RESUMO
We have identified a plasmatic substance, "pepsanurin" (PU) obtained by pepsin hydrolysis which inhibits the renal effects of the atrial natriuretic factor (ANF). To investigate whether patients with congestive heart failure (CHF) have increased plasma levels of PU we prepared PU from 10 patients with CHF class IV (NYHA), 9 patients with CHF class II or III and 16 healthy controls. Anesthetized rats were used to test the effects of ANF, 0.5 ug/100 g body weight i.v., before and following the intraperitoneal injection of 0.5 ml of PU. The inhibition of the diuretic and natriuretic effects of ANF was 40.9 ñ 11.9% and 49.8 ñ 12% respectively for control subjects. Corresponding figures for clas CHF patients were 62.3 ñ 3.1% and 73.8 ñ 3.5% (p < 0.02) and for class II-III patients 39.2 ñ 7.0% and 53.1 ñ 8.2% (NS). Accordingly, an increased capacity to generate PU may underlie the decreased sensitivity to ANF in patients with advanced CHF