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 pe ptide 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 bet ween flashes and 4 were obtained during each flash. The samples were analyz ed for calcitonin gene-related peptide and neuropeptide Y using radioimmuno assay technique. Hot flashes were objectively recorded by measuring periphe ral skin temperature and skin conductance. Results: Plasma calcitonin gene-related peptide increased 46% (95% confiden ce 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 tempe rature 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. T hus, there may be a similar mechanism of hot flashes in women and in men de prived of sex steroids.