ABSTRACT
Male Wistar rats that were experimentally hypokinetic were fed 24,25(OH)2D3 or 1,25(OH)2D3 separately or in combination to determine the effect on bone growth and on bone formation and resorption. It was shown that these parameters of bone metabolism are influenced by these metabolites of vitamin D3 by their effect on bone sensitivity to their activity and perhaps in the regulation of bone histogenesis.
Subject(s)
Bone Development , Calcium Metabolism Disorders/physiopathology , Cholecalciferol/metabolism , Immobilization , Phosphorus Metabolism Disorders/physiopathology , 24,25-Dihydroxyvitamin D 3 , Animals , Bone Development/drug effects , Calcitriol/pharmacology , Dihydroxycholecalciferols/pharmacology , Epiphyses/growth & development , Femur/growth & development , Growth Plate/pathology , Male , Movement , Rats , Rats, Inbred StrainsABSTRACT
Severe hypokinesia of rats given the diet with a ratio of Ca:P = 1:0.5-1:3 was accompanied by hypocalcemia, development of osteoporosis, and some intensification of renal calcinosis. The decrease of phosphorus consumption (Ca:P = 1:0.5-1:1) prevented a development of these changes in intact animals and increased bone mineralization in hypokinetic ones. Excessive phosphorus consumption (Ca:P = 1:3) produced hypocalcemia, hyperphosphatemia, and some osteoporotic changes in the bones of intact animals and intensified these changes with hypokinesia. Administration of 24,25-dihydroxycholecalciferol, an active metabolite of vitamin D3, at a dose of 1.25 micrograms/d prevented a development of bone disorders, thus effectively stimulating diaphyses and epiphyses mineralization and correcting hypocalcemia in hypokinetic rats. 24,25(OH)2D3 at the same dose did not intensify nephocalcinosis and produced no toxic symptoms with hypokinetic animals.
Subject(s)
Diet , Dihydroxycholecalciferols/therapeutic use , Hypocalcemia/drug therapy , Phosphorus/administration & dosage , 24,25-Dihydroxyvitamin D 3 , Alkaline Phosphatase/blood , Animals , Bone Diseases/drug therapy , Bone Diseases/etiology , Bone and Bones/analysis , Calcinosis/etiology , Calcium/blood , Calcium/metabolism , Hypocalcemia/etiology , Kidney/analysis , Male , Osteoporosis/etiology , Phosphorus/metabolism , Rats , Rats, Inbred Strains , Restraint, PhysicalABSTRACT
Hypokinesia induces mineral changes, including changes in calcium and phosphorus metabolism, which involve their increased renal excretion, deposition in soft tissues, and development of osteoporosis. These experiments were designed in order to ascertain the role of active metabolites (hydroxy-cholecalciferol) and changes in phosphorus in the diet on calcium accumulation in bone, soft tissue, and renal calcinosis, and changes in calcium-phosphorus metabolism in rats during prolonged and severe hypokinesia.
Subject(s)
Calcium/metabolism , Diet , Hydroxycholecalciferols/pharmacology , Motor Activity , Phosphorus/metabolism , Animals , Aorta/metabolism , Bone and Bones/metabolism , Calcinosis/etiology , Diet/adverse effects , Kidney/metabolism , Male , RatsABSTRACT
This paper presents data describing the effects of vitamin and amino acid supplements on the health state and performance of men doing heavy mental and physical work. Experiments on seven test volunteers showed that a 20-d intake of a mixture of vitamins, amino acids, and mineral substances optimized the health state and increased the performance of test subjects doing heavy work.
