ISSN:
1573-4919
Schlagwort(e):
adrenal medulla
;
chromaffin cells
;
glycolytic isoenzymes
;
glucose utilization
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Chemie und Pharmazie
,
Medizin
Notizen:
Abstract Glucose utilization by different metabolic pathways in bovine adrenal medulla has been studied using freshly isolated adrenal chromaffin cells. The rate of net glucose utilization in resting cells was 10.5 μmoles × g−1 × h−1 50% was transformed into lactate and pyruvate, the lactate to pyruvate ratio ranging from 3 to 7. 27% was metabolized through the tricarboxylic acid cycle and 3.1% was oxidized in the pentose phosphate pathway. The ratio of 14CO2 production from 11-14Cl glucose and 16-14Cl glucose was close to 2 at one hour of incubation. 3.210 of total glucose consumed was used in protein synthesis, and 1% was incorporated into lipids. Oxygen utilization in respiration by isolated adrenal chromaffin cells was 18.2 μmoles × g−1 × h−1, corresponding to 3.1 μmoles glucose × g−1 × h−1 or about 30°10 of total glucose consumed. The activities of hexokinase, enolase, pyruvate kinase, lactate dehydrogenase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were assayed in extracts of bovine adrenal medulla, being 1.0, 23, 40, 37, 6.0 and 3.0 U/g respectively. Hexokinase activity was identified as belonging mainly to isoenzyme I, with some isoenzyme II. Enolase was predominantly the αγ hybrid. Pyruvate kinase activity corresponded to a mixture of isoenzymes K and M. Lactate dehydrogenase activity corresponded to isoenzymes 1, 2 and 3, with smaller proportions of isoenzymes 4 and 5. Results are discussed mainly with respect to those reported for the brain.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00233804
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