title: Fasting gastrinemia and elevated supersaturation with hydroxyapatite of fasting urine--observations in renal calcium stone patients and controls.
abstract: We evaluated serum gastrin, acid-base status, variables of mineral metabolism in fasting blood, as well as pH, relative supersaturation of stone forming constituents, and crystalluria in the associated fasting urine, of control subjects (n = 12), and in age- and weight-matched male normocalciuric (n = 12) and hypercalciuric (n = 12) patients with idiopathic recurrent calcium urolithiasis (RCU). In RCU, mineral metabolism and acid-base data are unchanged, whereas mean serum gastrin is only insignificantly higher as compared to controls. Subclassification of all participants into categories with either high-normal or low-normal gastrin reveals that in RCU with low-normal gastrin there is a higher-than-normal urinary pH and significantly elevated supersaturation of urine with hydroxyapatite. Crystalluria and stone analysis support the assumption that the physico-chemical environment accompanied by low gastrin levels predisposes to urinary precipitation of calcium phosphate with subsequent formation of a stone nidus. pH in fasting urine and integrated fasting serum gastrin correlate significantly, suggesting that low fasting serum gastrin in RCU patients may be considered a risk factor for calcium phosphate stone formation.
mesh_terms: D000136:Acid-Base Equilibrium; D000293:Adolescent; D000328:Adult; D002129:Calcium Oxalate / Q000652:urine; D002130:Calcium Phosphates / Q000652:urine; D011232:Chemical Precipitation; D003460:Crystallization; D017886:Durapatite; D005215:Fasting; D005755:Gastrins / Q000097:blood*; D006801:Humans; D006882:Hydroxyapatites / Q000652:urine*; D007669:Kidney Calculi / Q000209:etiology / Q000378:metabolism*; D008297:Male; D012306:Risk
chemical_list: D002130:Calcium Phosphates; D005755:Gastrins; D006882:Hydroxyapatites; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002129:Calcium Oxalate; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous