ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The dependencies of gluconeogenesis and urea synthesis on oxygen concentration were measured in suspensions of isolated rat hepatocytes and compared with the O2 dependence of cellular energy supply (reduction of cytochrome c, respiratory rate, mitochondrial [NAD+]/[NADH], lactate production, and [ATP]/[ADP][Pi]). As the oxygen concentration was decreased, production of both glucose and urea declined; the changes were observable at 20 μM oxygen and below, with the apparent Km values for both processes of near 5 μM. The similar dependence of gluconeogenesis and urea synthesis on oxygen concentration indicates that the two pathways have equal access to the cellular ATP supply, i.e., there is no evidence that either pathway is preferentially turned off to spare ATP for the other. The cellular energy state had an oxygen dependence similar to that of glucose and urea synthesis. It is suggested that the behavior of gluconeogenesis and urea production is a reflection of homeostatic regulation of cellular metabolism which is designed to respond to changes in [ATP]/[ADP][Pi].
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041200103
Permalink
