An exocrine pancreatic function test using secretin-chole-

cystokinin or caerulein is considered the best test possible because of its high sensitivity and specificity. However, this test is complex, time consuming, unpleasant for the patient and not feasible in some cases. Therefore, many alternative methods have been developed, such as the p-aminobenzoic acid and fluorescein dilaurate tests, serum trypsin and faecal chymotrypsin concentrations, and enzyme linked immunosorbent assay for elastase in feces. The ideal exocrine pancreatic function test, however, would be sensitive, specific, easy to perform, non-invasive and inexpensive. On the other hand, C-breath tests have been developed as a nonradioactive alternative method. Ghoos and colleagues developed a breath test in 1993 to monitor gastric emptying using C-labelled acetic acid. In 2007, Kohno and colleagues synthesized C-dipeptide, N-benzoyl-L-tyrosyl1-C-L-alanine sodium, and evaluated pancreatic exocrine function by administering N-benzoyl-L-tyrosyl-1-C-L-alanine sodium dissolved in distilled water to anesthetized or conscious rats. However, it is important to perform a breath test non-invasively while the animal is in a conscious and physiologically functioning state. Nutrients in the test meal also affect the pancreatic exocrine function. Recently, we developed a simple breath test system for monitoring gastric emptying non-invasively using Racol (an enteral nutritional formula) containing C-labeled acetic acid in conscious rats. Racol has been used in clinics to investigate the gastric emptying. This study thus aimed to evaluate the pancreatic exocrine function using Racol containing N-benzoyl-L-tyrosyl-1-C-L-alanine sodium and a recently developed simple and non-invasive breath test system. On the other hand, pancreatic exocrine function is known to be low in patients of pancreatitis. However, the effect of diabetes on the pancreatic exocrine function has not been clarified particularly in experimental animals. To evaluate the usefulness of the present method, this function was thus investigated in the alloxan-induced diabetic rats. In diabetic patients, the gastric emptying rate is known to be delayed. To determine the effect of pancreatic insufficiency resulting from diabetic mellitus due to the slower gastric emptying rate, we further tested the effect of this condition on the change of expired air from 1-C-L-alanine which is digested by pancreatic enzymes from N-benzoyl-L-tyrosyl1-C-L-alanine sodium.