title: Fluctuation of serum concentration of 1,25-dihydroxyvitamin D3 during the menstrual cycle.
abstract: The serum concentrations of total calcium and 1,25-dihydroxyvitamin D3 were measured in seven women during a menstrual cycle. A rise in the serum level of 1,25-dihydroxyvitamin D3 was observed on day 15 of the cycle without a detectable change in the serum calcium level. The level of 1,25-dihydroxyvitamin D3 on day 15 was double the value at days 1 and 8 of the cycle. The peak of 1,25-dihydroxyvitamin D3 on day 15 was not observed in five women ingesting oral contraceptives, suggesting that ovulation or its hormonal control was involved in the peak on day 15. A small but significant fall in the serum calcium concentration occurred in the women ingesting oral contraceptives. In view of these findings the serum concentrations of 1,25-dihydroxyvitamin D in women with functioning ovaries must be interpreted in the context of the stage of the menstrual cycle when the blood sample was obtained.
mesh_terms: D000293:Adolescent; D000328:Adult; D002117:Calcitriol / Q000097:blood*; D002118:Calcium / Q000097:blood; D003276:Contraceptives, Oral / Q000494:pharmacology; D005260:Female; D006801:Humans; D008598:Menstruation; D010053:Ovary / Q000187:drug effects
chemical_list: D003276:Contraceptives, Oral; D002117:Calcitriol; D002118:Calcium