Hypophosphatemia is responsible for skeletal muscle weakness of vitamin D deficiency.

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.

• Authors: Laurie Schubert, Hector F DeLuca
• Journal: Archives of biochemistry and biophysics (Arch Biochem Biophys) Vol. 500 Issue 2 Pg. 157-61 (Aug 15 2010) ISSN: 1096-0384 [Electronic] United States
• PMID: 20515645 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: 2010 Elsevier Inc. All rights reserved.

Topics

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