPERMIA

Plasma luteinizing hormone (LH) and testosterone (T) levels in three n ormal male Beagles increased markedly, the LH levels peaking at 30 or 45 min and the T levels at 45 or 60 min respectively, after a subcutan eous injection of 1 mu g kg(-1) gonadotropin releasing hormone agonist (GnRH-A). Two Collies and a Great dane diagnosed as oligozoospermic a nd two Shetland sheep dogs diagnosed as azoospermic by evaluation of s emen quality were treated with 1 mu g kg(-1) GnRH-A after blood collec tion. Their plasma levels of LH, T and estradiol-17 beta (E-2) were me asured by radioimmunoassay for the purpose of investigating the effect of hormone therapy on spermatogenic dysfunction and the mechanism on improvement of semen quality. The semen quality of one of the Collies had improved 4 weeks after the GnRH-A treatment. The dog was treated w ith GnRH-A again and mated with a bitch 4 days later. The bitch gave b irth to five puppies. The other dogs, whose semen quality had not impr oved, were treated with an intramuscular injection of 500 or 1000 IU h uman chorionic gonadotrphin (hCG) per animal. Since the semen quality of the other Collie and the Great Dane improved temporarily 2 and 4 we eks, respectively, after hCG treatment, the former was mated with a bi tch 5 days later. The bitch gave birth to a litter of seven puppies. T hese hormone treatments, however, had no effect on the azoospermia in the two Shetland sheep dogs. Although the mean plasma LH and T levels in the dogs with oligozoospermia had been low, their LH levels gradual ly increased after hormone treatment. There were no marked changes in plasma T or E-2 levels. These findings indicate that the semen quality of dogs with oligozoospermia can be temporarily improved between 2 an d 4 weeks after a single injection of GnRH-A or hCG and the fertility of the dogs restored by the injection. (C) 1997 Elsevier Science B.V.