Abstract
Pyruvate dehydrogenase complex (PDC) from rat kidney or pig heart previously inactivated by phosphorylation (PDHP) was activatedin vitro by PDHP phosphatase from kidneys of starved or fed rats. Starvation for 48 h of the rats from which the PDC was prepared led to a decrease in the rate of activation of PDC at early time periods (<2 min), particularly at submaximal concentrations of Mg2+. Using intact permeable kidney mitochondria incubated for 15 sec, it was found that starvation of rats more than doubled the Mg2+ concentration at which the half maximal increment of PDC activity (PDCa) was observed. Reduction of PDHP phosphatase activity due to starvation was also apparent when phosphatase was separated from PDC and recombined with PDC from the same or different animals.
Intraperitoneal injection of insulin and glucose 1 h before sacrifice of starved rats prevented the reduction of PDHP phosphatase activity whether or not protein synthesis was inhibited. The effect of insulin in restoration of PDHP phosphatase activity of starved rats was not mimicked by 5-methylpyrazole 3-carboxylic acid, an inhibitor of lipolysis.
When renal PDHP phosphatase was incubated with pig heart PDC in the presence of 10 mM Mg2+ and 0.1 mM Ca2+ the increment in PDCa, in 1 min was 30% of fully activated PDC activity (PDC1) observed after 15 min. Removal of divalent cations did not affect the increment in 1 min but prevented further increments. Conversely okadaic acid diminished 1 min increment but did not disturb PDCt. It is suggested that the different behaviour of renal PDC from fed and starved animals may partly be due to different divalent cation independent PDHP phosphatase activity.
Similar content being viewed by others
References
Linn TC, Pettit FH, Reed LJ: α-Keto acid dehydrogenase complexes, X. Regulation of the activity of the pyruvate dehydrogenase complex from beef kidney mitochondria by phosphorylation and dephosphorylation. Proc Natl Acad Sci USA 62: 234–41, 1969
Linn TC, Pettit FH, Hucho F, Reed LJ: α-Keto acid complexes, XI. Comparative studies of regulatory properties of the pyruvate dehydrogenase complexes from kidney, heart and liver mitochondria. Proc Natl Acad Sci USA 64: 227–34, 1969.
Pettit FH, Pelley JW, Reed Ll: Regulation of pyruvate dehydrogenase kinase and phosphatase by acetyl-CoA and NADH/NAD ratios. Biochem Biophys Res Comm 65: 575–82, 1975
Randle PJ: Fuel selection in animals. Biochem Soc Trans 14: 799–806, 1986
Baxter MA, Coore HG: The mode of regulation of pyruvate dehydrogenase of lactating rat mammary gland. Biochem J 174: 553–61, 1978
Sale GJ, Randle PJ: Occupancy of phosphorylation sites in pyruvate dehydrogenase phosphate complex in rat heartin vivo. Biochem J 206: 221–229, 1982
Baxter MA, Coore HG: Reduction of mitochondrial pyruvate dehydrogenase phosphatase activity in lactating rat mammary gland following starvation or insulin deprivation. Biophys Res Commun 87: 433–40, 1979
Baxter MA: The regulation, by phosphorylation, of the pyruvate dehydrogenase complex in lactating rat mammary gland [dissertation]. Birmingham, England: University of Birmingham, 1979
Cooper RH, Randle PH, Denton RM: Regulation of heart muscle pyruvate dehydrogenase kinase. Biochem J 143: 625–41, 1974
Coore HG, Denton RM, Martin BR, Randle PJ: Regulation of adipose tissue pyruvate dehydrogenase by insulin and other hormones. Biochem J 125: 115–27, 1971
Martin MT, Shapiro R: Atomic absorption spectrometry of magnesium. Methods Enzymol 158: 365–70, 1988
Thomas AP, Denton RM: Use of toluene-permeabilized mitochondria to study the regulation of adipose tissue pyruvate dehydrogenasein situ. Biochem J 238: 93–101, 1986
Garland PB, Randle PJ: A rapid enzymatic assay for glycerol. Nature 196: 987–8, 1962
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ: Protein Measurement with the Folin Phenol Reagent. J Biol Chem 193: 265–75, 1951
Whitehouse S, Cooper RH, Randle PJ: Mechanism of activation of pyruvate dehydrogenase by dichloracetate and other halogenated carboxylic acids. Biochem J 141: 761–74, 1974
Denton RM, Midgley PJW, Rutter GA, Thomas AP, McCormac JG: Studies into the mechanism whereby insulin activates pyruvate dehydrogenase complex in adipose tissue. Ann NY Acad Sci 573: 285–96, 1989
Haystead TAJ, Sim ATR, Carling D, Honnor RC, Tsukitani Y, Cohen P, Hardie DG: Effects of the tumour promoter okadaic acid on intracellular protein phosphorylation and metabolism. Nature 337: 78–81, 1989
Cohen P, Holmes CFB, Tsukitani Y: Okadaic acid: a new probe for the study of cellular regulation. TIBS 15: 98–102, 1990
Rothblum LI, Devlin TM, Ch'ih JJ: Regulation of mammalian protein synthesisin vitro. Biochem J 156: 151–7, 1976
Holness MJ, Sugden MC: Regulation of renal and hepatic pyruvate dehydrogenase complex on carbohydrate refeeding after starvation. Biochem J 241: 421–5, 1987
Cohen P, Cohen PTW: Protein phosphatases come of age. J Biol Chem 264: 21435–8, 1989
Stansbie D, Denton RM, Bridges BJ, Pask HT, Randle, PJ: Regulation of pyruvate dehydrogenase phosphate phosphatase activity in rat epididymal fat pads. Biochem J 154: 225–236, 1976
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cockburn, B.N., Coore, H.G. Starvation reduces pyruvate dehydrogenase phosphate phosphatase activity in rat kidney. Mol Cell Biochem 149, 131–136 (1995). https://doi.org/10.1007/BF01076571
Issue Date:
DOI: https://doi.org/10.1007/BF01076571