REGULATION OF CGMP PRODUCTION BY INTRACELLULAR ALKALINIZATION IN CULTURED RAT INNER MEDULLARY COLLECTING DUCT CELLS

We evaluated the relationship between cell pH and cGMP production in cultured rat renal inner medullary collecting duct cells. The cGMP level, 21±6, was not different in control vs. alkalinized cells, 49±17 fmol/mg protein (p>0.5). 10-11M atrial natriureitic peptide (ANF) enhanced cGMP production in alkalinized cells, 426±34 vs. 141±9{black star}. Conversely, alkalinization inhibited 10-4M nitroprusside (SNP) induced cGMP formation, 29±9 vs. 332±67{black star}. Phosphodiesterase inhibition abolished the difference in cGMP production by ANF but did not reverse the inhibitory effect of alkalinization on SNP induced cGMP production. In rat renal inner medullary collecting duct cells, cellular alkalinization plays a significant role in the regulation of guanylate cyclase mediated cGMP production. {black star}=p<0.05. © 1990.