Vitamin D Metabolism and Parathyroid Function in Man

Mawer, E. B.; Backhouse, Joan; Hill, L. R.; Lumb, G. A.; Silva, Priyadarshini de; Taylor, Craig; Stanbury, Sarah

doi:10.1042/cs0480349

Cited by 58 publications

(34 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This compound contains the greatest biological activity of any known vitamin D metabolite (9)(10)(11). Control of renal la,25-(OH)2D synthesis, and consequently the physiological response of vitamin D-dependent processes, is influenced to a large extent by the action of parathyroid hormone (PTH) on the kidney la-hydroxylase system (12)(13)(14). A lesion in this control system can result in the development of disease-states which affect calcium homeostasis (15-17) (e.g., renal-and vitamin D-dependent rickets).…”

Section: Introductionmentioning

confidence: 99%

Kinetic analysis of 25-hydroxyvitamin D3 metabolism in strontium-induced rickets in the chick.

Omdahl¹,

Jelinek²,

Eaton³

1977

J. Clin. Invest.

View full text Add to dashboard Cite

A B S T R A C T Kinetic data analysis was used to derive a six-compartment computer model which describes the in vivo [3H]25-hydroxyvitamin D3 ([3H]25-OHD3) metabolism in control and strontium rachitic chicks. Plasma concentrations of 25-OHD3 (13 pmol/ml) and 24, 25-dihydroxyvitamin D3 (0.9 pmol/ml) were 18 and 125% greater than controls, respectively, whereas the corresponding level for la,25-dihydroxyvitamin D3 (0.3 pmol/ml) was only 30% of control. Plasma disappearance of 25-OHD3 was fitted using a two-compartment model in which the metabolite extrapolated half-life was nearly twice as large for strontium rachitic chicks (71 compared to 41 h). Intestinal sequestration of la,25-dihydroxyvitamin D3 was assumed to be irreversible and was fitted by a single exponential term in which metabolite uptake rate and tissue concentration in strontium rickets was suppressed to 20 and 10% of control, respectively. In contrast, uptake of 25-OHD3 by the intestine was observed to occur by a reversible process in which metabolite concentration was 45% greater in the strontium rachitic compared to control group. The developed compartment model accepts time-dependent control or perturbed metabolite data for the plasma and (or) intestinal pools and provides quantitative values for metabolite pool size, flux rate, and turnover time.

show abstract

Section: Introductionmentioning

confidence: 99%

Kinetic analysis of 25-hydroxyvitamin D3 metabolism in strontium-induced rickets in the chick.

Omdahl¹,

Jelinek²,

Eaton³

1977

J. Clin. Invest.

View full text Add to dashboard Cite

show abstract

“…Liver 25-hydroxylation in the rat appears to be inhibited by high doses of vitamin D (4). It is unclear whether a compensatory increase in hepatic 25-hydroxylation could occur in a situation theoretically predisposing to vitamin D malabsorption (17). Even in the three children with marked falls in plasma 25-OHD to subnormal values, plasma 25-OHD levels reverted to normal in 4-6 months.…”

Section: Discussionmentioning

confidence: 97%

Plasma 25-Hydroxy-vitamin D in Familial Hypercholesterolemic Children Receiving Colestipol Resin

et al. 1978

View full text Add to dashboard Cite

Pediat. Res. 12: 980-982 (1978) Bile acid sequestrant resins (colestipol) 25-hydroxy-vitamin D SummaryIn this study we have assessed effects of Colestipol, a synthetic organic bile sequestrant polymer, on vitamin D metabolism over a 2-year period in children with familial hypercholesterolemia. In the 15 children, mean (+SE) low density lipoprotein (LDL) cholesterol decreased from 221 + 9 mg/dl (baseline), to 181 +-7 after 12-14 months of Colestipol resin, P < 0.01. Thereafter, LDL cholesterol remained in the 170-190 mg/dl range. Mean plasma 25-hydroxyvitamin D (25-OHD) levels appeared to fall slightly and progressively from 32.6 + 4 ng/ml (baseline) to 29.8 + 3.5 at 12-14 months, to 25.6 & 3.3 at 16-18 months, and to 18.5 + 2.7 at 18-20 months. The decrease in plasma 25-OHD was not significant until 18-20 months (paired t, P < 0.01). After 20 months, plasma 25-OHD levels appeared to increase again and were not significantly different from baseline. Seasonal effects on plasma 25-OHD were not demonstrable. Mean plasma Ca values were mildly increased after Colestipol therapy was begun and were significantly elevated at 18-20 months (10.04 vs. 9.71 mg/dl at baseline). Mean plasma PO4 levels were not significantly different on Colestipol therapy, with the single exception that at 20-22 months plasma Po4 was 3.82 vs. 4.05 mg/dl at baseline ( P< 0.05). In no subject was serum Ca <9 mg/dl or serum PO4 <2.5 mg/dl at any time during the study.

show abstract

“…Between the 14th and 7th days before donating plasma, the patient received 900 IU (22.5 pg) calciferol daily; this was to ensure a state of vitamin D repletion, the condition necessary for formation of 24,25(OH),D [6]. On the last day of this pretreatment, when the serum level of 25-OH-D was 16.8 ng/ml, the patient was given an intraveneous injection of 8 /Ki 25-hydroxy-[26,27-3H]cholecalciferol (12 Ci/mmol, Radiochemical Centre, Amersham) in 1 .O ml ethanol dispersed in 9 .O ml Intralipid (Vitrum, Stockholm).…”

Section: Preparation and Purification Of Human Radioactivementioning

confidence: 99%

Stereochemical configuration at C‐24 of 24,25‐dihydroxycholecalciferol of human origin

et al. 1980

View full text Add to dashboard Cite

Vitamin D Metabolism and Parathyroid Function in Man

Cited by 58 publications

References 22 publications

Kinetic analysis of 25-hydroxyvitamin D3 metabolism in strontium-induced rickets in the chick.

Kinetic analysis of 25-hydroxyvitamin D3 metabolism in strontium-induced rickets in the chick.

Plasma 25-Hydroxy-vitamin D in Familial Hypercholesterolemic Children Receiving Colestipol Resin

Stereochemical configuration at C‐24 of 24,25‐dihydroxycholecalciferol of human origin

Contact Info

Product

Resources

About