Springer Online Journal Archives 1860-2000
Abstract To investigate the changes in the 1α, 25-dihydroxyvitamin D [1,25(OH)2D] level and the role of parathyroid hormone (PTH) and calcitonin (CT) during the early neonatal periods, we measure 1,25(OH)2D, 25-hydroxyvitamin D [25(OH)D], PTH specific for mid-regions (mPTH) and urinary cAMP (UcAMP) to evaluate the renal tubular responsiveness to intrinsic PTH and CT, as well as serum Ca and P in 28 mothers at term delivery and in their babies at birth and 5 days of age. Cord serum 1,25(OH)2D levels were low (28.8 ±9.2 pg/ml, means ±SD), while maternal serum 1,25(OH)2D levels were high (62.2±22.6 pg/ml). The low 1,25(OH)2D value increased 2.5 times (62.2±22.6 pg/ml) in 5-day-old infants, reaching a high normal adult value, concomitant with the increases in mPTH and urinary cAMP/creatinine ratio (UcAMP/Cr). The correlations between 1,25(OH)2D and UcAMP/Cr, and 1,25(OH)2D and mPTH in all paired samples of babies at birth and at 5 days of age were r=0.456, n=50, P〈0.01 and r=0.341, n=50, P〈0.05, respectively. These data suggest that the parathyroid activation after birth is a major factor in the rapid 1,25(OH)2D increment at that time. CT levels were high in all paired samples and in 5-day-old infants. CT vs 1,25(OH)2D showed a significant correlation (r=0.473, P〈0.05, n=24) as well as the relative increase of 1,25(OH)2D (Δpg/ml) after birth vs CT at age 5 days (r=0.537, P〈0.01, n=24). In the infants with low CT levels at 5 days the 1,25(OH)2D concentration failed to increase. These results suggest CT, in addition to PTH, may be important in the postnatal increase 1,25(OH)2 in term infants, though further direct evidence of the role of CT is necessary.
Type of Medium: