['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.', '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.', '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.'] Is momentary increase in plasma calcitonin gene-related peptide involved in hot flashes in men treated with castration for carcinoma of the prostate?