The role of calcitonin gene-related peptide (CGRP) and cremaster muscle in the etiology of undescended testis

Abstract

Objective: Although different theories have been proposed about the descending mechanism of the testis and the causes of undescended testis (UDT), its etiopathogenesis hasn't been clearly explained. One of the most popular theories is the hypothesis that includes the genitofemoral nerve, CGRP and cremaster muscle (CM), which are mostly based on animal experiments. The adaptability of this hypothesis to human is controversial. In this study, we aimed to evaluate the possible role of CGRP in UDT by analyzing the CGRP receptor in the CM of children with and without UDT. Method: This clinical prospective study included 15 boys with UDT, 15 girls with inguinal hernia (IH) and 15 boys with IH. CM samples were taken during the operations. The CGRP receptors were demonstrated using the CGRP antibody. Results: No statistically significant difference was found between the groups in terms of age distribution. While CGRP receptor was detected in each boy group, it wasn't detected in the girl group. In the UDT group, there was a higher rate of receptors than the children with normal testis (64.7% and 35.3%, respectively), statistical difference between the groups was within the limit of significance (p=0.05). Conclusion: CGRP receptors in the CM weren't found in girls but only in boys, suggesting that CGRP may play a role in testicular descent. However, the fact that both the UDT and the descended testis group consisted of patients with and without receptors, restricted making a clear conclusion about this matter. We think that combined studies, including the effects of androgens and gubernaculum together with CM and CGRP are needed