Activation of rat adipocyte plasma membrane adenylate cyclase by sodium azide

Rahmanian, Masoud; Jarett, Leonard

doi:10.1016/0006-291x(74)90261-7

Cited by 15 publications

(3 citation statements)

References 10 publications

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“…Azide, which has recently been introduced as a stimulant of adenylate cyclase [11 ], gives rise to an activity, which is inhibited by atebrine (table 5). This is a further evidence for a difference in stimulation mechanism between azide and fluoride.…”

Section: Methodsmentioning

confidence: 99%

Effects of reducing and oxidizing agents on the adenylate cyclase activity in adipocyte plasma membranes

Löw

Werner

1976

FEBS Letters

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Section: Methodsmentioning

confidence: 99%

Effects of reducing and oxidizing agents on the adenylate cyclase activity in adipocyte plasma membranes

Löw

Werner

1976

FEBS Letters

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“…In this regard we have therefore investigated the effect of various salts which appear to be activators of some mammalian hormonesensitive adenylate cyclase systems [2,3].…”

Section: Introductionmentioning

confidence: 99%

Activation of guanylate cyclase by sodium azide in rat adipocytes

et al. 1976

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“…Fluoride anion, a powerful activator ofenzyme activity, also appears to affect adenylate cyclase at the regulatory subunit, but it is as yet uncertain whether activation by fluoride requires interaction ofguanine nucleotides with the regulatory subunit (5,6). Recently inorganic salts ofnon-fluoride anions have been shown to stimulate adenylate cyclase activity in several tissues (7)(8)(9)(10)(11)(12)(13). Although studies of liver, kidney, and pancreas preparations (9)(10)(11) have shown that inorganic salts enhance activation of adenylate cyclase by the synthetic GTP analog 5'-guanylyl imidodiphosphate (GMP-P[NH]P), the mechanism of enzyme activation by salts, and specifically the interaction ofions with the naturally occurring stimulatory nucleotide GTP, remains speculative (14).…”

mentioning

confidence: 99%

Salts promote activation of fat cell adenylate cyclase by GTP: special role for sodium ion.

Katz¹,

Partilla²,

Piñeyro³

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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The effects of GTP on adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of human and rat fat cell membranes ("ghosts" and purified membranes) were examined in the absence and presence of added inorganic salts. With human ghosts GTP alone (0.1 mM) inhibited enzyme activity by 40% at 30°C and had no significant effect at 3rC. At both temperatures Na' salts of Cl1, N3-, and S042-stimulated activity (up to 4-fold basal activity for 200 mM NaN3), with maximal effects at salt concentrations of 100-200 mM. Over the same concentration range these salts also allowed temperature-dependent stimulation by GTP. GTP increased the maximal activity produced by salt alone by about 2-fold at 30°C and about 4-fold at 37C. Na+ (added as Cl-) was much more effective than other alkali metal cations in promoting activation by GTP. Na+ salts allowed activation of the human enzyme by the GTP analog 5'-guanylyl imidodiphosphate and also promoted stimulation of rat fat cell adenylate cyclase by both nucleotides. In time course studies of human and rat fat cell ghosts, GTP appeared to sustain an initial high rate of salt-stimulated activity, which in the absence of nucleotide subsequently fell to a lower rate, suggesting that salts might activate adenylate cyclase by promoting the stimulatory effect of endogenous membrane-bound GTP. However, with purified human fat cell membranes and a GTP-free system, salts were still stimulatory and promoted activation by added GTP. These results differ from those of previous reports in other systems in which Na+ has promoted only inhibitory effects in GTP regulation of adenylate cyclase.Guanine nucleotides regulate the activity of mammalian adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1]. Activation of the enzyme by a number of agents, notably hormones and cholera toxin, has been suggested to occur by one or more mechanisms that facilitate an activating effect of GTP at the nucleotide regulatory subunit of the enzyme (1-4). Fluoride anion, a powerful activator ofenzyme activity, also appears to affect adenylate cyclase at the regulatory subunit, but it is as yet uncertain whether activation by fluoride requires interaction ofguanine nucleotides with the regulatory subunit (5, 6). Recently inorganic salts ofnon-fluoride anions have been shown to stimulate adenylate cyclase activity in several tissues (7-13). Although studies of liver, kidney, and pancreas preparations (9-11) have shown that inorganic salts enhance activation of adenylate cyclase by the synthetic GTP analog 5'-guanylyl imidodiphosphate (GMP-P[NH]P), the mechanism of enzyme activation by salts, and specifically the interaction ofions with the naturally occurring stimulatory nucleotide GTP, remains speculative (14).In our own studies of human and rat fat cell membranes ("ghosts"), we have found that a number of non-fluoride inorganic salts stimulate fat cell adenylate cyclase activity. Moreover, fat cell ghosts have proven to be a convenient system in which to study salt interaction with GTP. G...

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Activation of rat adipocyte plasma membrane adenylate cyclase by sodium azide

Cited by 15 publications

References 10 publications

Effects of reducing and oxidizing agents on the adenylate cyclase activity in adipocyte plasma membranes

Effects of reducing and oxidizing agents on the adenylate cyclase activity in adipocyte plasma membranes

Activation of guanylate cyclase by sodium azide in rat adipocytes

Salts promote activation of fat cell adenylate cyclase by GTP: special role for sodium ion.

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