Synthesis of 1,25-Dihydroxyvitamin D in the Nephrectomized Pregnant Rat*

Weisman, Yosef; Vargas, Alfonso; Duckett, Gregory E.; Reiter, Edward O.; Root, Allen W.

doi:10.1210/endo-103-6-1992

Cited by 101 publications

(48 citation statements)

References 11 publications

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“…The basic experiment of Fraser and Kodicek was responsible for the concept that the kidney is the sole site of production of 1,25-(OH)2D3, and, in fact, this remains true for all animals except pregnant females. Weisman et al (6) reported that anephric, pregnant female rats could biosynthesize a compound that appeared to be 1,25-(OH)2D3. Similar experiments by Gray et al (7) provided even stronger evidence that pregnant, anephric female rats were capable of producing 1,25-(OH)2D3.…”

mentioning

confidence: 99%

See 1 more Smart Citation

In vitro production of 1,25-dihydroxyvitamin D3 by rat placental tissue.

Tanaka¹,

Halloran²,

Schnoes³

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

131

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Weanling female rats were fed a vitamin Ddeficient diet for 4 months until they reached maturity. They were mated with normal, vitamin D-replete male rats and, at 20 days of pregnancy, the female rats were killed and their placentae were removed, homogenized, and incubated with 25-hydroxyvitamin D3. The incubation mixtures were extracted and the extracts were subjected to Sephadex LH-20 column chromatography followed by high-pressure liquid chromatography. The 1,25-dihydroxyvitamin D3 region of the high-pressure liquid chromatogram was recycled to purity and the structure of the product was identified as 1,25-dihydroxyvitamin D3 by ultraviolet absorption spectrophotometry and by mass spectrometry. Thus Preparation of Placental Tissue. On the 20th day of pregnancy, mothers were anesthetized with ether. An abdominal incision was made and the animals were bled from the dorsal aorta. The uterus was then removed and the placenta was separated from the fetus. Placentae were placed in ice-cold 0.25 M sucrose and cut into small pieces with a scissors. The tissue was washed with ice-cold 0.25 M sucrose solutions several times. The placental tissue was collected by filtration through two layers of cheese cloth. Placental tissue (2.5 g) was washed and homogenized in 47.5 ml of ice-cold 0.25 M sucrose.Incubation of Placenta. Five milliliters of placental homogenate was placed in a 125-ml Erlenmeyer flask; 2.5 ml of 0.1 M phosphate buffer (pH 7.4) containing 22.2 mM glucose 6-phosphate, 20 mM ATP, 160 mM nicotinamide, and 0.4 mM NADP was then added. In addition, 2.5 ml of a salt solution containing 5 mM magnesium acetate, 0.1 M potassium acetate, and 0.5 units of glucose-6-phosphate dehydrogenase (Sigma) was added. The reaction was initiated by the addition of 300 ,ug of 25-OH-D3 dissolved in 50 ,l of 95% ethanol. Ten flasks prepared in the same way were incubated at 37°C for 1 hr. The reaction was stopped by the addition of 20 ml of methanol/ chloroform (2:1).Extraction of Incubation Media. The contents from 10 flasks were combined and extracted by the method described by Lund and DeLuca (9). The resulting chloroform extract was filtered through Whatman 1 phase-separating filter paper and evaporated to dryness under reduced pressures. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.

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confidence: 99%

“…Gray et al (7) also provided evidence that a possible site of biosynthesis is the placenta. Recently we have developed methods for measuring mammalian 25-OH-D3-la-hydroxylase activity and, therefore, proceeded to test directly the hypothesis put forth by Weisman et al (6) and by Gray et al (7).…”

mentioning

confidence: 99%

In vitro production of 1,25-dihydroxyvitamin D3 by rat placental tissue.

Tanaka¹,

Halloran²,

Schnoes³

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

131

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“…4). Following the reports of Weisman et al [5], Gray et al [6], and Tanaka et al [7], kidney is no longer considered to be the sole site of 25-(OH)D,-1 a-hydroxylation during pregnancy. Several studies have reported that the term human feto-placental unit can produce 1,25-(OH),D, [8-131.…”

Section: Resultsmentioning

confidence: 99%

“…This concept is based on experimental results showing that 1,25-(OH)*D3 is no longer formed after bilateral nephrectomy [l]. However, this is clearly not the case during pregnancy, as rat maternal blood contains 1,25-(OH),D, even after experimental bilateral nephrectomy [5,6], and as foeto-placental tissues from both animals and humans synthesize 1,25-(OH),D, in vitro [7-131. Studies on the ability of the human uterine cells to synthesize 1,25-(OH),D, have so far been mostly limited to the late pregnancy period [g-13], and/or have involved incubations with whole tissue homogenates [8,9,12,13]. The location and characterization of the cells responsible for the 1,25-(OH),D, synthesis in the feto-placental unit at this time of pregnancy remains a fertile field for debate [8-131.…”

