Vitamin D Deficiency, hypocalcemia, and increased skeletal muscle degradation in rats

J Clin Invest. 1983 Jul;72(1):102-12. doi: 10.1172/jci110947.

Abstract

The myopathy associated with vitamin D deficiency was examined in vitamin D-deficient and vitamin D-supplemented rats. When compared with either vitamin D-supplemented ad lib. or pair-fed rats, weight gain and muscle mass were decreased in vitamin D-deficient hypocalcemic animals. With the exception of a modest decrease in muscle creatine phosphate levels, muscle composition was unchanged by vitamin D deficiency. Muscle protein turnover rates were determined in both in vivo and in vitro studies and demonstrated that myofibrillar protein degradation was increased in vitamin D deficiency. Normal growth rates could be maintained be feeding the rats vitamin D-deficient diets containing 1.6% calcium, which maintained plasma calcium within the normal range. In addition to its role in maintaining plasma calcium, vitamin D-supplemented rats had significantly higher levels of the anabolic hormone insulin. Vitamin D supplementation may affect muscle protein turnover by preventing hypocalcemia, as well as directly stimulating insulin secretion, rather than by a direct effect within skeletal muscle.

Publication types

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

MeSH terms

  • Animals
  • Body Weight
  • Calcium / blood*
  • Calcium / urine
  • Cholecalciferol / therapeutic use
  • Insulin / blood
  • Male
  • Muscle Proteins / metabolism
  • Muscles / metabolism*
  • Phosphocreatine / metabolism
  • Rats
  • Rats, Inbred Strains
  • Vitamin D Deficiency / drug therapy
  • Vitamin D Deficiency / metabolism*

Substances

  • Insulin
  • Muscle Proteins
  • Phosphocreatine
  • Cholecalciferol
  • Calcium