Abstract

Standard tissue-slice techniques have been employed to examine the uptake of the metabolic inhibitor, 2, 4-dinitrophenol (DNP) by rabbit renal cortex. For this study the uptake of C¹⁴-dinitrophenol (C¹⁴-DNP) was monitored. No metabolism of the C¹⁴-DNP by slices of renal cortex was detected with paper chromatography. Steady-state slice/medium ratios of 10 to 15 were attained in 40 to 60 mm. Various metabolic inhibitors (e.g., sodium cyanide, iodoacetamide, p-chloromercuribenzoate) reduced the accumulation significantly. Although some metabolic intermediates (e.g., acetate, glucose) failed to influence the C¹⁴ accumulation, most reduced the uptake. Other organic acids known to be transported by the renal organic anion transport system also inhibited the C¹⁴-DNP uptake (e.g., octanoate, decanoate, p-aminohippurate). Various organic bases were tested but did not influence DNP accumulation. Furthermore, alterations in the potassium ion concentration of the bathing solution did not affect DNP uptake. Also, no pH optimum was found. It was concluded that the accumulation of C¹⁴-DNP occurred by two processes: 1) active uptake by the renal organic acid transport process, and 2) a nonspecific binding or partitioning.