Aim: 

Dietary fat composition influences male reproductive function modifying the cholesterol-phospholipid composition of testicular plasma membranes. Modifications in the composition and physical properties of the membranes may lead to alterations in the activities of membrane-bound (M-B) enzymes. We have previously demonstrated that dietary fatty acids with different degrees of saturation modified peptidase activities in the testes of mice. Dipeptidyl peptidase IV (DPP IV/CD26) is structurally bound to prostasomes and may play a critical role in the motility of spermatozoa. Gamma-glutamyl transpeptidase (GGT) appears to play an important role in the protection of spermatozoa from oxidative stress. Therefore, to evaluate the testicular function depending to the type of fat in the diet, we studied DPP IV and GGT activities in the testes of rats fed a standard diet (S), a diet supplemented with olive oil (O) or a diet supplemented with butter plus cholesterol (B).

Methods: 

DPP IV and GGT were measured fluorometrically in their soluble (SOL) and membrane-bound forms using arylamide derivatives as substrates.

Results: 

Soluble DPP IV activity was significantly higher in the O group than S or B. Membrane-bound GGT was significantly higher in the B group compared with S but did not differ from the O group.

Conclusion: 

The present data demonstrate that the type of fat used in the diet affect DPP IV and GGT activities in the testes of rats and consequently may be important in male reproductive functions.