CONGENITAL UNDESCENDED TESTES IN NEONATAL PIGS AND THE EFFECT OF EXOGENOUS CALCITONIN GENE-RELATED PEPTIDE

AbstractPurpose: We investigated the neonatal piglet as a possible animal model for cryptorchidism and to determine whether calcitonin gene-related peptide (CGRP), which has been proposed to regulate inguinoscrotal testicular descent, could induce testicular descent in piglets with congenital cryptorchidism.Materials and Methods: We examined 38 cryptorchid piglets to document the anatomy in 8 and to investigate the role of CGRP in 30. The 2-week-old piglets were allocated randomly to receive a mini-osmotic pump containing CGRP at various concentrations or phosphate buffered saline. The pump was inserted surgically into the ipsilateral scrotum, with the contents blinded to the surgeon. The positions of the testes, pump and anatomical landmarks were measured and photographed. The pigs were sacrificed and dissected 2 weeks later, and the positions were remeasured and photographed. The testes were examined histologically.Results: The 3 variants of cryptorchidism observed were intra-abdominal in 20 cases, ingu...