Nancy B. Clark

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Brush-border and basolateral membrane vesicles (BBMV and BLMV, respectively) were prepared from chick kidney by a calcium precipitation method and by centrifugation on an 8% Percoll self-generating gradient, respectively. In BBMV a 100-mM Na gluconate gradient, out greater than in, caused concentrative sulfate uptake approximately fivefold greater at 1 min(More)
CLARK, NANCY B., AND WILLIAM H. DANTZLER. Renal tubular transport of calcium and phosphate in snakes: role of parathyoid hormone. Am. J. Physiol. 223(6) : 1455-1464. 1972.-Excretion of calcium and phosphate was studied by clearance techniques in control and parathyroidectomized, unanesthetized water snakes of the genus Matrix. In intact animals, relative(More)
Renal excretion of phosphate, calcium, sodium, and potassium in intact and parathyroidectomized male Rana pipiens was studied by renal clearance techniques using 14C-inulin. In intact frogs, 57% of filtered phosphate, 60% of filtered calcium, 97% of filtered sodium, and 89% of filtered potassium was reabsorbed by the renal tubules. Following(More)
Renal clearance studies were performed in chicks 1, 5, and 9 days after hatching. Calcium gluconate was infused to block endogenous parathyroid hormone (PTH) secretion, whereas ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) was infused to stimulate endogenous PTH secretion. PTH, dibutyryl adenosine 3',5'-cyclic monophosphate(More)
The chorioallantoic membrane (CAM) of the chick embryo actively transports calcium from the egg shell into the embryonic circulation. To investigate the intracellular pathway of calcium transport across the CAM, ultrastructural localization of intracellular calcium in cells of the chorionic ectoderm (CE) was determined using cytochemical methods and X-ray(More)
The yolk sac membrane (YSM) of the chick embryo transports calcium from the yolk into the embryonic circulation during the first half of development, but the intracellular pathway of calcium transport is poorly understood. In the present study, the ultrastructural localization of calcium was investigated in cells of the YSM of 9-day chick embryos. X-ray(More)