title: Diet calcium carbonate, phosphorus and acidifying and alkalizing salts as factors influencing silica urolithiasis in rats fed tetraethylorthosilicate.
abstract: Three experiments were conducted to determine the effects of excess dietary calcium carbonate, phosphorus and urine acidifying and alkalizing salts on silica urolith formation in a model using rats fed dextrose-based diets containing 2% tetraethylorthosilicate (TES). Diets containing 2% TES lowered weight gains to 91-95% of gains made by rats fed non-TES diets. Urine silica concentrations of rats fed TES were generally in the range of 50-60 mg/dl. In experiment 1, rats fed TES with no additional dietary calcium carbonate had a silica urolith incidence of 35%. With additions of 1 and 2% calcium carbonate to the basal-TES diet, respective urolith incidences were 45 and 60% (r = 0.99, P less than 0.02). In experiment 2, monobasic sodium phosphate (MP) providing 0.2% additional phosphorus resulted in a mean urine pH of 6.42 and no uroliths. Dibasic sodium phosphate (DP) without and with 0.5% sodium bicarbonate (SB) resulted in respective urine pH values of 6.78 and 7.14 and urolith incidences of 15 and 20% (MP less than DP and DP + SB, P less than 0.05). However, the uroliths were small averaging less than 1 mg. In experiment 3, substitution of autoclaved egg albumin for casein, the protein source in experiments 1 and 2, resulted in urine pH of 7.45 and a silica urolith incidence of 46%. An equal-molar mixture of MP and DP providing an added 0.2% phosphorus resulted in a urine pH of 7.07 and reduced the urolith incidence to 4%, and 0.75% of dietary ammonium chloride either with or without the added 0.2% phosphorus gave urine acidification and complete protection from uroliths.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D001835:Body Weight; D002118:Calcium / Q000097:blood; D002119:Calcium Carbonate / Q000494:pharmacology*; D002254:Carbonates / Q000494:pharmacology*; D004032:Diet; D004347:Drug Interactions; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000097:blood; D008297:Male; D010758:Phosphorus / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D011919:Rats, Inbred Strains; D012821:Silanes / Q000378:metabolism*; D012825:Silicon / Q000378:metabolism*; D012822:Silicon Dioxide / Q000652:urine; D012964:Sodium / Q000494:pharmacology*; D017693:Sodium Bicarbonate; D014545:Urinary Calculi / Q000139:chemically induced* / Q000517:prevention & control
chemical_list: D001639:Bicarbonates; D002254:Carbonates; D012821:Silanes; D010758:Phosphorus; C040733:tetraethoxysilane; D012822:Silicon Dioxide; D017693:Sodium Bicarbonate; D012964:Sodium; D002119:Calcium Carbonate; D008274:Magnesium; C040502:ammonium carbonate; D002118:Calcium; D012825:Silicon