Development of renal tubular transports of TEA and PAH in the puppy and piglet.

RENNICK, BARBARA, BYRON HAMILTON, AND ROBERT EVANS. Development of renal tubular transports of TEA and PAH in the PupPy and piglet. Am. J. Physiol. 201(a): 743-746. I g6 I .-Simultaneous accumulations in renal cortical slices of tetraethylammonium and p-aminohippurate were studied. Slices were obtained from fetal puppies and newborns. Newborns were sacrificed at intervals from birth to g weeks. Slice-to-medium ratios (S/M) were compared for adult, pregnant, and postpartum dog renal slices. Newborn piglets’ kidneys were studied similarly. It was found that these two transport systems developed independently in the fetal and newborn puppy. The transport of TEA was low at birth and progressively rose to the adult value at g weeks. The PAH transport system was active in fetal and newborn tissues. Transports of both TEA and PAH were absent under anaerobic conditions. Acetate stimulated TEA and PAH slice uptakes to the same extent as in the adult. In the piglet the surface slice of the kidney showed low transports of TEA and PAH for the first 2 weeks. At 4 weeks both transport systems increased to equal those in the slices of the lower cortex. The lower cortical slices accumulated TEA and PAH from birth to 8 weeks of age at a fixed rate. The TEA S/M in the piglet at birth was more than twice that in the dog. PAH was accumulated in a predominantly conjugated but unidentified form in the piglet kidney slice.