Effects of cyclic nucleotide monophosphates (cAMP, cGMP, cIMP, dibutyry-cAMP) on transtubular net fluxes in rat kidneys.

The direct effects of dibutyryl-cAMP, cAMP, cGMP, and cIMP on transepithelial net transfer of fluid and sodium was investigated in proximal tubules of rat kidneys using the split drop method. The cyclic phosphates were applied into the tubular lumen. All four investigated cyclic nucleotide monophosphates diminished the net transport, although high concentrations were necessary. 10 M db-cAMP decreased transtubular net flux of fluid per area tubular surface significantly by 14%. In agreement with other studies, it is concluded that hormones and drugs may influence renal excretory performance via cyclic nucleotide phosphates. [ABSTRACT FROM AUTHOR]