scholarly journals Effect of serum lipoproteins on the adenylate cyclase activity of rat liver plasma membranes

1981 ◽  
Vol 196 (3) ◽  
pp. 899-902 ◽  
Author(s):  
G Ghiselli ◽  
C R Sirtori ◽  
S Nicosia
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
High Density Lipoproteins ◽  
Low Density ◽  
Serum Lipoproteins ◽  
Maximal Increase ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes ◽  
Active Class

Four rat lipoprotein classes [lymph chylomicrons, VLD (very-low-density), LD (low-density) and HD (high-density) lipoproteins] were tested for their ability to affect basal adenylate cyclase (EC 4.6.1.1) activity of rat liver plasma membranes. All the lipoproteins, with the exception of lymph chylomicrons, effectively increase the enzyme activity. VLD lipoproteins are the most active class (67% maximal increase), followed by HD lipoproteins (33%) and LD lipoproteins (23%). The effect of VLD lipoproteins is additive to that elicited by GTP or GTP plus glucagon (at least within a certain concentration range). VLD lipoproteins affect only the Vmax. of the enzyme, not the Km.

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 4-hydroxynonenal on adenylate cyclase and 5′-nucleotidase activities in rat liver plasma membranes

1985 ◽  
Vol 53 ◽  
pp. 209-217 ◽  
Author(s):  
Luciana Paradisi ◽  
Carla Panagini ◽  
Maurizio Parola ◽  
Giuseppina Barrera ◽  
Mario U. Dianzani
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes

scholarly journals The effect of fluoride on the state of aggregation of adenylate cyclase in rat liver plasma membranes

1980 ◽  
Vol 188 (1) ◽  
pp. 137-140 ◽  
Author(s):  
B R Martin ◽  
J M Stein ◽  
E L Kennedy ◽  
C A Doberska
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
The State ◽  
Target Size ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes

Irradiation inactivation was used to monitor changes in the state of adenylate cyclase in rat liver plasma membranes in the presence of F-.F- caused a decrease in the target size from 328000 to 237000 at 0 degrees C and from 329000 to 219000 at 30 degrees C. Adenylate cyclase was activated by F- at both 0 degrees C and 30 degrees C. The effect of F- was biphasic, activating up to a concentration of 10mM and inhibiting at higher concentrations. If adenylate cyclase weas maximally activated with glucagon and p[NH]ppG ([beta gamma-imido]GTP) all concentrations of F- were inhibitory. The implications of the results with respect to the mechanism of activation of adenylate cyclase are discussed.

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