Effects of adenosine derivatives on cAMP accumulation and lipolysis in rat adipocytes and on adenylate cyclase in adipocyte plasma membranes
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N6-monosubstituted adenosine (Ad)-derivatives and Ad-derivatives altered in the adenine-or ribose-moiety have been compared with Ad in their effects on noradrenaline (NA)-stimulated cAMP accumulation, on lipolysis stimulated by NA or theophylline (THEO) and on adenylate cyclase (AC) activity of adipocyte plasma membranes.
In isolated adipocytes about 0.01 μM Ad caused a 50% inhibition of cAMP accumulation stimulated maximally by 1μM NA. Depending upon the structure of substituent, the Ad-N6-derivatives were up to one order of magnitude either more or less active than Ad itself. 2-fluoro-Ad was nearly as active as Ad, whereas 2′,5′-dideoxy-Ad and 2′-deoxy-Ad were practically ineffective as inhibitors of NA-stimulated cAMP accumulation. All compounds showed the same order of potency relative to Ad, when tested against lipolysis stimulated maximally by 1 mM THEO or submaximally by 0.3 μM NA.
In adipocyte plasma membranes a 50% inhibition of AC activity stimulated by 10μM NA was observed at about 10 μM Ad. None of the N6-substituted derivatives had any effect on either basal or NA-stimulated AC activity, whereas 2′,5′-dideoxy-Ad proved to be about 40 times more potent than Ad. 2′-deoxy-Ad and 2-fluoro-Ad were nearly equipotent to Ad. Similar results were obtained, if AC was stimulated with 5′-guanylylimidodiphosphate or NaF. Neither the N6-derivatives nor THEO could reverse the inhibitory effect of Ad on AC in plasma membranes.
It is concluded, that different mechanisms are involved in the inhibitory effects of Ad on cAMP accumulation and lipolysis in intact cells and on AC activity of adipocyte plasma membranes.
Key wordsFat cell cAMP Lipolysis Adenosine derivatives Plasma membranes
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- Chen, R. F.: Removal of fatty acids from serum albumin by charcoal treatment. J. Biol. Chem. 242, 173–181 (1967)Google Scholar
- Clark, R. B., Seney, M. N.: Regulation of adenylate cyclase from cultured human cell lines by adenosine. J. Biol. Chem. 251, 4239–4246 (1976)Google Scholar
- Clark, R. B., Gross, R., Ying-Fu Su, Perkins, J. P.: Regulation of adenosine 3′,5′-monophosphate content in human astrocytoma cells by adenosine and the adenine nucleosides. J. Biol. Chem. 249, 5296–5303 (1974)Google Scholar
- Ebert, R., Schwabe, U.: Studies on the antilipolytic effect of adenosine and related compounds in isolated fat cells. Naunyn-Schmiedeberg's Arch. Pharmacol. 278, 247–259 (1973)Google Scholar
- Fain, J. N.: Inhibition of adenosine cyclic 3′,5′-monophosphate accumulation in fat cells by adenosine, N6-(phenylisopropyl) adenosine and related compounds. Mol. Pharmacol. 9, 595–604 (1973a)Google Scholar
- Fain, J. N.: Biochemical aspects of drug and hormone action on adipose tissue. Pharmacol. Rev. 25, 67–118 (1973b)Google Scholar
- Fain, J. N., Wieser, P. B.: Effects of adenosine deaminase on cyclic adenosine monophosphate accumulation, lipolysis, and glucose metabolism of fat cells. J. Biol. Chem. 250, 1027–1034 (1975)Google Scholar
- Fain, J. N., Pointer, R. H., Ward, W. F.: Effects of adenosine nucleosides on adenylate cyclase, phosphodiesterase, cyclic adenosine monophosphate accumulation and lipolysis in fat cells. J. Biol. Chem. 247, 6866–6872 (1972)Google Scholar
- Gilman, A. G.: A protein binding assay for adenosine-3′,5′-cyclic monophosphate. Proc. Nat. Acad. Sci. (U.S.A.) 67, 305–312 (1970)Google Scholar
- Haslam, R. J., Rosson, G. M.: Effects of adenosine on levels of adenosine cyclic 3′,5′-monophosphate in human blood platelets in relation to adenosine incorporation and platelet aggregation. Mol. Pharmacol. 11, 528–544 (1975)Google Scholar
