AJP - Renal Physiology, Vol 249, Issue 6 836-F841, Copyright © 1985 by American Physiological Society
Metabolic responses of the kidney in fetal sheep: effect of acute and spontaneous hypoxemia
H. S. Iwamoto and A. M. Rudolph
To examine the effects of hypoxemia on carbohydrate and O2 consumption by
the fetal kidney, we inserted catheters into the descending aorta, inferior
vena cava, and left renal vein of 14 fetal sheep at 120-130 days gestation.
Three to nine days after surgery, nine fetuses had an arterial PO2 of 22
+/- 2 mmHg and O2 content of 2.68 +/- 0.65 mM. In these fetuses, the
kidneys consumed O2 (107 +/- 21 mumol X min-1 X 100 g-1, mean +/- SD) and
lactate (14 +/- 9.6 mumol X min-1 X 100 g-1) but produced glucose (5.6 +/-
6.5 mumol X min-1 X 100 g-1; 95% confidence limits, 0.62 and 10.5). When
acute hypoxemia was induced by decreasing maternal fractional inspired O2
(FIO2) to 0.09, renal O2 consumption fell slightly (to 82 +/- 21 mumol X
min-1 X 100 g-1), and there was net glucose uptake and net lactate release.
A group of five fetuses was spontaneously hypoxemic 3-5 days after surgery
and had an arterial PO2 of 14 +/- 2 mmHg and O2 content of 1.99 +/- 0.51
mM. Renal blood flow and O2 consumption were greater in these fetuses than
in the normoxemic fetuses. There was net lactate uptake and no net flux of
glucose across the renal circulation. These results demonstrate that renal
metabolism of carbohydrate is altered by changes in fetal oxygenation.
