RESUMO
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.
Assuntos
Dieta , Di-Hidroxicolecalciferóis/uso terapêutico , Hipocalcemia/tratamento farmacológico , Fósforo/administração & dosagem , 24,25-Di-Hidroxivitamina D 3 , Fosfatase Alcalina/sangue , Animais , Doenças Ósseas/tratamento farmacológico , Doenças Ósseas/etiologia , Osso e Ossos/análise , Calcinose/etiologia , Cálcio/sangue , Cálcio/metabolismo , Hipocalcemia/etiologia , Rim/análise , Masculino , Osteoporose/etiologia , Fósforo/metabolismo , Ratos , Ratos Endogâmicos , Restrição FísicaRESUMO
Effects of prednisolone on the biochemical indices of blood serum, ash content in bones, calcium absorption and calcium-binding protein (CaBP) in the intestinal mucosa were studied. The oral administration of prednisolone (10 mg/kg) for 2 weeks reduced CaBP content and calcium absorption to the level typical for D-avitaminosis. The oral administration of 1 alpha-hydroxycholecalciferol (390 pmoles/day) in combination with prednisolone for a week returned calcium absorption and CaBP to the control value.
