THE ROLE OF THE GENITOFEMORAL NERVE AND CALCITONIN-GENE-RELATED PEPTIDE IN CONGENITALLY CRYPTORCHID MUTANT TS RATS

We investigated whether previous gubernacular denervation in TS rats c hanges the gubernacular contractile response to or binding capacity of calcitonin gene-related peptide receptors. In TS rats there is excess ive calcitonin gene-related peptide in the genitofemoral nerve and 85% of the male rats have cryptorchidism. TS rats and controls underwent genitofemoral nerve transection or sham operation at day 0. On day 3 g ubernacula were cultured with or without calcitonin gene-elated peptid e to observe contractions. Gubernacular frozen sections were incubated with (125)iodine calcitonin gene-related peptide with or without unla beled calcitonin gene-related peptide. Exposed x-ray films were quanti fied by computerized densitometry. In the sham operated controls contr actility increased from 15 to 55% by adding calcitonin gene-related pe ptide compared with 5% and 10%, respectively, in the TS rats. After ge nitofemoral nerve denervation exogenous calcitonin gene-related peptid e increased contractility to 90% in controls and 75% in TS rats. Previ ous genitofemoral nerve transection increased specific (125)iodine cal citonin gene-related peptide binding 21% in controls and about 100% in TS rats. Genitofemoral nerve transection in TS rats restored gubernac ular contractile response to calcitonin gene-related peptide in vitro and doubled the binding capacity of calcitonin gene-related peptide re ceptors.