PLASMA 1,25-DIHYDROXYVITAMIN D LEVELS IN PREGNANCY AND LACTATION

1979 ◽  
Vol 92 (2) ◽  
pp. 330-335 ◽  
Author(s):  
Bjarne Lund ◽  
Anders Selnes
Keyword(s):  
Calcium Absorption ◽  
Plasma Concentrations ◽  
Serum Prolactin ◽  
Serum Parathyroid Hormone ◽  
Human Pregnancy ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Causative Relationship ◽  
Pregnancy And Lactation ◽  
In Pregnancy

ABSTRACT Plasma concentrations of 1,25-dihydroxyvitamin D (1,25–(OH)2D), serum prolactin and serum parathyroid hormone (PTH) were followed during pregnancy and lactation in 16 women. High 1,25–(OH)2D was demonstrated in human pregnancy and lactation. A causative relationship between 1,25–(OH)2D and prolactin is discussed and a possible explanation of the mechanism of the augmented calcium absorption in human pregnancy and lactation is suggested.

SERUM FREE 1,25-DIHYDROXYVITAMIN D AND THE FREE 1,25-DIHYDROXYVITAMIN D INDEX DURING A LONGITUDINAL STUDY OF HUMAN PREGNANCY AND LACTATION

1990 ◽  
Vol 32 (5) ◽  
pp. 613-622 ◽  
Author(s):  
SCOTT G. WILSON ◽  
ROBERT W. RETALLACK ◽  
JACQUELINE C. KENT ◽  
GRAEME K. WORTH ◽  
DONALD H. GUTTERIDGE
Keyword(s):  
Longitudinal Study ◽  
Serum Free ◽  
Human Pregnancy ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Pregnancy And Lactation

Calcium transport in small intestine during pregnancy and lactation

1980 ◽  
Vol 239 (1) ◽  
pp. E64-E68 ◽  
Author(s):  
B. P. Halloran ◽  
H. F. DeLuca
Keyword(s):  
Vitamin D ◽  
Reproductive Cycle ◽  
Calcium Transport ◽  
Plasma Concentrations ◽  
Dihydroxyvitamin D ◽  
Control Value ◽  
1,25 Dihydroxyvitamin D ◽  
Everted Gut Sac ◽  
Pregnancy And Lactation ◽  
Active Calcium

The factors involved in calcium homeostasis during the mammalian reproductive cycle and specifically in the control of active calcium transport in the intestine have not been thoroughly investigated. For this reason calcium transport in the intestine was measured in vitamin D-replete and vitamin D-deficient rats during pregnancy and lactation using the everted gut sac technique. In addition the changes in the plasma concentrations of calcium and 1,25-dihydroxyvitamin D were measured and correlated with transport. During the later stages of pregnancy and during lactation, the concentration of calcium in the plasma is reduced 10-30%. In turn, in the vitamin D-replete rat, the concentration of 1,25-dihydroxyvitamin D in the plasma increases from a control value of 26 pg/ml to 158 pg/ml at day 14 of lactation. Calcium transport in the intestine increases late in pregnancy, peaks during lactation, and then falls to control values by 3 wk postweaning in both vitamin D-replete and D-deficient animals. These findings strengthen the established relationship between 1,25-dihydroxyvitamin D and active calcium transport in the intestine as well as suggest that some factor(s) independent of vitamin D is stimulating intestinal calcium transport during the reproductive cycle.

Measurement of Plasma 1,25 Dihydroxyvitamin D Using a Novel Immunoextraction Technique and Immunoassay with Iodine Labelled Vitamin D Tracer

1997 ◽  
Vol 34 (6) ◽  
pp. 632-637 ◽  
Author(s):  
W D Fraser ◽  
B H Durham ◽  
J L Berry ◽  
E B Mawer
Keyword(s):  
Vitamin D ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Sample Volume ◽  
Cross Reactivity ◽  
Regression Equations ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
High Concentrations

We evaluated a novel assay for the measurement of 1,25 dihydroxyvitamin D (1,25 (OH)2D). Immunoextraction of 1,25 (OH)2D is performed using a mini column containing a solid-phase monoclonal antibody followed by radioimmunoassay (RIA) using an 125I-labelled 1,25 (OH)2D derivative tracer and Sac-cell separation. The mean recovery of 1,25(OH)2D3 was 101%, linearity was excellent, inter- and intra-assay coefficients of variation were 9, 8 and 13% and 11, 10 and 14% at low, medium and high concentrations of 1,25(OH)2D3, respectively. The cross-reactivity of vitamin D metabolites was <0·0015% for 25-hydroxyvitamin D3, 24, 25 dihydroxyvitamin D3 and dihydrotachysterol and 0·54% for lα calcidol. 1,25 dihydroxyvitamin D2 cross-reactivity was 79%. The detection limit of the assay was 5pmol/L. Comparison with a commercial radio receptor assay (RRA) and an in-house RIA gave regression equations of y = 0·94x+11·8 ( r = 0·98) and y = 0·91x-1·7 ( r = 0.95), respectively, with no major discrepancies between the methods in all patient groups studied. Plasma concentrations of 1,25 (OH)2D obtained with the assay were as follows: normal, unsupplemented subjects: mean 88, range 48–155 pmol/L, n = 68, patients with chronic renal failure: mean 11, range 3–36 pmol/L, n = 27, primary hyperparathyroidism: mean 198, range 130–299 pmol/L, n = 23, Paget's disease: mean 92, range 42–149 pmol/L, n = 24, osteomalacia: mean 43, range 27–61 pmol/L, n = 9. A minimum sample volume of 300 μL is required, the hands-on time is significantly less than other commercial assays and the measuring procedure is gamma counting rather than scintillation counting. The assay offers several advantages over previous methods and should allow more laboratories to offer measurement of 1,25 (OH)2D as part of their repertoire.

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