Effect of oestrogen and 1,25-dihydroxycholecalciferol on 25-hydroxycholecalciferol metabolism in primary chick kidney-cell cultures

Spanos, E.; Barrett, Doreen; Chong, K T; MacIntyre, I.

doi:10.1042/bj1740231

Cited by 54 publications

(16 citation statements)

References 20 publications

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“…Perhaps the extracellular calcium concentration had little influence on the intracellular calcium concentration in these experiments. However, a number of studies have reported that PTH stimulates 1,25(OH)2D3 production by intact renal cells in vitro (30,31,(33)(34)(35)(36)(37). Stimulation ofthe renal la-hydroxylase in these reports required 2-200 ng/ml PTH, the same concentration range that increased the amount of 1,25(OH)2D3 in keratinocytes incubated with 250HD3.…”

Section: Resultsmentioning

confidence: 99%

1,25-Dihydroxyvitamin D3 production by human keratinocytes. Kinetics and regulation.

Bikle¹,

Nemanic²,

Gee³

et al. 1986

J. Clin. Invest.

253

119

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Section: Resultsmentioning

confidence: 99%

1,25-Dihydroxyvitamin D3 production by human keratinocytes. Kinetics and regulation.

Bikle¹,

Nemanic²,

Gee³

et al. 1986

J. Clin. Invest.

253

119

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“…Their free 1,25-(OH)2D3 concentration and their intestinal calcium absorption, however, both remained unchanged, indicating that the biological response of the target organ corresponds to the free rather than the total hormone concentration (36). If the increase in serum 1,25-(OH)2D3 is only secondary to the increase in serum DBP, it becomes clear why the stimulatory effect of estrogens on 1,25-(OH)2D3 production in vivo (37,38) cannot be observed in cultures of isolated kidney cells (39,40).…”

Section: Resultsmentioning

confidence: 99%

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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“…The development of kidney cell cultures by our laboratory and by others (32)(33)(34)(35)(36) has for the first time offered a system for the investigation in vitro of long- (34,35), and steroid hormones (36) have been reported. In our system we have studied the properties of the hydroxylases in cultured cells and we have found that they were similar to those ofthe enzymes in fresh chick kidney preparations.…”

Section: Discussionmentioning

confidence: 99%

Regulation of the metabolism of 25-hydroxyvitamin D3 in primary cultures of chick kidney cells.

Trechsel¹,

Bonjour²,

Fleisch³

1979

J. Clin. Invest.

139

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A B S T R A C T A primary chick kidney cell culture is described, capable of forming 1,25-dihydroxyvitamin D3 [1,25(OH) (OH)D3). Under the latter condition, the sensitivity to bovine parathyroid hormone was enhanced, 0.04 U/ml producing a maximum response. Synthetic aminoterminal tetratriacontapeptide human parathyroid hormone was equally effective. In the absence of D metabolites, estradiol for 6 h produced a dose-dependent inhibition ofthe 1-hydroxylase, but no change in the 24-hydroxylase. Progesterone, testosterone, and corticosterone had no significant effect. In cultures grown in the presence of 25(OH)D3 no reproducible effects were obtained with either 1 ,uM estradiol or 1 ,uM testosterone, alone or in combination, but 5 ,uM corticosterone decreased the 1-and increased the 24-hydroxylase. Changes in Ca and P concentrations of the medium as well as addition of ethane-1-hydroxy-1,1-diphosphate for 48 h did not affect any of the Part of this work was presented at

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Effect of oestrogen and 1,25-dihydroxycholecalciferol on 25-hydroxycholecalciferol metabolism in primary chick kidney-cell cultures

Cited by 54 publications

References 20 publications

1,25-Dihydroxyvitamin D3 production by human keratinocytes. Kinetics and regulation.

1,25-Dihydroxyvitamin D3 production by human keratinocytes. Kinetics and regulation.

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

Regulation of the metabolism of 25-hydroxyvitamin D3 in primary cultures of chick kidney cells.

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