Effect of gastrointestinal surgery and bacterial overgrowth on the urinary excretion of sulfur amino acids and their main degradation products.

The urinary excretion of sulfur amino acids and their main degradation products was determined in patients subjected to various forms of gastrointestinal surgery or with bacterial overgrowth. A normal excretion of total sulfur and inorganic sulfate was found, indicating an adequate intake and maintained ability to absorb sulfur amino acids. An increased excretion of ester sulfate was observed in all groups except patients subjected to ileocecal resection or proctocolectomy, probably owing to bacterial overgrowth. A reduced excretion of methionine was observed in patients with gastric resection (Billroth I), ileocecal resection, and abnormal gut flora, whereas patients with jejunoileal bypass showed an increased excretion of methionine, probably a consequence of the impaired liver function. For cystathionine, a similar effect was found in patients with ileocecal resection and jejunoileal bypass. A reduced excretion of mercaptolactate was found in jejunoileal bypass patients. A low excretion of thiosulfate was seen in proctocolectomized patients, suggesting that the bacterial flora of the colon plays a role in the formation of thiosulfate. A low excretion of thiocyanate was found in gastric-resected patients, which may be due to a decreased ability to hydrolyze cyanogenic and/or thiocyanogenic glycosides or to a reduced intake of these compounds.