Vitamin D Homeostasis in the Perinatal Period

Steichen, Jean J.; Tsang, Reginald C.; Gratton, Tari L.; Hamstra, Alan J.; DeLuca, Hector F.

doi:10.1056/nejm198002073020603

Cited by 173 publications

(31 citation statements)

References 24 publications

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“…The concentration of 1,25-(OH)2D3 increases during pregnancy (Fig. 3), confirming previous data (4)(5)(6)(7)(8) month of pregnancy, however, a real increase in free 1,25-(OH)2D3 occurs, and this coincides with the period of large calcium transfer from the mother to the fetus (41). Other data also favor this hypothesis, as the decrease in serum ionized calcium (42) and the increase in serum parathyroid hormone (43,44) is also limited to the last period of pregnancy.…”

Section: Resultssupporting

confidence: 91%

“…The concentration oftotal 1,25(OH)2D3 in cord serum is lower than in maternal serum, as has also been observed by Steichen et al (7). At 35 wk of gestation, the total and free 1,25(OH)2D3 concentrations in cord serum are not different from nonpregnant values.…”

Section: Resultssupporting

confidence: 80%

“…It was previously shown that there is no correlation between the serum concentration of 25-hydroxyvitamin D3 and DBP, indicating that the level of free 25-OHD3 is not feedback regulated (3). The serum concentration of la,25-dihydroxyvitamin D3 (1,25-[OHh2D3) increases during human pregnancy (4)(5)(6)(7)(8), and this has been interpreted as a physiological adaptation to increase the intestinal calcium absorption in compensation for or even anticipation of the transfer of calcium to the fetus (8). The serum concentration of DBP, however, also increases during pregnancy or during the intake of estro-progestogens (3,9), and the relative increase in both concentrations has not been compared.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Vitamin D-binding Protein on the Serum Concentration of 1,25-Dihydroxyvitamin D3

Bouillon¹,

Assche²,

Baelen³

et al. 1981

J. Clin. Invest.

501

260

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A B S T R A C T The influence of the serum binding protein (DBP) for vitamin D and its metabolites on the concentration of its main ligands, 25-hydroxyvitamin D3 (25-OHD3) and 1,25-dihydroxyvitamin D3 (1,25-[OHh2D3) was studied. The concentration of both 1,25-(OH)2D3 and DBP in normal female subjects (45±14 ng/liter and 333±58 mg/liter, mean+SD, respectively; n = 58) increased during the intake of estro-progestogens (69±27 ng/liter and 488±90 mg/liter, respectively; n = 29), whereas the 25-OHD3 concentration remained unchanged. A positive correlation was found between the concentrations of 1,25-(OH)2D3 and DBP in these women.At the end of pregnancy, the total concentrations of 1,25-(OH)2D3 (97±26 ng/liter, n = 40) and DBP (616 ±84 mg/liter) are both significantly higher than in nonpregnant females and paired cord serum samples (48±11 ng/liter and 266±41 mg/liter, respectively). A marked seasonal variation of 25-OHD3 was observed in pregnant females and their infants, whereas in the same samples the concentrations of both DBP and 1,25-(OH)2D3 remained constant throughout the year.The free 1,25-(OH)2D3 index, calculated as the molar ratio ofthis steroid and DBP, remains normal in women taking estro-progestogens, however, and this might explain their normal intestinal calcium absorption despite a high total 1,25-(OH)2D3 concentration. In pregnancy the free 1,25-(OH)2D3 index remains normal up to 35 wk of gestation, but during the last weeks of Part of this work was presented at

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of the Vitamin D-binding Protein on the Serum Concentration of 1,25-Dihydroxyvitamin D3

