The effect of insulin supplementation on diabetes-induced alterations in the extractable levels of functional mitochondrial anion transport proteins.
The effect of insulin supplementation on diabetes-induced alterations in the levels of functional mitochondrial anion transport proteins has been determined. The experimental approach consisted of the extraction of the pyruvate, dicarboxylate, and citrate transport proteins from the mitochondrial inner membrane with Triton X-114 using rat liver mitoplasts (prepared from control, diabetic, or insulin-supplemented diabetic animals) as the starting material, followed by the reconstitution of the function of each transporter in a proteoliposomal system. This experimental strategy permitted the quantification of the functional levels of these three transporters in the absence of the complications that arise when such measurements are carried out with intact mitochondria (or mitoplasts). We found that treatment of diabetic rats (i.e., animals that were injected with streptozotocin 3 weeks earlier) on a daily basis with insulin for 3 weeks resulted in a reversal of the diabetes-induced (a) increase in the extractable and reconstitutable total (and specific) transport activities of the pyruvate and dicarboxylate transporters and (b) decrease in the activity of the citrate transporter. These findings indicate that diabetes-induced alterations in the functional levels of mitochondrial anion transport proteins are a direct consequence of the insulin insufficiency that characterizes this disease. Furthermore, this study provides the first demonstration that insulin participates in the regulation of the functional levels of liver mitochondrial anion transport proteins.
Kaplan
R S
RS
Department of Pharmacology, College of Medicine, University of South Alabama, Mobile 36688.
Mayor
J A
JA
Blackwell
R
R
Maughon
R H
RH
Wilson
G L
GL
D000818:Animals; D027321:Anion Transport Proteins; D001786:Blood Glucose / Q000378:metabolism; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism*; D029382:Dicarboxylic Acid Transporters; D007328:Insulin / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D026901:Membrane Transport Proteins; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D024101:Mitochondrial Proteins; D027501:Monocarboxylic Acid Transporters; D051381:Rats; D011919:Rats, Inbred Strains; D000070590:Solute Carrier Proteins; D015430:Weight Gain / Q000187:drug effects
D027321:Anion Transport Proteins; D001786:Blood Glucose; D002352:Carrier Proteins; D029382:Dicarboxylic Acid Transporters; D007328:Insulin; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D027501:Monocarboxylic Acid Transporters; C000629174:Mpc1 protein, rat; D000070590:Solute Carrier Proteins; C020723:citrate-binding transport protein