Evidence that calcitonin plays a role in the postnatal increase of serum 1 alpha,25-dihydroxyvitamin D.
To investigate the changes in the 1 alpha,25-dihydroxyvitamin D [1,25(OH)2D] level and the role of parathyroid hormone (PTH) and calcitonin (CT) during the early neonatal periods, we measured 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, mean +/- 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 less than 0.01 and r = 0.341, n = 50, P less than 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 less than 0.05, n = 24) as well as the relative increase of 1,25(OH)2D (delta pg/ml) after birth vs CT at age 5 days (r = 0.537, P less than 0.01, n = 24).(ABSTRACT TRUNCATED AT 250 WORDS)
Nishioka
T
T
Department of Paediatrics, Chiba University, School of Medicine, Japan.
Yasuda
T
T
Niimi
H
H
Nakajima
H
H
D002112:Calcifediol / Q000097:blood; D002116:Calcitonin / Q000502:physiology*; D002117:Calcitriol / Q000097:blood*; D003404:Creatinine / Q000652:urine; D000242:Cyclic AMP / Q000652:urine; D005260:Female; D005312:Fetal Blood / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn / Q000097:blood / Q000502:physiology*; D010281:Parathyroid Hormone / Q000502:physiology; D011247:Pregnancy
D010281:Parathyroid Hormone; D002116:Calcitonin; D003404:Creatinine; D000242:Cyclic AMP; D002117:Calcitriol; D002112:Calcifediol