Bouillon¹,

Assche²,

Baelen³

et al. 1981

J. Clin. Invest.

501

260

View full text Add to dashboard Cite

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“…The stimulus for the increase in calcitriol during pregnancy remains unknown, however. It seems to be unrelated to serum PTH, as the concentrations of intact-PTH were found to decrease with advancing gestation in our pregnant women, which is consistent with several earlier findings (16,(23)(24)(25)(26). In addition, an increase in intact-PTH concentrations postpartum paralleled a decrease in the concentrations of calcitriol (Figs 1 and 2), thus the increase in PTH postpartum did not result in further synthesis of calcitriol -an expected stimulus for enhanced calcium absorption.…”

Section: European Journal Of Endocrinology (1997) 137supporting

confidence: 91%

Calcium-regulating hormones and parathyroid hormone-related peptide in normal human pregnancy and postpartum: a longitudinal study

Ardawi

Nasrat²,

Ba'Aqueel³

1997

European Journal of Endocrinology

180

129

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Objectives: To evaluate calcium-regulating hormones and parathyroid hormone-related peptide (PTHrP) in normal human pregnancy and postpartum in women not deficient in vitamin D. Design: A prospective longitudinal study was conducted in pregnant Saudi women during the course of pregnancy (n ¼ 40), at term and 6 weeks postpartum (n ¼ 18). Maternal concentrations of serum calcidiol and calcitriol were determined, together with those of serum intact-parathyroid hormone (PTH), PTHrP, calcitonin, osteocalcin, human placental lactogen (hPL), prolactin, vitamin D binding protein, alkaline phosphatase, calcium, phosphate and magnesium. A group of non-pregnant women (n ¼ 280) were included for comparative purposes. Results: The calcidiol concentrations decreased (meanϮS.D.) significantly from 54Ϯ10 nmol/l in the first trimester to 33Ϯ8 nmol/l in the third trimester (P < 0:001) and remained decreased at term and postpartum (both P < 0:001). The calcitriol concentration increased through pregnancy, from 69Ϯ17 pmol/l in the first trimester to 333Ϯ83 pmol/l at term (P < 0:001). Intact-PTH concentrations increased from 1.31Ϯ0.25 pmol/l in the first trimester to 2.26Ϯ0.39 pmol/l in the second trimester, but then declined to values of the first trimester and increased significantly postpartum (4.02Ϯ0.36 pmol/l) (P < 0:001). PTHrP concentration increased through pregnancy from 0.81Ϯ0.12 pmol/l in the first trimester to 2.01Ϯ0.22 pmol/l at term and continued its increase postpartum (2.63Ϯ0.15 pmol/l) (P < 0:001). Significant positive correlations were evident between PTHrP and alkaline phosphatase up to term (r ¼ 0:051, P < 0:001) and between PTHrP and calcitriol (r ¼ 0:46, P < 0:001), osteocalcin (r ¼ 0:23, P < 0:05) and prolactin (r ¼ 0:41, P < 0:05) during pregnancy. Osteocalcin started to increase from 0.13Ϯ0.01 nmol/l in the second trimester, through pregnancy and postpartum (P < 0:001). Calcitonin was increased more than twofold by the second trimester compared with the first trimester (P < 0:001) and subsequently decreased (P < 0:001). Prolactin concentrations were significantly greater in the second (6724Ϯ1459 pmol/l) and third (8394Ϯ2086 pmol/l) trimesters compared with values before pregnancy (P < 0:001). hPL increased throughout the course of pregnancy, reaching a maximum at term (7.61Ϯ2.57 mIU/ml). There was no direct correlation between serum calcitriol concentrations during pregnancy and serum prolactin (r ¼ ¹0:12, P < 0:19) or serum hPL (r ¼ 0:17, P < 0:21). Significant changes were observed in the serum concentrations of calcium and phosphate, but not in that of magnesium, during the course of pregnancy; calcium concentrations showed a maximal decrease at term. Conclusions: Changes in serum PTHrP during the course of pregnancy, at term and postpartum have been demonstrated, suggesting that the placenta (during pregnancy) and mammary glands (postpartum) are the main sources of PTHrP. No support for the concept of 'physiological hyperparathyroidism' of pregnancy could be demonstrated in the present work. The ...

