Changes in plasma half-life and clearance of 3H-25-hydroxyvitamin D3 in patients with intestinal malabsorption.

Abstract

SUMMARY The plasma disappearance of intravenously administered tracer doses of tritiumlabelled 25-hydroxyvitamin D3 (250HD3) was studied in six normal subjects and in 15 patients with intestinal malabsorption. The plasma half-life was significantly shorter and the clearance rate significantly greater in the group with malabsorption compared with the controls. One explanation for this increased elimination could be interruption of an enterohepatic circulation of 250HD occurring in subjects with malabsorption and such a mechanism could account for the loss of endogenous vitamin D in these patients.Vitamin D deficiency and osteomalacia occur in a variety of intestinal disordersl13 and are common after jejunoileal bypass (JIB) for obesity.

Vitamin D Deficiency and Nutritional Rickets in Children

“…Over the past 25 years, research has shown that both high-fiber diets and intestinal malabsorption reduce the serum half-life of 25(OH)D by approximately one-third [242,243]. Further, experiments in rats have demonstrated that an elevation in serum 1,25(OH) 2 D concentrations, either by exogenous administration or endogenously through a low-calcium diet, increases the metabolic clearance rate of 25(OH)D without altering its rate of production [244e246].…”

Vitamin D insufficiency in myeloproliferative neoplasms and myelodysplastic syndromes: Clinical correlates and prognostic studies

“…Vitamin D 2 (ergocalciferol) is plant derived and is obtained through the diet or supplementation. For practical purposes, both forms of vitamin D can be considered bioequivalent and undergo the same metabolism, initially to 25- Assessment of vitamin D status is ascertained through the measurement of serum 25(OH)D concentration, rather than 1,25(OH) 2 D, since the former is the most stable and plentiful metabolite and has a half-life of 3 weeks [2]. The precise threshold for defining vitamin D deficiency and vitamin D insufficiency has been a matter of debate, but bone disease resulting from vitamin D deficiency is generally associated with serum 25(OH)D concentrations lower than 10 ng/mL.…”

Vitamin D Deficiency and Seasonal and Inter-day Variation in Circulating 25-hydroxyvitamin D and Parathyroid Hormone Levels in Indoor Daytime Workers: A Longitudinal Study

“…Hiroaki ITOH 1 * , Ippei MORI 1, 2 , Yuki MATSUMOTO 1 , Syou MAKI 1 and Yasutaka OGAWA 1 25-Hydroxyvitamin D (25OHD), a major component of circulating vitamin D metabolites whose biological half-life in blood (2-5 wk in normal subjects) [10][11][12][13][14] is substantially longer than that of vitamin D itself (24 h) 10) , is commonly used as an indicator of individuals' vitamin D status 15) . Exposure to solar ultraviolet (UV) B irradiation changes 7-dehydrocholesterol to previtamin D by photosynthesis in the skin.…”