Estimation of assimilation of simultaneously ingested 14C-triolein and 3H-oleic acid as a test of pancreatic digestive function.

The ratio between assimilation of simultaneously ingested 14C-triolein and 3H-oleic acid was investigated as a test of pancreatic digestive function in 48 consecutive patients suspected of malassimilation. Faecal excretion of 14C-triolein and 3H-oleic acid was measured by means of a combustion/liquid scintillation counting technique. Compared with the patients in whom the clinical investigation showed normal lipid assimilation (no. = 31) the assimilation of both 14C-triolein and 3H-oleic acid was significantly reduced in the patients with malabsorption (no. = 6) and maldigestion (no. = 11). However, in all except one patient with maldigestion the assimilation of 14C-triolein was more reduced than that of 3H-oleic acid, whereas there was no difference in 14C-triolein and 3H-oleic acid assimilation in the patients with malabsorption and normal lipid assimilation. Measurement of the postprandial serum radioactivities of 14C and 3H, like the faecal measurements, indicated more severely reduced assimilation of 14C-triolein than of 3H-oleic acid in the patients with maldigestion than in the other patient groups. In fact, the 2-h postprandial 3H/14C ratio at a level of 1.3 correctly classified digestive function in 47 of the 48 patients.