Morphologic and endocrinologic characteristics of retained canine tests

The objective of this study was to assess macroscopic and microscopic chara cteristics of the testes in unilaterally cryptorchid dogs (n=16 and n=13, r espectively). An additional goal was to measure and compare plasma levels o f testosterone between the cryptoid (n=13) and control dogs (n=16). The siz e and weight of the retained tested were lower (P <0.01) compared with the descended testes in the unilaterally cryptoid dogs of different breeds, but there was no difference between the inguinal and abdominal cryptoid testes (P >0.01). Spermatogenesis was significantly suppressed in the cryptorchid testes compared with the contralateral testes of the unilaterally cryptorc hid dogs. The number of Leydig cells was higher (P <0.01) in the cryptorchi d than in scrotal testes. Plasma concentration of testosterone did not vary (P >0.1) between the cryptoid and control dogs. Normal endocrine function could be maintained in the cryptorchid dogs, despite the smaller testicular size of the retained testes.