Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Smooth muscle adenylate cyclase of a membrane preparation of canine gastric antrum has been characterized, and the effect of hormonal and neuronal agents examined. The enzyme is active in the presence of Mg2+ or Mn2+, but is inhibited by Ca2+. The Km is 0.5 mM ATP, similar to the Km of skeletal muscle adenylate cyclase. The enzyme is activated by isoproterenol but not norepinephrine, consistent with a beta 2-catecholamine receptor-adenylate cyclase interaction. Secretin activates the enzyme in concentrations as low as 1 . 10(-11) M, while glucagon was effective only at 1 . 10(-6) M. Prostaglandin E1 and E2 have a biphasic effect with activation of adenylate cyclase at 1 . 10(-5) M and a small but significant inhibition of enzyme activity at 1 . 10(-11) M.
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PMID:Effect of hormonal and neuronal agents on adenylate cyclase from smooth muscle of the gastric antrum. 45 75

Since glycogen accumulates in the placenta in diabetes and does not appear to be susceptible, in general, to the effect of fasting, the capacity of catecholamines to elicit glycogenolysis was investigated in non-diabetic and diabetic rats. Injection of epinephrine or isoproterenol caused a decrease in placental glycogen within 20 min in non-diabetic, 20 day pregnant rats, in association with the rise in serum glucose and lactate. Incubation with isoproterenol induced glycogenolysis in placental slices from non-diabetic and diabetic rats, nearly commensurate with lactate production. This effect of isoproterenol was concentration dependent and of similar magnitude in non-diabetic and diabetic rat placentas. Glucagon was ineffective in inducing placental glycogenolysis in vivo or in vitro. Protracted stimulation of the catecholamine receptor by the administration of cholera toxin effected a pronounced decrease in placental glycogen, percentagewise higher in diabetic than non-diabetic rats. These results show that placental glycogen is amenable to mobilization by hormonal stimuli effecting phosphorylase activation.
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PMID:Mobilization of placental glycogen in diabetic rats. 214 54

5'-Guanylylimidodiphosphate (Gpp(NH)-p) stimulates adenylate cyclase [ATP-pyrophosphate-lyase (cyclizing), EC 4.6.1.1] activity in plasma membranes isolated from frog and salmon erythrocytes, from rat adrenal, hepatic, and fat cells, and from bovine thyroid cells. The nucleotide acts cooperatively with the various hormones (glucagon, secretin, ACTH, thyrotropin, and catecholamines) that stimulate these adenylate cyclase systems with resultant activities that equal or exceed those obtained with hormone plus GTP or with fluoride ion. In the absence of hormones, Gpp(NH)p is a considerably more effective activator than GTP, and, under certain conditions of incubation, stimulates rat fat cell adenylate cyclase to levels of activity (about 20 nmoles of 3',5'-adenosine monophosphate mg protein per min) far higher than reported hitherto for any adenylate cyclase system examined. The nucleotide activates frog erythrocyte adenylate cyclase when the catecholamine receptor is blocked by the competitive antagonist, propranolol, and activates the enzyme from an adrenal tumor cell line which lacks functional ACTH receptors. In contrast, Gpp(NH)p does not stimulate adenylate cyclase in extracts from Escherichia coli B. Gpp(NH)p appears to be a useful probe for investigating the mechanism of hormone and nucleotide action on adenylate cyclase systems in eukaryotic cells.
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PMID:5'-Guanylylimidodiphosphate, a potent activator of adenylate cyclase systems in eukaryotic cells. 460 68

Basic and stimulated intracellular cAMP concentrations were measured in normal chicken liver and MC-29-virus-derived transplantable hepatoma (VTH) slices after in vitro incubation. Data indicated the preservation of catecholamine receptor but a loss of glucagon receptor in VTH. Comparing the relative stimulatory action of various catecholamines on cAMP concentration it was concluded that as in normal liver a predominantly beta 2-adrenergic receptor exists in the VTH, but its response to adrenaline is greater. Vinca alkaloids induced higher cAMP concentration in VTH than in normal liver. This stimulation was abolished by glucagon, while catecholamines and Vincristine acted in a synergistic manner on cAMP concentration.
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PMID:Further studies on the biochemical characterization of the MC-29 virus derived transplantable hepatoma (VTH). II. Modification of cyclic adenosine-3',5'-monophosphate levels by catecholamines, glucagon and Vinca alkaloids in normal chicken liver and VTH. 609 66