Influence of vitamin D status on insulin secretion and glucose tolerance in the rabbit

Endocrinology. 1984 Jul;115(1):191-7. doi: 10.1210/endo-115-1-191.

Abstract

The influence of vitamin D status on insulin secretion and glucose tolerance was studied by a longitudinal design in the rabbit. Intravenous glucose tolerance tests were performed in Dutch rabbits (n = 12) before and after nutritional vitamin D deficiency, characterized by an absence of circulating 25-hydroxyvitamin D3, a 50% decrease in 1,25-dihydroxyvitamin D3, and a 16% decrease in serum calcium concentrations. Glucose-induced insulin secretion was reduced by 41% as early as 2 months after the start of the vitamin D-deficient diet and was associated with an impairment of glucose tolerance. An iv calcium infusion restored the serum calcium concentration of the vitamin D-deficient rabbits (n = 5), but did not improve glucose-mediated insulin secretion. When these animals received a single ip injection of 100 ng 1,25-dihydroxyvitamin D3 10 h before the glucose test, their insulin responses significantly increased. Supplementation with 25-hydroxyvitamin D3 for 2 weeks in another group of rabbits (n = 4) resulted in marked improvement in glucose-stimulated insulin release and glucose tolerance. These results show that vitamin D affects glucose-induced insulin secretion by a mechanism that involves more than its regulating action on serum calcium concentration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcifediol / blood
  • Calcifediol / therapeutic use
  • Calcitriol / blood
  • Calcitriol / therapeutic use
  • Calcium / blood
  • Calcium / pharmacology
  • Female
  • Glucose Tolerance Test*
  • Insulin / metabolism*
  • Insulin Secretion
  • Kinetics
  • Male
  • Parathyroid Hormone / blood
  • Rabbits
  • Vitamin D Deficiency / drug therapy
  • Vitamin D Deficiency / metabolism*

Substances

  • Insulin
  • Parathyroid Hormone
  • Calcitriol
  • Calcifediol
  • Calcium