Osteocalcin Response to Calcium Load Test in Patients with Hypercalciuria

Abstract

Background.The present study demonstrates changes in the serum osteocalcin concentration after oral administration of calcium in patients with hypercalciuria, nephrolithiasis and primary hyperparathyroidism and the osteocalcin serum concentration as a differential diagnostic value for hypercalciurias. Eight of the control patients showed normal values of the serum osteocalcin during the control period with no calcium administration and the experimental period of OCTT, as follows: X1 = 3.05 ± 0.6 pmol/L and X2 = 3.65 ± l.1 pmol/L. The ninth patient from the control group showed an acute increase of the osteocalcin values-17.8 ± 3.8 respectively 23.9 ± 4.2 pmol/L during the experimental period of OCTT and he has been excluded from the study. The patients with absorptive hypercalciuria and recurrent calcium nephrolithiasis similar to the controls showed an increase of the serum osteocalcin during the experimental period of OCCT from 2.11 ± 0.30 pmol/l to 3.36; ± 0.7 pmol/L, p>0.1, non-significant.Obviously serum osteocalcin level assessment does not contribute to the differential diagnosis in patients with hypercalciuria, but nevertheless it demonstrates the presence of the hormonal statement, involved in the regulation of Ca metabolism. An acute rise of serum osteocalcin levels was found after the oral calcium tolerance test in patients with renal hypercalciuria and osteoporosis.The administration of calcium activates the osteosynthesis processes and the release of high quantities of osteocalcin. The study of the serum osteocalcin gives more possibilities to estimate the status of the bone system when pathological changes such as hyperparathyroidism, renal hypercalciuria and osteoporosis occur.