Aim: 

High fat diet has been associated with obesity and type II diabetes. Olive oil intake increases the release of GLP-1, a peptide with insulin-releasing and antidiabetic properties, which may explain in part the protective effect of this fat on type II diabetes. GLP-1, secreted from intestinal L-cells, is rapidly cleaved by dipeptidyl peptidase IV (DPP-IV), a widely distributed enzyme that can be found in blood and several tissues. To test the effects of dietary fatty acids on GLP-1 metabolism, we have determined DPP-IV activity in serum, liver and kidney of rat fed three different diets: standard, supplemented with olive oil or supplemented with butter plus cholesterol.

Methods: 

Animals were fed the experimental diets ad libitum during six months. Soluble and membrane-bound DPP IV activities were measured fluorometrically in serum and tissues using an arylamide derivative (gly-pro-4-methoxy-b-naphthylamide) as substrate.

Results: 

Serum DPP-IV activity was significantly higher (p = 0.045) in the animals fed the diet enriched with olive oil than the rats fed the standard diet. In the liver, we found significantly higher (p = 0.022) membrane-bound DPP IV activity in animals fed the olive oil enriched diet than the ones fed the standard diet. No differences were observed in kidney between the three groups studied.

Conclusions: 

The present data demostrate that the long term intake of olive oil diet increased DPP-IV activity in serum and liver. This may be related with the reported higher levels of GLP-1 in olive oil enriched diet.