Interactions between the growth effects of a kidney epithelial cell growth inhibitor and extracellular concentrations of cyclic nucleotides.

The effect of dibutyryl cyclic nucleotides, dbcAMP and dbcGMP, on the growth of BSC-1 cells has been studied in the presence and absence of kidney epithelial cell growth inhibitor. The growth response of the cells was dependent on concentrations of the dibutyryl cyclic nucleotides and on the presence or absence of serum in the medium. In the presence of serum, a high concentration (10(-3) M) of dbcGMP largely overcame the action of the kidney epithelial cell growth inhibitor. In the absence of serum, a high concentration (10(-3) M) of dbcAMP increased growth inhibition observed with the growth inhibitor. In the presence of serum, low concentrations of dbcAMP were growth stimulatory and partially overcame the action of the growth inhibitor.