Osteocalcin production in vivo and in vitro after 1,25-dihydroxycholecalciferol stimulation comparison of different assays
Villa, I.; Banfi, G.; Daverio, R.; Resmini, G.; Rubinacci, A.
European Journal of Clinical Chemistry and Clinical Biochemistry 34(9): 771-775
1996
ISSN/ISBN: 0939-4974 PMID: 8891532 Document Number: 465870
The study was designed to assess the sensitivity of three commercial assays (which differ in methodology, standard and antibodies) for osteocalcin, used for detecting changes in osteocalcin secretion induced by calcitriol (1,25-dihydroxycholecalciferol) in vivo and in vitro. Osteocalcin levels were determined in serum samples of 10 osteoporotic women after short term calcitriol treatment, and in the culture medium of human osteoblast-like cells (n = 22) after 48 h calcitriol exposure. All assays displayed similar sensitivity in detecting osteocalcin production in vivo after a 1 microgram daily dose of calcitriol. A novel IRMA (CIS), claimed to detect intact osteocalcin, showed higher osteocalcin values than the other assays, and in vitro showed the best sensitivity; it provides an appropriate index of the osteocalcin synthetic activity of cultured human osteoblasts.