title: The influence of interrrupted vitamin D metabolism on acute low calcium adaptation in the rat.
abstract: The small intestine of animals place on a low calcium diet adapts to the dietary restriction by transporting calcium more efficiently. Adaptation has been observed in most mammalian species; however, the mechanism of adaptation has not been well defined. Recent evidence indicates that 1,25-dihydroxycholecalciferol [1,25(OH)2-D3], the active metabolite of vitamin D, may be involved in the process of adaptation. The present study was designed to examine the inflluence of experimental interruption of vitamin D metabolism on acute low calcium adaptation. Partial hepatectomy, cortisone treatment and dietary strontium supplements were used to inhibit the production of 1,25(OH)2-D3. In separate experiments partial hepatectomy produced a 38% reduction in adaptation; cortisone treatment (5 mg/day, s.c.) caused a 88% reduction and dietary strontium abolished adaptation completely. The possible roles of parathyroid hormone and 1,25(OH)2-D3 and their relationships in the process of adaptation are discussed.
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003348:Cortisone / Q000494:pharmacology; D006498:Hepatectomy; D008297:Male; D051381:Rats; D013324:Strontium / Q000494:pharmacology; D014807:Vitamin D / Q000378:metabolism*
chemical_list: D014807:Vitamin D; D002118:Calcium; D003348:Cortisone; D013324:Strontium