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Insulin phosphodiesterase

Increased lipid synthesis/inhibi-tion of lipolysis Activation of lipoprotein lipase (LPL)/induc-tion of fatty acid synthase (FAS)/inactivation of hormone sensitive lipase (HSL) Facilitated uptake of fatty acids by LPL-dependent hydrolysis of triacylglycerol from circulating lipoproteins. Increased lipid synthesis through Akt-mediated FAS-expression. Inhibition of lipolysis by preventing cAMP-dependent activation of HSL (insulin-dependent activation of phosphodiesterases )... [Pg.634]

Cyclic AMP (cAMP) (Figure 18-5) is formed from ATP by adenylyl cyclase at the inner surface of cell membranes and acts as an intracellular second messenger in response to hormones such as epinephrine, norepinephrine, and glucagon. cAMP is hydrolyzed by phosphodiesterase, so terminating hormone action. In hver, insulin increases the activity of phosphodiesterase. [Pg.147]

In adipose tissue, insulin stimulation suppresses triglyceride hydrolysis (to free fatty acids and glycerol) by activating cAMP phosphodiesterase (cAMP PDE). Cyclic AMP, (3, 5 cAMP), is required to stimulate hormone sensitive lipase (HSL), the enzyme which hydrolyses triglyceride within adipocytes PDE converts active 3, 5 cAMP to inactive 5 AMP thus preventing the stimulation of HSL. The net effect of insulin on lipid metabolism is to promote storage. [Pg.118]

Glucagon stimulates adenylate cyclase activity and this increases the concentration of cyclic AMP. Insulin antagonises this effect via an increase in the activity of cyclic AMP phosphodiesterase, which hydrolyses cyclic AMP to AMP, which results in a decrease in the concentration of cyclic AMP (Figure 6.34). [Pg.123]

Figure 6.34 Effects of glucagon and insulin on the cyclic AMP level. Glucagon increases the activity of adenylate cyclase, which increases the concentration of cyclic AMP whereas insulin activates the phosphodiesterase which hydrolyses cyclic AMP to form AMP. Cyclic AMP activates protein kinase A. Figure 6.34 Effects of glucagon and insulin on the cyclic AMP level. Glucagon increases the activity of adenylate cyclase, which increases the concentration of cyclic AMP whereas insulin activates the phosphodiesterase which hydrolyses cyclic AMP to form AMP. Cyclic AMP activates protein kinase A.
In contrast to glucagon, the peptide hormone insulin (see p. 76) increases glycogen synthesis and inhibits glycogen breakdown. Via several intermediates, it inhibits protein kinase GSK-3 (bottom right for details, see p. 388) and thereby prevents inactivation of glycogen synthase. In addition, insulin reduces the cAMP level by activating cAMP phosphodiesterase (PDE). [Pg.120]

Metabolism. The nucleotide cAMP (adenosine 3, 5 -cyclic monophosphate) is synthesized by membrane-bound adenylate cyclases [1] on the inside of the plasma membrane. The adenylate cyclases are a family of enzymes that cyclize ATP to cAMP by cleaving diphosphate (PPi). The degradation of cAMP to AMP is catalyzed by phosphodiesterases [2], which are inhibited by methylxanthines such as caffeine, for example. By contrast, insulin activates the esterase and thereby reduces the cAMP level (see p. 388). [Pg.386]

A. R. Saltiel, J. A. Fox, P. SherUne, P. Cuatrecasas (1986). Insulin-stimulated hydrolysis of a novel glycoUpid generates modulators of cAMP phosphodiesterase. Science 233 967-972. P. R. Shepherd, B. B. Kahn (1999). Glucose transporters and insulin action—implications for insulin resistance and diabetes melUtns. N. Eng. J. Med. 341 248. [Pg.384]

Tolbutamide, N-[(butylamino)carbonyl]-4-methylbenzenesulphona-mide N-(butylamino) carbonyl-p-toluene sulphonamide is a sulphonlylurea that is orally active as a hypoglycemic agent. The drug stimulates the poncreatic islet beta cells to release extra insulin. It also inhibits phosphodiesterase, which preserves cyclic AMP and thus favor glycogenolysis in a number of tissues. [Pg.720]

Other evidence for the involvement of a G-protein in the action of insulin has come from studies by Walaas and co-workers [104]. They have demonstrated that insulin stimulated the activity of a cyclic AMP-dependent protein kinase activity in sarcolemma membranes. As this effect of insulin was enhanced if micromolar concentrations of GTP-binding protein were present, they suggested that a guanine nucleotide regulatory protein was involved in the hormonal control of this kinase. Indeed, cholera toxin also appeared to obliterate this action of insulin, as it did the effect of insulin on liver adenylate cyclase and the peripheral plasma membrane cyclic AMP phosphodiesterase in liver. [Pg.339]

Similar to other tissues, insulin-producing cells possess an adenylate cyclase-cAMP system including stimulatory and inhibitory G-proteins and phosphodiesterases. [Pg.92]

