Margaret Mylle

Evidence That the Mammalian Nephron Functions as a Countercurrent Multiplier System

Fluid collected by micropuncture from the bend of the loop of Henle in the concentrating hamster kidney had the same osmotic pressure as fluid from a collecting duct at the same level, while that from the distal convolution was more dilute. This indicates that the tubular fluid is first concentrated, then diluted, before its final concentration.

Micropuncture Study of Water Reabsorption and PAH Secretion in Urea Diuresis in Rats.

Summary Inulin and PAH concentrations and osmolalities were determined in samples of tubular fluid collected from surface convolutions of rat kidneys during urea diuresis. F/P inulin ratios averaged 1.6 for the proximal tubule, 2.9 for the distal convolution and 21.7 for the ureteral urine, all significantly lower than in nondiuretic rats. Net PAH secretion appeared to be confined to the proximal tubule and could not be demonstrated in other parts of the nephron.