ATTENUATED GLOMERULAR RESPONSES TO ATRIAL-NATRIURETIC-FACTOR IN LOW-SODIUM RATS IS PREVENTED BY THEOPHYLLINE

Atrial natriuretic factor administered in the large dose did not change glomerular filtration rate, but it was diuretic in low-sodium rats. In response to ANF, excretion of c-GMP was decreased in low-sodium rats in comparison with normal-sodium rats. Theophylline prevented glomerular response to ANF. ANF-stimulated c-GMP accumulation in isolated glomeruli was more diminished in low- than normal sodium rats. These results indicate that attenuated glomerular responses to ANF in low-sodium rats might be due to increase of plasma Angiotensin II (Ang II) level, which increases intracellular Ca++ concentration. Theophylline can potentiate the renal response to ANF. We suggest that Ca++-activated c-GMP phosphodiesterase plays a major role in the regulation of intracellular accumulation of c-GMP in glomeruli exposed to ANF. © 1990.