2ND-MESSENGER CHANGES OF ATRIAL-NATRIURETIC-FACTOR AND BRAIN NATRIURETIC PEPTIDE IN KIDNEYS OF CARDIOMYOPATHIC HAMSTERS

The effects of natriuretic peptides in kidney are blunted in congestiv e heart failure (CHF). The aim of this study is to examine the changes of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP ) second messenger productions in CHF. Experiments were conducted on 3 00-day-old normal and cardiomyopathic hamsters. Blood was collected fo r ANF measurement. cGMP accumulation studies were done in glomeruli up on ANF and BNP stimulation, and in inner medullary collecting duct (IM CD) cells upon ANF stimulation. Higher plasma ANF levels were found in cardiomyopathic hamsters (811.3 +/- 124.6 vs. 166.6 +/- 13 pg/ml, p < 0.01). ANF-stimulated cGMP accumulations in glomeruli and IMCD cells were higher in cardiomyopathic hamsters. Increased BNP-stimulated cGMP accumulations were also observed in cardiomyopathic hamster glomeruli . These results suggest that the renal hyporesponsiveness to natriuret ic peptides in CHF is not due to attenuated ANF and BNP second messeng er productions.