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“…In agreement with this view, we and others have demonstrated a significant increase in 1,25-(OH)2D levels within 1-3 d of birth in term (21) and preterm (15) infants. In newborn rat pups, however, no 1,25-(0H)zD appears to be produced in the first week of life, even in response to hypocalcemia (25).…”

Section: Discussionsupporting

confidence: 91%

Effect of Exchange Transfusions with Citrated Blood on Plasma Concentrations of Vitamin D Metabolites in Neonates

et al. 1984

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The plasma concentrations of total and ionized Ca are high in cord blood, but decrease within 1-2 d ofbirth in healthy neonates (4, 1 1, 20). The subsequent stabilization of Ca levels depends on a number of endocrine and non-endocrine factors, such as Ca and phosphate intakes, serum magnesium levels, and PTH and calcitonin secretions (4, 7, 1 1, 16, 18).The vitamin D endocrine system is of prime importance for Ca homeostasis because it stimulates intestinal absorption and skeletal mobilisation of the ion (5). Its significance for immediate postnatal mineral metabolism, however, has not been defined (22).In order to evaluate newborn infants' ability to produce 1,25-(OH)?D, which is the hormonal form of vitamin D, we studied the effect of exchange transfusions with citrated blood on the plasma concentrations of vitamin D metabolites. MATERIALS AND METHODSTen exchange blood transfusions were done for hyperbilirubinemia in seven newborn babies. Six of the infants had blood group incompatibilities, whereas one had jaundice of unknown etiology. Two were born prematurely (gestational ages, 30 and 35 wk, birth weights, 1300 and 1750 g), the remainder were delivered at term and had appropriate birth weights (3000-4360 g). The pregnancies and deliveries had been uneventful. All had 1-and 5-min Apgar scores of eight or above, and none had neonatal disease other than the hyperbilirubinemia.The exchange transfusions were performed at the median age of 38 h (range, 6-84 h), and lasted for 1-1 '/2 h. The median volume of blood exchanged was 110 ml/kg body weight (range, 90-185 ml/kg). No Ca was given during the procedure. CPD in a volume of 12 ml per 100 ml of blood, was used as anticoagulant and preservative for donors' blood.Plasma was collected from the first and last aliquots aspirated from the babies and from the donors' blood. The concentrations of 25-OHD, 1,25-(OH)zD, and 24,25-(0H)zD were determined from 1.5 ml of serum according to previously described methods (1, 2). All samples from one patient were analyzed in the same assay to minimize the effect of interassay variability. The intraand interassay coefficients of variation have been found to be 6.3 and 8.5%, respectively, for 25-OHD; 9.7 and 12.1% for 1,25-(OH)?D; and 7.0 and 9.7% for 24,25-(OH)?D.Concentrations of vitamin D binding protein (gc globulin or DBP) were assessed by quantitative immunoelectrophoresis (1 3) using rabbit immunoglobulin to human gc globulin (DAKO immunoglobulins A/S, Denmark). Bilirubin and phosphate concentrations were determined by standard laboratory methods.The data were expressed as medians with ranges. Differences were tested for statistical significance using the Wilcoxon test for paired data. Associations were calculated by linear regression analysis and expressed in terms of the correlation coefficient. RESULTSFor 25-OHD and 24,25-(OH),D, the postexchange concentrations were intermediate between the pre-exchange and donors' values, as were the bilirubin levels (Fig. I). The postexchange values correlated with both the pre-exchange...

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Vitamin D Homeostasis in the Perinatal Period

Cited by 173 publications

References 24 publications

Influence of the Vitamin D-binding Protein on the Serum Concentration of 1,25-Dihydroxyvitamin D3

Influence of the Vitamin D-binding Protein on the Serum Concentration of 1,25-Dihydroxyvitamin D3

Calcium-regulating hormones and parathyroid hormone-related peptide in normal human pregnancy and postpartum: a longitudinal study

Effect of Exchange Transfusions with Citrated Blood on Plasma Concentrations of Vitamin D Metabolites in Neonates

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