- Huang, M., Daly, J. W.: Adenosine-elicited accumulation of cyclic AMP in brain slices: potentiation by agents which inhibit uptake of adenosine. Life Sci. 14, 489–503 (1974)Google Scholar
- Huang, M., Drummond, G. I.: Effect of adenosine on cyclic AMP accumulation in ventricular myocardium. Biochem. Pharmacol. 25, 2713–2719 (1976)Google Scholar
- Lambert, M., Neish, A. C.: Rapid method for estimation of glycerol in fermentation solutions. Can. J. Res., Sect. B 28, 83–89 (1950)Google Scholar
- Lowry, O. H., Rosebrough, N. J., Farr, A. L., Randall, R. J.: Protein measurement with the folin phenol reagent. J. Biol. Chem. 193, 265–275 (1951)Google Scholar
- McKeel, D. W., Jarett, L.: Preparation and characterization of a plasma membrane fraction from isolated fat cells. J. Cell. Biol. 44, 417–432 (1970)Google Scholar
- McKenzie, S. G., Baer, H. P.: On the mechanism of adenyl cyclase inhibition by adenosine. Can. J. Physiol. Pharmacol. 51, 190–196 (1973)Google Scholar
- Nash, T.: The colorimetric estimation of formaldehyde by means of the Hantzsch reaction. Biochem. J. 55, 416–421 (1953)Google Scholar
- Prilop, B.: Untersuchungen zur Hemmbarkeit des durch Adenosindesaminase an isolierten Adipocyten ausgelösten Anstiegs von cyclischem Adenosin-3′,5′-monophosphat und der Lipolyse durch Prostaglandin E1 und N6-Phenylisopropyladenosin. Doctoral Thesis, Medizinische Hochschule Hannover (1976)Google Scholar
- Rall, T. W., Sattin, A.: Factors influencing the accumulation of cyclic AMP in brain tissue. In: Advances in Biochemical Psychopharmacology (P. Greengard and E. Costa, eds.) Vol. 3, pp. 113–133. New York: Raven Press 1970Google Scholar
- Rodbell, M.: Metabolism of isolated fat cells: I. Effects of hormones on glucose metabolism and lipolysis. J. Biol. Chem. 239, 375–380 (1964)Google Scholar
- Rodbell, M., Londos, C.: Regulation of hepatic adenylate cyclase by glucagon, GTP, divalent cations, and adenosine. Metabolism 25, 1347–1349 (1976)Google Scholar
- Sattin, A., Rall, T. W.: The effect of adenosine and adenine nucleotides on the cyclic adenosine 3′,5′-phosphate content of guinea pig cerebral cortex slices. Mol. Pharmacol. 6, 13–23 (1970)Google Scholar
- Schwabe, U., Ebert, R., Erbler, H. C.: Adenosine release from isolated fat cells and its significance for the effects of hormones on cyclic 3′,5′-AMP levels and lipolysis. Naunyn-Schmiedeberg's Arch. Pharmacol. 276, 133–148 (1973)Google Scholar
- Schwabe, U., Ebert, R., Erbler, H. C.: Adenosine release from fat cells: effect on cyclic AMP levels and hormone actions. In: Advances in Cyclic Nucleotide Research (G. I. Drummond, P. Greengard, G. A. Robinson, eds.) Vol. 5, pp. 569–584. New York: Raven Press 1975Google Scholar
- Schwabe, U., Ebert, R., Schönhöfer, P. S.: Sensitive determination for adenylate cyclase activity by cyclic adenosine 3′,5′-monophosphate protein binding assay. Naunyn-Schmiedeberg's Arch. Pharmacol. 286, 83–96 (1974)Google Scholar
- Stock, K., Prilop, M.: Dissociation of catecholamine-induced formation of adenosine 3′,5′-monophosphate and release of glycerol in fat cells by prostaglandin E1, E2 and N6-phenylisopropyladenosine. Naunyn-Schmiedeberg's Arch. Pharmacol. 282, 15–31 (1974)Google Scholar
- Trost, T., Stock, K.: Effects of N6-substituted adenosine derivatives on noradrenaline (NA)-induced lipolysis and cAMP formation in rat adipocytes, and on NA-stimulated adenylate cyclase in adipocyte plasma membranes. Naunyn-Schmiedeberg's Arch. Pharmacol. 293, R31 (1976)Google Scholar
- Westermann, E., Stock, K.: Inhibitors of lipolysis: potency and mode of action of α- and β-adrenolytics, methoxamine dervatives, prostaglandin E1 and phenylisopropyladenosine. In: Adipose Tissue-Regulation and Metabolic Functions (B. Jeanrenaud and D. Hepp, eds.) pp. 47–54. Stuttgart: G. Thieme 1970Google Scholar
- Westermann, E., Stock, K., Bieck, P.: Phenylisopropyl-Adenosin (PIA): Ein potenter Hemmstoff der Lipolyse in vitro und in vivo. Fettstoffwechsel 5, 68–73 (1969)Google Scholar