Factors which influence cyclic AMP formation and degradation in an islet cell tumor of the Syrian hamster

TY - JOUR

T1 - Factors which influence cyclic AMP formation and degradation in an islet cell tumor of the Syrian hamster

AU - Rosen, Ora M.

AU - Hirsch, Allen H.

AU - Goren, Elihu N.

N1 - Funding Information: Cyclic 3’,5’-AMP (cyclic AMP) has been implicated as an intracellular mediator of insulin release in wivo (1) as well as in isolated islets of Langerhans (2), and in the perfused pancreas (3, 4). Recent studies suggest that it may function to modulate the release of insulin in response to glucose (5). The availability of an islet cell tumor (6) that secretes insulin in response to hypoglycemic agents of the sulfonylurea type (7) has enabled us to study cyclic AMP formation and degradation in pancreatic endocrine tissue without employing microdissection techniques. The insulinoma was found to possess adenyl cyclase activity which was stimulated by fluoride or glucagon,2 and cyclic nucleotide phosphodiesterase activity which was inhibited by theophylline and chlorpropamide.3 Porcine glucagon and insulin were kindly supplied by Dr. Mary Root, Eli Lilly & Co., secretin was obtained from Professor Jorpes, Karolinska Institutet, Stockholm, and chlorpropamide was from Pfizer Corp. Prostaglandin Ei was generously provided by Dr. John Pike, Upjohn Co. 14C-ATP (UL) was purchased from New England Nuclear Corp. The tumor line was maintained by subcutaneous inoculation into male Syrian (golden) hamsters (6). Approximat,ely 30 days after inoculation, loto 15-g tumors were removed and homogenized in 2 vol of 0.02 M Tris-HCl buffer, pH 7.5. The homogenate was centrifuged at 20,OOOg for 30 min and the pellet was stored in l-ml aliquots (lo-15 mg protein/ml) in liquid Ns . The material which sedimented at 20,OOOg was used as the source of 1 This is Communication No. 248 from the Joan and Lester Avnet Institute of Molecular Biology. Supported by grants from the National Institutes of Healt,h (AM 09038) and t,he American Cancer Society (ACS P489). 2 While this manuscript was in preparation, I. D. Goldfine, L. Birnbaumer, and J. Roth reported the presence of a glucagon-stimulated adenyl cyclase in a Syrian hamster insulinoma. (Abstracts of the 31st Annual Meeting of the American Diabetes Association, Diabetes 20, Suppl. 1, 341, 1971.) 3 We have also found that the tumor contains cyclic AMP-dependent protein kinase activity. Copyright: Copyright 2014 Elsevier B.V., All rights reserved.

PY - 1971/10

Y1 - 1971/10

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U2 - 10.1016/0003-9861(71)90175-5

DO - 10.1016/0003-9861(71)90175-5

M3 - Article

C2 - 4329857

AN - SCOPUS:0015138399

SN - 0003-9861

VL - 146

SP - 660

EP - 663

JO - Archives of Biochemistry and Biophysics

JF - Archives of Biochemistry and Biophysics

IS - 2

ER -