CONTRACTILE GLOMERULAR RESPONSE IN EXPERI MENTAL DIABETIC NEPHROPATHY

Diabetic nephropaty, in the initial stages, is characterized by hyperf iltration and proteinuria. The mechanism underlying this hyperfiltrati on is not fully understood, but it is possible that it could be due, a t least partially, to a decreased response of glomerular structures to some vasoconstrictor mediators. It has been suggested that captopril can decrease the diabetes-related proteinuria by lowering the hyperfil tration. In our experiments, we tried to assess the contractile respon se of glomeruli from control rats, diabetic rats and diabetic rats rec eiving captopril, in the presence of some vasoconstrictor agonists (An giotensin II, Platelet Activating Factor, Epidermal Cell Growth Factor and Phorbol Myristate Acetate). In all cases we observed a smaller co ntractile response in diabetic glomeruli than in controls. Likewise, w e saw a trend of captopril treatment to normalize this smaller respons e, but differences did not reach statistical significance in all cases . In summary, our results show that the smaller contractile response o f diabetic glomeruli, seems to be due to an alteration in the intracel lular mechanisms of contraction. At least partially, the beneficial ef fect of captopril under these circumstances, could lie in a partial im provement of this defect.