Adenylate Cyclase System. In the presence of sulphonylureas some increase in cAMP has been observed to occur in islet tissue. This effect seems, however, not to be of relevance for insulin secretion (Gylfe et al., 1984) because it is small (Taljedal, 1982). The effect on cAMP is probably due to Ca2+ influx (Malaisse and Malaisse-Lagae, 1984). Another possibility comes from the observation that sulphonylureas inhibit low-Km phosphodiesterase (Malaisse and Malaisse-Lagae, 1984). [Pg.114]

As discussed above (see chapter 6, section 4.1), initiation of insulin secretion via depolarization can be modulated by compounds that affect the adenylate cyclase system. It is therefore not surprising that glucagon and db-cAMP potentiate tolbutamide-induced insulin secretion (Ammon, 1975). This also holds for methylxanthines which, at the concentrations used in vitro, inhibit phosphodiesterase and thus cAMP (Lambert et al., 1971 Ammon, 1975). [Pg.114]

Muller, G., Grey, S., Jung, C., and Bandlow, W. Insulin-like signaling in yeast modulation of protein phosphatase 2A, protein kinase A, cAMP-specific phosphodiesterase, and glycosyl-phospha-tidylinositol-specific phospholipase C activities. Biochemistry, 2000, 39, 1475-1488. [Pg.113]

T. Rahn, L. Ronnstrand, C. Wern-STEDT, M.-J. Leroy, H. Tornqvist, V. Manganiello, P. Belerage, and E. De-GERMAN, Identification of the site in the cGMP-inhibited phosphodiesterase phosphorylated in adipocytes in response to insulin and isoproterenol, J. Biol. Chem., 1996, 277, 11575-11580. [Pg.316]

E. Degerman, M.-J. Leroy, M. Taira, P Belfrage, and V. Manganiello, A role for insulin-mediated regulation of cyclic monophosphate (cGMP)-inhibited phosphodiesterase in the antilipolytic action of insulin. In D. Le Roith, J. M. OleF.sky, and S. Taylor, (ed) Diabetes Mellitus A Fundamental and Clinical Text, Lippincott-Raven, Philadelphia, 1996, pp. 197-204. [Pg.320]

M.L. Elks and V.C. Manganiello, Antilipolytic action of insulin role of cAMP phosphodiesterase activation. Endocrinology, 1985, 116, 2119-2221. [Pg.320]

H. Eriksson and H. Tornqvist, Specific inhibition of the cGMP-inhibited cAMP phosphodiesterase blocks the insulin-like antilipolytic effect of growth hormone in rat adipocytes. Mol. Cell. Biochem., 1997, 169, 37-42. [Pg.320]

E. Hagstrom-Toft, J. Bounder, S. Eriksson, and P. Arner, Role of phosphodiesterase 111 in the antilipolytic effect of insulin in vivo. Diabetes, 1995, 44, 1170-1175. [Pg.321]

S. Enoksson, E. Degerman, E. Hagstrom-Toft, V. Large, and P. Arner, Various phosphodiesterase subtypes mediate the in vivo antilipolytic effect of insulin on adipose tissue and skeletal muscle in man, Diabetologia, 1998, 41, 560-568. [Pg.321]

E. Degerman, C.J. Smith, H. Tornqvist, V. Vasta, V. Manganiello, and P. Belfrage, Evidence that insulin and iso-prenaline activate the cGMP-inhibited low-Km cAMP phosphodiesterase in rat fat cells by phosphorylation, Proc. Natl. Acad. Sci. USA, 1990, 87, 533-537. [Pg.321]

C.J. Smith, V. Vasta, E. Degerman, P. Belfrage, and V. Manganiello, Hormone-sensitive cyclic GMP-inhibited cyclic AMP phosphodiesterase in rat adipocytes. Regulation of insulin- and cAMP-dependent activation by phosphorylation, J. Biol. Chem., 1991, 266, 13385-13390. [Pg.321]

T. Rahn, M. Ridderstrale, H. Tornqvist, V. Manganiello, G. Fredrikson, P. Belfrage, and E. Degerman, Essential role of phosphatidylinositol 3-kinase in insulin-induced activation and phosphorylation of the cGMP-inhibited cAMP phosphodiesterase in rat adipocytes studies using the selective inhibitor wortmannin, FEBS Lett., 1994, 350, 314-317. [Pg.321]


See other pages where Insulin phosphodiesterase is mentioned: [Pg.818]    [Pg.215]    [Pg.466]    [Pg.305]    [Pg.214]    [Pg.571]    [Pg.584]    [Pg.197]    [Pg.327]    [Pg.338]    [Pg.338]    [Pg.338]    [Pg.339]    [Pg.340]    [Pg.341]    [Pg.329]    [Pg.329]    [Pg.166]    [Pg.571]    [Pg.15]    [Pg.83]    [Pg.189]    [Pg.272]    [Pg.231]    [Pg.321]   
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