HYDROLYSIS AND METABOLISM OF N-BENZOYL-L-TYROSYL-P-AMINOBENZOIC ACID IN NORMAL AND PANCREATIC DUCT-LIGATED ANIMALS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 206  (2) , 468-474
Abstract
Hydrolysis and metabolism of N-benzoyl-L-tyrosyl-p-aminobenzoic acid (Bz-ty-PABA), a synthetic peptide used for the assessment of exocrine pancreatic function, were studied in normal and pancreatic duct-ligated rats and guinea pigs. Bz-ty-PABA was specifically cleaved by chymotrypsin to N-benzoyl-L-tyrosine and p-aminobenzoic acid (PABA) in mucosal homogenates of the intestine. Both of the resultant products were rapidly absorbed and excreted in the urine after oral administration of 2 kinds of radioactive Bz-ty-PABA (Bz[14C] and PABA[14C]) to animals. The absorption rate was correlated to the intestinal chymotrypsin activity obtained from in vitro studies. Benzoic acid and p-acetaminobenzoic acid were predominant in the urine after dosages of Bz-ty-PABA with Bz[14C] and PABA[14C], respectively, in both species. Additionally, a small amount of unchanged form of Bz-ty-PABA was excreted in the urine and bile without being cleaved by chymotrypsin. The absorption of this intact peptide may be almost 10% of the dose.

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