Urinary excretion of 25-hydroxyvitamin D in health and the nephrotic syndrome

J Lab Clin Med. 1982 Mar;99(3):325-30.

Abstract

Patients with the nephrotic syndrome may exhibit low serum 25-OH-D concentrations. We developed a method for isolation of 25-OH-D from urine, with measurement by competitive binding assay. Daily urinary 25-OH-D excretion in healthy subjects averaged 0.17 +/- 0.15 nmol/day. Among nephrotic patients, urinary 25-OH-D excretion ranged from 0.27 to 10 nmol/day, in direct relation to the severity of proteinuria (r=0.76) and averaged 3.7 +/- 3.5 nmol/day. The 25-OH-D in the urine of nephrotic patients was unconjugated, implying that it was excreted with the serum VDBG, which has been shown to have a molecular weight and isoelectric point similar to that of albumin. We conclude that low serum 25-OH-D concentrations among nephrotic patients are principally the result or urinary losses of steroid. (J Lab Clin Med 99:325, 1982.)

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 25-Hydroxyvitamin D 2
  • Adult
  • Aged
  • Creatinine / metabolism
  • Ergocalciferols / analogs & derivatives*
  • Ergocalciferols / urine
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nephrotic Syndrome / urine*
  • Proteinuria / metabolism
  • Serum Albumin / metabolism

Substances

  • Ergocalciferols
  • Serum Albumin
  • 25-Hydroxyvitamin D 2
  • Creatinine