Abstract

The long term objective of my research is to elucidate the mechanism of insulin actions at the molecular level.
The specific aims of the proposed studies are:
(Aim 1) to substantiate further the translocation hypothesis of insulin action on glucose transport, (Aim 2) to characterize the action of insulin on the K/m value of hexose transport, (Aim 3) to determine why certain characteristics of glucose transport in muscle are different from those in adipocytes, (Aim 4) to explore the possible mechanisms of insulin actions in muscle and adipocytes, and (Aim 5) to elucidate the mechanisms of insulin action of cAMP phosphodiesterase. To achieve Aim I, I will (a) track the movement of labeled glucose transporter in isolated rat epididymal and perirenal adipocytes, (b) study the effects of insulin on the V/max values for the transport of several sugar isomersin adipocytes, and (c) reevaluate the data that are apparently in disagreement with the translocation hypothesis. To achieve Aim 2, I will (a) reexamine the K/m value of glucose transport in the reconstitute liposome system, (b) characterize the insulin effect of the K/m value of hexose transport in adipocytes, and (c) to examine whether insulin changes the K/m value of glucose transport in hepatocytes. To achieve Aim 3, I will study how the V/max and K/m values of glucose transport in freshly isolated cardiac myocytes are affected by TPA (a phorbal ester), insulin, anoxia, and the agents that mimic the action of insulin in adipocytes. To achieve Aim 4, I will (a) study the effect of a low concentration of Ca2+ using A- 23187 and Quin 2/AM in two separate experiments, and (b) examine the relative effects of Mn2+ on the receptor kinase and glucose transport activities. To achieve Aim 5, I will study (a) factors involved in the stimulation of phosphodiesterase in the cell, (b) the reversal of insulin effect on phosphodiesterase, and (c) attempt to activate the enzyme in a cell-free system with cAMP-dependent protein kinase.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK019925-15
Application #
2137402
Study Section
Metabolism Study Section (MET)
Project Start
1977-04-01
Project End
1996-08-31
Budget Start
1991-09-01
Budget End
1996-08-31
Support Year
15
Fiscal Year
1991
Total Cost
Indirect Cost

  Institution

Name
Vanderbilt University Medical Center
Department
Physiology
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212

  Publications

Seo, S B; McNamara, P; Heo, S et al. (2001) Regulation of histone acetylation and transcription by INHAT, a human cellular complex containing the set oncoprotein. Cell 104:119-30
Printz, R L; Osawa, H; Ardehali, H et al. (1997) Hexokinase II gene: structure, regulation and promoter organization. Biochem Soc Trans 25:107-12
Ardehali, H; Yano, Y; Printz, R L et al. (1996) Functional organization of mammalian hexokinase II. Retention of catalytic and regulatory functions in both the NH2- and COOH-terminal halves. J Biol Chem 271:1849-52
Makino, H; Manganiello, V C; Kono, T (1994) Roles of ATP in insulin actions. Annu Rev Physiol 56:273-95
Yano, Y; Sumida, Y; Benzing, C F et al. (1993) Primary sites of actions of staurosporine and H-7 in the cascade of insulin action to glucose transport in rat adipocytes. Biochim Biophys Acta 1176:327-32
Yano, Y; May, J M (1993) Ligand-induced conformational changes modify proteolytic cleavage of the adipocyte insulin-sensitive glucose transporter. Biochem J 295 ( Pt 1):183-8
Goto, Y; Sumida, Y; Flanagan, J E et al. (1992) Effects of fluorescein isothiocyanate on insulin actions in rat adipocytes. Arch Biochem Biophys 293:224-30
Shibata, H; Robinson, F W; Soderling, T R et al. (1991) Effects of okadaic acid on insulin-sensitive cAMP phosphodiesterase in rat adipocytes. Evidence that insulin may stimulate the enzyme by phosphorylation. J Biol Chem 266:17948-53
Shibata, H; Robinson, F W; Benzing, C F et al. (1991) Evidence that protein kinase C may not be involved in the insulin action on cAMP phosphodiesterase: studies with electroporated rat adipocytes that were highly responsive to insulin. Arch Biochem Biophys 285:97-104
Shibata, H; Kono, T (1990) Cell-free stimulation of the insulin-sensitive cAMP phosphodiesterase by the joint actions of ATP and the soluble fraction from insulin-treated rat liver. Biochem Biophys Res Commun 170:533-9

Showing the most recent 10 out of 13 publications