Bradykinin-induced changes in phosphatidyl inositol turnover in cultured rabbit papillary collecting tubule cells

Rabbit renal papillary collecting tubule cells were isolated as a homogenous population and grown in primary culture. These cells were maintained in fully defined medium to inhibit fibroblast overgrowth and to facilitate labeling of endogenous inositol phospholipids with myo-[2-³H]inositol with high specific activity. These cells demonstrated the morphology, cyclic AMP responsiveness, and prostaglandin E₂ (PGE₂) elaboration, consistent with previous published characterizations. When cells labeled with myo-2-³H]inositol were stimulated by bradykinin at 10^-7 M, time-dependent and reversible changes in the distribution of inositol polyphosphates were observed. Inositol 1,4,5-triphosphate and inositol 1,4-diphosphate showed time-dependent and dose-dependent increases to maximal levels of 225 and 223% of control, respectively. These data indicate that the elaboration of inositol polyphosphates is a biochemical correlate to bradykinin stimulation and may play a role in PGE₂ release in renal papillary collecting tubule cells.