Insulin cyclic 3’,5’-adenosine monophosphate

J. M. Gunn, S. M. Tilghman, R. W. Hanson, L. Reshef, and F. J. Ballard, Effects of cyclic adenosine monophosphate, dexamethasone and insulin on phosphoenolpyruvate carboxykinase synthesis in Reuber H-35 hepatoma cells. Biochemistry 14 2350-2357 (1975). 

The promotion of the synthesis of lipids (lipogenesis) and the inhibition of the release of free fatty acids (lipolysis) by insulin also requires a complex network of signalling pathways, partially coupled to those for the Glut4 activation. In adipocytes, insulin inhibits lipolysis primarily through inhibition of a hormone-sensitive lipase via reduction of the amount of cyclic adenosine monophosphate (cAMP) present in the cells. In this specific action, a phosphodiesterase is involved, ] a level where again the phosphate antagonist vanadate can interfere. 

Aronica, S.M. and Katzenellenbogen, B.S. (1993) Stimulation of estrogen receptor-mediated transcription and alteration in the phosphorylation state of the rat uterine estrogen receptor by estrogen, cyclic adenosine monophosphate, and insulin-like growth factor-I. Molecular Endocrinology, 7, 743-752. 

Glucagon exerts its ejfects on cells by binding to a receptor on the cell surface, which stimulates the synthesis of the intracellular second messenger, cyclic adenosine monophosphate (cAMP) (Fig. 26.3). cAMP activates protein kinase A, which phosphorylates key regulatory enzymes, activating some and inhibiting others. Changes of cAMP levels also induce or repress the synthesis of a number of enzymes. Insulin promotes the dephosphorylation of these key enzymes. 

Phosphofructokinase 2 (PFK-2) is negatively regulated by phosphorylation in the liver (the enzyme that catalyzes the phosphorylation is the cyclic adenosine monophosphate [cAMP]-dependent protein kinase). However, in skeletal muscle, PFK-2 is not regulated by phosphorylation. This is because the skeletal muscle isozyme of PFK-2 lacks the regulatory serine residue, which is phosphorylated in the liver. However, the cardiac isozyme of PFK-2 is phosphorylated and activated by a kinase cascade initiated by insulin. This allows the heart to activate glycolysis and to use blood glucose when blood glucose levels are elevated. 

Jeppesen PB, Gregersen S, Poulsen CR, Hermansen K (2000) Stevioside acts directly on pancreatic (3 cells to secrete insulin actions independent of cyclic adenosine monophosphate and adenosine triphosphate-sensitive K-l—channel activity. Metabolism 49 208-214 Abudula R, Jeppesen PB, Rolfsen SED, Xiao J, Hermansen K (2004) Rebaudioside A potentially stimulates insulin secretion from isolated mouse islets studies on the dose-, glucose-, and calcium-dependency. Metabolism 53 1378-1381... 

Ohno T, Kato N, Ishii C, Shimizu M, Ito Y, Tomono S and Kawazu S. 1993. Genistein augments cyclic adenosine 3 5 -monophosphate(cAMP) accumulation and insulin release in MIN6 cells. Endocr Res 19(4) 273-285. 

Cyclic-3, 5 -adenosine monophosphate (CAMP) appears important in modulating insulin release56-58. CAMP itself stimulates the release of Insulin in vitro2 7,10. has also been shown that islet CAMP levels... 

Benjamin, W. B., and Singer, I., 1975, Actions of insulin, epinephrine, and dibutyryl cyclic adenosine 5 -monophosphate on fat cell protein phosphorylations. Cyclic adenosine 5 -monophosphate dependent and independent mechanisms. Biochemistry 14 3301. 

Manganiello, V., and Vaughan, M., 1973, An effect of insulin on cyclic adenosine 3, 5 -monophosphate phosphodiesterase activity in fat cells, J. Biol. Chem. 248 7164. 

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). 

---