Section: Introductionmentioning

confidence: 99%

Uterine cells other than stromal decidual cells are required for 1,25‐dihydroxyvitamin D₃ production during early human pregnancy

Kachkache¹,

Rebut-Bonneton²,

Cynober³

et al. 1993

FEBS Letters

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Human decidual cells are known to produce l,25-(OH)2Dg at the end of pregnancy, the present study evaluates this capacity, and the part played by stromal decidual cells, in early pregnancy. Cells were obtained from nine human decidua by aspiration or curettage during early pregnancy (7-10 weeks), separated on Ficoll-Paque and plastic adherence, and incubated for 1 h with 25-(OH)D1. Incubation medium and cells were extracted and chromatographed on two successive HPLC systems. The cells examined were of both physiological and pathological (ectopic pregnancy) origin. Endometrial cells obtained in four non-pregnant situations (myomas) were also studied to determine whether the l,25-(OH)zD, synthesis by the uterus is associated with the appearance of decidual cells. Results show that human decidual cells from early pregnancy convert 25(OH)D, (2.5 nM or 2.5 PM) into a metabolite with the physicochemical characteristics of synthetic 1,25-(OH),D,. This ability is shared by cells isolated during early pregnancy, whether physiological or ectopic (tubal pregnancy). Non-adherent cells, which include mainly stromal decidual cells, are less able to produce 1,25-(OH),D, than are the adherent cells, suggesting that macrophages, granulocytes or as yet unidentified cell types are required for the l,25-(OH)2D, production by decidual tissue during early human pregnancy. In addition, one out of four experiments with non-pregnant endometrial cells could produce 1,25-(OH),D, suggesting that, although not the rule in the non-pregnant state, in vitro production of l,25-(OH)2Dg by uterine cells can be found in the absence of decidual cells.

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“…Vitamin D regulates serum calcium (Ca) and phosphate (Pi) levels through stimulation of intestinal transport and through mobilization of bone mineral. However, there is still controversy about which role vitamin D plays in regulating Ca and P1 homeostasis during pregnancy (Weisman, Vargas, Duckett, Reiter & Root, 1978; Gray, Lester & Lorenc, 1979;Halloran & DeLuca, 1979). In addition to being transported across the intestinal mucosa, Ca and Pi have to be transported across the placenta during pregnancy to provide adequate supply to the fetus and to ensure fetal Ca and Pi homeostasis.…”

Section: Introductionmentioning

confidence: 99%

ROLE OF 1,25‐(OH)₂D₃ DURING PREGNANCY; STUDIES WITH PIGS SUFFERING FROM PSEUDO‐ VITAMIN D‐DEFICIENCY RICKETS, TYPE I

Lachenmaier-Currle¹,

Breves

Harmeyer³

1989

Exp Physiol

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Synthesis of 1,25-Dihydroxyvitamin D in the Nephrectomized Pregnant Rat*

Cited by 101 publications

References 11 publications

In vitro production of 1,25-dihydroxyvitamin D3 by rat placental tissue.

In vitro production of 1,25-dihydroxyvitamin D3 by rat placental tissue.

Uterine cells other than stromal decidual cells are required for 1,25‐dihydroxyvitamin D₃ production during early human pregnancy

ROLE OF 1,25‐(OH)₂D₃ DURING PREGNANCY; STUDIES WITH PIGS SUFFERING FROM PSEUDO‐ VITAMIN D‐DEFICIENCY RICKETS, TYPE I

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Synthesis of 1,25-Dihydroxyvitamin D in the Nephrectomized Pregnant Rat*

Cited by 101 publications

References 11 publications

In vitro production of 1,25-dihydroxyvitamin D3 by rat placental tissue.

In vitro production of 1,25-dihydroxyvitamin D3 by rat placental tissue.

Uterine cells other than stromal decidual cells are required for 1,25‐dihydroxyvitamin D3 production during early human pregnancy

ROLE OF 1,25‐(OH)2D3 DURING PREGNANCY; STUDIES WITH PIGS SUFFERING FROM PSEUDO‐ VITAMIN D‐DEFICIENCY RICKETS, TYPE I

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Uterine cells other than stromal decidual cells are required for 1,25‐dihydroxyvitamin D₃ production during early human pregnancy

ROLE OF 1,25‐(OH)₂D₃ DURING PREGNANCY; STUDIES WITH PIGS SUFFERING FROM PSEUDO‐ VITAMIN D‐DEFICIENCY RICKETS, TYPE I