Momentary Increase in Plasma Calcitonin Gene-Related Peptide Is Involved in Hot Flashes in Men Treated With Castration for Carcinoma of the Prostate

PURPOSE: In women the vasodilatory neuropeptides calcitonin gene-related peptide and neuropeptide Y seem to be involved in menopausal hot flashes. We assessed whether plasma calcitonin gene-related peptide and neuropeptide Y change during hot flashes in men after castration. MATERIALS AND METHODS: We evaluated 10 men 61 to 81 years old who underwent castration due to cancer of the prostate and had frequent hot flashes for changes in plasma calcitonin gene-related peptide and neuropeptide Y during 1 day at the outpatient clinic. At least 5 blood samples were obtained between flashes and 4 were obtained during each flash. The samples were analyzed for calcitonin gene-related peptide and neuropeptide Y using radioimmunoassay technique. Hot flashes were objectively recorded by measuring peripheral skin temperature and skin conductance. RESULTS: Plasma calcitonin gene-related peptide increased 46% (95% confidence interval 21 to 71) during flashes in the 6 men in whom it was measurable. This change was statistically significant (p = 0.028). The concentration of neuropeptide Y was below the detection limit. Skin conductance and temperature increased significantly during flashes. CONCLUSIONS: Calcitonin gene-related peptide is involved in the mechanisms of hot flashes in men who underwent castration due to prostate carcinoma. Thus, there may be a similar mechanism of hot flashes in women and in men deprived of sex steroids.