Reabsorption and secretion of p-aminohippurate and Diodrast in Necturus kidney

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Abstract
Renal tubular transport of p-aminohippurate (PAH) and Diodrast was studied in intact pithed Necturi and kidneys perfused in situ. Intact Necturi spontaneously show net reabsorption, no net transport, or net secretion of these compounds. Net reabsorption was converted to net secretion by intra-arterial doses of fatty acids such as octanoate. In kidneys perfused with modified Ringer solution, strong net PAH reabsorption was invariably observed; with 1 m[image] octanoate, net secretion was usually produced. The action of octanoate is specific and reversible. With PAH-carboxyl-C-14 perfused from either the aortic or renal portal side and unlabeled PAH from the opposite side, urine PAH specific activity differed from that of filtered PAH. Unidirectional PAH movements, calculated using a 2-compartment analysis, suggest that Diodrast inhibits reabsorptive and secretory movements, whereas octanoate inhibits primarily the reabsorptive movement. It is suggested that tubular transport of PAH and Diodrast in Necturus kidney involves active processes which move these compounds into proximal tubule cells from luminal and peritubular sides.