Biphasic effects of orchidectomy on calcitonin gene-related peptide synthesis and release

We hypothesize that the decline of male gonadal hormones may play a role in age-related decrease of calcitonin gene-related peptide (CGRP) synthesis a nd release. Orchidectomized rats were raised with or without testosterone r eplacement and CGRP levels in serum and some tissues as well as the perfusa te from the isolated mesenteric arterial bed (MAB) were measured at 1, 2 an d 4 months after orchidectomy. CGRP levels of serum and tissues, and CGRP r elease from MAB were significantly elevated after I month and decreased aft er 4 months in orchidectomized rats. The changes were restored by testoster one replacement. Our results indicate that the age-related decline of testo sterone might contribute to the age-related decrease of CGRP synthesis and release. (C) 2001 Lippincott Williams & Wilkins.