title: Effect of the menstrual cycle on calcium-regulating hormones in the normal young woman.
abstract: To examine the effect of estrogens on circulating levels of calcium-regulating hormones, total serum calcium, ionized calcium, inorganic phosphate, immunoreactive parathyroid hormone, calcitonin, 1,25-dihydroxyvitamin D, and estradiol (E2) levels were assayed on menstrual cycle days 3 and 13 in 12 healthy young women. Despite a 3-fold increase in serum E2 levels by midcycle, no differences in the other factors were observed. Furthermore, iv infusion of calcium (3 mg/kg over a 10-min period) produced similar changes in the serum levels of immunoreactive parathyroid hormone and calcitonin on days 3 and 13 in 8 women. Our findings suggest that in normal menstruating women, endogenous increases in E2 neither directly nor indirectly stimulate 1,25-dihydroxyvitamin D production, nor do they affect circulating levels of the hormones known to influence calcium homeostasis in man.
mesh_terms: D000328:Adult; D002116:Calcitonin / Q000097:blood*; D002118:Calcium / Q000097:blood*; D004100:Dihydroxycholecalciferols / Q000097:blood; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D008598:Menstruation / Q000187:drug effects; D010281:Parathyroid Hormone / Q000097:blood*; D010758:Phosphorus / Q000097:blood
chemical_list: D004100:Dihydroxycholecalciferols; D010281:Parathyroid Hormone; D010758:Phosphorus; D004958:Estradiol; D002116:Calcitonin; D002118:Calcium