Hypophosphatemia is responsible for skeletal muscle weakness of vitamin D deficiency

Arch Biochem Biophys. 2010 Aug 15;500(2):157-61. doi: 10.1016/j.abb.2010.05.029. Epub 2010 May 31.

Abstract

A deficiency of vitamin D results in muscle weakness as well as rickets in children and osteomalacia in the adult. To study the basis for this weakness, severe vitamin D deficiency was produced in rats as revealed by a low level or absence of 25-hydroxyvitamin D(3) in the serum. Vitamin D deficiency was achieved by feeding purified diets to weanlings for 16 weeks. Muscle force, peak contraction (P), time-to-half contraction (T(1/2)), time-to-peak contraction (T(P)), and time-to-half recovery (T(1/2r)) were measured. A significant reduction in muscle force was found when vitamin D deficiency was accompanied by hypophosphatemia. Within 2 days of correcting the hypophosphatemia, muscle strength was normalized. When serum calcium and serum phosphorus were maintained in the normal range in vitamin D-deficient rats, muscle weakness did not develop. Further, hypocalcemia together with vitamin D deficiency did not produce muscle weakness. These results strongly suggest that muscle weakness noted in rachitic patients is the result of the hypophosphatemia of vitamin D deficiency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Child
  • Disease Models, Animal
  • Humans
  • Hypophosphatemia / complications*
  • Hypophosphatemia / physiopathology
  • Male
  • Muscle Contraction
  • Muscle Fibers, Fast-Twitch / physiology
  • Muscle Fibers, Slow-Twitch / physiology
  • Muscle Strength
  • Muscle Weakness / etiology*
  • Muscle Weakness / physiopathology
  • Muscle, Skeletal / physiopathology
  • Rats
  • Rats, Wistar
  • Rickets / etiology
  • Rickets / physiopathology
  • Vitamin D Deficiency / complications*
  • Vitamin D Deficiency / physiopathology