scholarly journals Modification of adenylate cyclase activity in LM cells by manipulation of the membrane phospholipid composition in vivo.

1976 ◽  
Vol 73 (12) ◽  
pp. 4482-4486 ◽  
Author(s):  
V. H. Engelhard ◽  
J. D. Esko ◽  
D. R. Storm ◽  
M. Glaser
Keyword(s):  
Adenylate Cyclase ◽  
Phospholipid Composition ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Membrane Phospholipid

scholarly journals Lysophosphatidylcholines can modulate the activity of the glucagon-stimulated adenylate cyclase from rat liver plasma membranes

1979 ◽  
Vol 178 (1) ◽  
pp. 217-221 ◽  
Author(s):  
M D Houslay ◽  
R W Palmer
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes ◽  
Increased Sensitivity

1. Synthetic lysophosphatidylcholines inhibit the glucagon-stimulated adenylate cyclase activity of rat liver plasma membranes at concentrations two to five times lower than those needed to inhibit the fluoride-stimulated activity. 2. Specific 125I-labelled glucagon binding to hormone receptors is inhibited at concentrations similar to those inhibiting the fluoride-stimulated activity. 3. At concentrations of lysophosphatidylcholines immediately below those causing inhibition, an activation of adenylate cyclase activity or hormone binding was observed. 4 These effects are essentially reversible. 5. We conclude that the increased sensitivity of glucagon-stimulated adenylate cyclase to inhibition may be due to the lysophosphatidylcholines interfering with the physical coupling between the hormone receptor and catalytic unit of adenylate cyclase. 6. We suggest that, in vivo, it is possible that lysophosphatidylcholines may modulate the activity of adenylate cyclase only when it is in the hormone-stimulated state.

Effects of benzyl alcohol on PTH receptor-adenylate cyclase system of canine kidney

1985 ◽  
Vol 248 (1) ◽  
pp. E31-E35
Author(s):  
K. J. Martin ◽  
C. L. McConkey ◽  
T. J. Stokes
Keyword(s):  
Enzyme Activity ◽  
Adenylate Cyclase ◽  
Benzyl Alcohol ◽  
Membrane Fluidity ◽  
Phospholipid Composition ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Adenylate Cyclase System ◽  
Hormone Sensitive ◽  
Canine Kidney

In many systems, perturbations of membrane architecture by changes of lipid and phospholipid composition have been shown to alter the activity of membrane-bound enzymes. The present studies examined the effect of benzyl alcohol, an agent that has been shown to increase membrane fluidity, on the parathyroid hormone (PTH)-sensitive adenylate cyclase system of canine kidney. Benzyl alcohol progressively increased basal adenylate cyclase activity up to fourfold and maximal enzyme activity in the presence of PTH, GTP, guanylimidodiphosphate, and sodium fluoride by four- to sixfold. In the presence of 20 mM Mn2+ (no Mg2+), conditions under which enzyme activity is devoid of influence of guanine nucleotides or hormones, benzyl alcohol was without effect. PTH binding was increased by 25% in the presence of benzyl alcohol without a change in binding affinity. Fluorescent polarization studies using diphenylhexatriene showed a decrease in fluorescence anisotropy in the presence of benzyl alcohol. The results suggest that benzyl alcohol facilitates the interaction of the components of the adenylate cyclase system, presumably by increasing membrane fluidity. Alterations of membrane fluidity may be a potent means of regulating hormone sensitive adenylate cyclase activity.

Protease effects on adenylate cyclase in potassium-depleted rabbit kidney

1988 ◽  
Vol 255 (5) ◽  
pp. F1033-F1039
Author(s):  
K. H. Raymond ◽  
S. D. Holland ◽  
T. K. Hymer ◽  
T. D. McKinney ◽  
M. S. Katz
Keyword(s):  
Adenylate Cyclase ◽  
Proteolytic Enzymes ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Rabbit Kidney ◽  
Potassium Depletion ◽  
Collecting Tubules ◽  
And Control

Potassium depletion in rabbits induces a renal concentrating defect in vivo and decreased hydrosmotic response to arginine vasopressin (AVP) in isolated cortical collecting tubules (CCT) perfused in vitro. The molecular basis of the AVP resistance in potassium depletion was investigated by comparing AVP-responsive adenylate cyclase activities in CCT from potassium-depleted and control rabbits. Vasopressin-responsive enzyme activity was impaired in CCT dissected from kidneys of potassium-depleted rabbits but not when kidneys were treated with collagenase to improve microdissection conditions. Potassium depletion also depressed parathyroid hormone (PTH)-stimulated adenylate cyclase activity in proximal straight tubules (PST) dissected from untreated but not collagenase-treated kidneys. Commercially available collagenase, which also contains other proteolytic enzymes, increased AVP-sensitive adenylate cyclase activity in control CCT, and trypsin treatment of CCT dissected without collagenase abolished the decrease in AVP-sensitive activity induced by potassium depletion. Inclusion of trypsin inhibitor during collagenase treatment of kidneys lowered AVP response in CCT from potassium-depleted rabbits. These results demonstrate that potassium depletion impairs hormone-sensitive adenylate cyclase of CCT (and PST) by a protease-sensitive mechanism.

EFFECT OF HUMAN CHORIONIC GONADOTROPHIN ON ADENYLATE CYCLASE ACTIVITY AND TESTOSTERONE CONTENT IN RAT TESTICULAR MITOCHONDRIA

1977 ◽  
Vol 75 (1) ◽  
pp. 119-126 ◽  
Author(s):  
SOREL SULIMOVICI ◽  
M. S. ROGINSKY
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Trophic Hormone

The adenylate cyclase activity and the concentration of testosterone in testicular mitochondria from immature rats were measured after administration of human chorionic gonadotrophin (HCG) or dibutyryl cyclic AMP in vivo or in vitro. Intratesticular injection of HCG produced an increase in adenylate cyclase activity which preceded the rise in the level of testosterone, whereas addition of the trophic hormone in vitro resulted in simultaneous increases. Administration of dibutyryl cyclic AMP in vivo enhanced the testosterone content of the mitochondria. However, the cyclic nucleotide added in vitro at concentrations up to 5 mmol/l had no effect. Cycloheximide injected intraperitoneally before the administration of HCG abolished the stimulatory effect of the trophic hormone on the level of testosterone in the mitochondria, whereas chloramphenicol had no effect. These results, although they confirm the role of cyclic AMP as an intermediate in the stimulatory effect of HCG on the concentration of testosterone in rat testis, do not support a role for mitochondrial adenylate cyclase in this action. A protein regulator(s) formed extramitochondrially appears to be involved in the stimulatory effect of gonadotrophins on steroidogenesis.

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