title: Urinary excretion of purine derivatives in Bos indicus x Bos taurus crossbred cattle.
abstract: Four experiments were performed to study the kinetics of purine metabolism and urinary excretion in Zebu crossbred cattle. Fasting excretion was established in Expt 1, using eighteen male Bos indicus x Bos taurus crossbred cattle (261 (SE 9.1) kg body weight), six of each of the following genotypes: 5/8 Bos indicus, 1/2 Bos indicus and 3/8 Bos indicus. No significant differences were observed among genotypes in fasting purine derivative excretion (277.3 (SE 35.43) micromol/metabolic body weight). In a second experiment we measured the xanthine oxidase activity, which was higher in liver than in duodenal mucosa (0.64 and 0.06 (SE 0.12) units/g wet tissue per min respectively; P>0.05) being in plasma 0.60 (SE 0.36) units/l per min. The kinetics of uric acid were measured by intravenous pulse dose of [1,3-15N]uric acid (Expt 3). The cumulative recovery of the isotope in urine was 82 (SE 6.69) %, and uric acid plasma removal, pool size and mean retention time were 0.284 (SE 0.051) per h, 5.45 (SE 0.823) mmol and 3.52 (SE 0.521) h, respectively. Allantoin was removed from plasma at an estimated fractional rate of 0.273 (SE 0.081) per h and mean retention was 3.66 (SE 1.08) h. In Expt 4, the relationship between urinary purine derivative excretion (Y; mmol/d) and digestible organic matter intake (X, kg/d) was defined by the equation: Y=7.69 (SE 4.2)+5.69 (SE 1.68) X; n 16, Se 1.31, r 0.67.
authors: Instituto de Producción Animal, Facultad de Agronomía, Universidad Central de Venezuela, Maracay Apdo. 4579, Venezuela.
authors: Alvaro
authors: A
authors: Ojeda
authors: Ornella
authors: O
authors: de Parra
authors: Joaquím
authors: J
authors: Balcells
authors: Alvaro
authors: A
authors: Belenguer
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism* / Q000652:urine; D004386:Duodenum / Q000201:enzymology; D004435:Eating / Q000502:physiology; D005215:Fasting / Q000378:metabolism / Q000652:urine; D007422:Intestines / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D011687:Purines / Q000378:metabolism* / Q000652:urine; D014527:Uric Acid / Q000652:urine; D014969:Xanthine Oxidase / Q000097:blood / Q000378:metabolism
chemical_list: D011687:Purines; D014527:Uric Acid; D014969:Xanthine Oxidase