Relative and combined effects of ethanol and protein deficiency on bone histology and mineral metabolism

This study was performed to analyze the relative and combined effects of et hanol and protein deficiency on bone histology and mineral metabolism in 4 groups of 7 animals each which were pair-fed during 8 weeks with 1) a nutri tionally adequate diet; 2) a 36% las energy) ethanol containing isocaloric diet; 3) a 2% protein, isocaloric diet; and 4) a 36% ethanol 2% protein iso caloric diet, respectively, following the Lieber-DeCarli model. Another gro up of five rats were fed ad libitum the control diet. The first and second lumbar vertebrae were removed after sacrifice, and processed for histomorph ometrical analysis of undecalcified bone samples. Blood and 24-h urine were also collected. Protein malnutrition, but not ethanol, leads to osteoporos is and reduced osteoid synthesis, whereas ethanol and protein malnutrition both lead to impaired bone mineral apposition and increased urinary hydroxy proline excretion. These changes are accompanied by an increase in serum pa rathormone and serum 1.25 dihydroxy vitamin D3, a slight hypomagnesemia, hy percalciuria and hyperphosphaturia; protein deficiency plays an independent role in these alterations, whereas both ethanol and protein deficiency exe rt independent effects on decreasing serum testosterone levels; this last a lteration may contribute to the bone changes mentioned before. (C) 2000 Els evier Science Inc. All rights reserved.