Effects of intracerebroventricular administration of calcitonin gene-related peptide (CGRP) on sex hormones and sperm quality in rats

Background: Therapeutic strategies with calcitonin gene-related peptide (CGRP) or its receptor have been investigated, but there are few studies regarding the possible harmful effects of CGRP in other body organs.Objective: This study aimed to investigate the effect of intracerebroventricular (ICV) injection of CGRP on sex hormones and sperm quality in rats.Methods: Twelve male rats were divided into two groups (n=6 per group). The first group (control) rats were injected with 5 mu l artificial cerebrospinal fluid intra-ICV; the second group rats, 5 mu l (1.5 nmol) CGRP. The levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were measured. Epididymal sperms were used to determine the sperm parameters.Results: The levels of testosterone, LH and FSH in CGRP group was significantly lower than in artificial cerebrospinal fluid (ACSF) group (P<0.05). The concentration and motility of sperm in CGRP group was significantly lower than in ACSF group (P<0.05). In CGRP group live spermatozoa and intact acrosome significantly reduced compared to the ACSF group (P<0.05). In addition, in CGRP group dead spermatozoa and lose acrosome significantly increased compared to the ACSF group (P<0.05).Conclusion: ICV injection of CGRP may reduce sperm quality, probably through induction of an imbalance in FSH and LH production as well as testosterone.