Effect of insulin on the pyruvate dehydrogenase complex in the rat brain
Rinaudo, M.T.; Curto, M.; Bruno, R.
Italian Journal of Biochemistry 34(4): 229-237
1985
ISSN/ISBN: 0021-2938 PMID: 3902717 Document Number: 263762
(1) The level of PDHa and PDHt is substantially reduced in the rat brain 24 hours after alloxan adminstration. Effects are almost completely reversed by insulin administration. (2) PDHa and PDHt from alloxan rat brains are remarkably activated when assayed on samples obtained by combining and preincubating at 30.degree. C for 30 min a homogenate from fresh unfrozen brains of alloxan rats, with a similarly treated preparation from fresh unfrozen brains of normal or insulin rats. On the contrary, no activation at all is obtained if the preincubation is carried out on homogenates from frozen and thawed brains. (3) In alloxan rats, brain acetyl CoA level decreases remarkably whereas plasma free fatty acid concentration increases. Such changes disappears after insulin administration. (4) The oxygen uptake, the respiratory control index and the ADP/O ratio in mitochondrial preparations obtained from brains of alloxan rats show no modifications at all.