scholarly journals Guanylate cyclase. Subcellular distribution in cardiac muscle, skeletal muscle, cerebral cortex and liver

1976 ◽  
Vol 157 (3) ◽  
pp. 705-712 ◽  
Author(s):  
P V Sulakhe ◽  
S J Sulakhe ◽  
N L Leung ◽  
P J St Louis ◽  
R A Hickie
Keyword(s):  
Skeletal Muscle ◽  
Cerebral Cortex ◽  
Adenylate Cyclase ◽  
Cardiac Muscle ◽  
Guanylate Cyclase ◽  
Plasma Membranes ◽  
Specific Activity ◽  
Frog Heart ◽  
Dependent Atpase ◽  
Absolute Requirement

1. Guanylate cyclase of every fraction studied showed an absolute requirement for Mn2+ ions for optimal activity; with Mg2+ or Ca2+ reaction was barely detectable. Triton X-100 stimulated the particulate enzyme much more than the supernatant enzyme and solubilized the particulate-enzyme activity. 2. Substantial amounts of guanylate cyclase were recovered with the washed particulate fractions of cardiac muscle (63-98%), skeletal muscle (77-93%), cerebral cortex (62-88%) and liver (60-75%) of various species. The supernatants of these tissues contained 7-38% of total activities. In frog heart, the bulk of guanylate cyclase was present in the supernatant fluid. 3. Plasma-membrane fractions contained 26, 21, 22 and 40% respectively of the total homogenate guanylate cyclase activities present in skeletal muscle (rabbit), cardiac muscle (guinea pig), liver (rat) and cerebral cortex (rat). In each case, the specific activity of this enzyme in plasma membranes showed a five- to ten-fold enrichment when compared with homogenate specific activity. 4. These results suggest that guanylate cyclase, like adenylate cyclase, and ouabain-sensitive Na+ + K+-dependent ATPase (adenosine triphosphatase), is associated with the surface membranes of cardiac muscle, skeletal muscle, liver and cerebral cortex; however, considerable activities are also present in the supernatant fractions of these tissues which contain very little adenylate cyclase or ouabain-sensitive Na+ + K+-dependent ATPase activities.

Effect of Acute Removal of Potassium From the Body on Tissue Electrolytes

1958 ◽  
Vol 193 (3) ◽  
pp. 634-638 ◽  
Author(s):  
Yehia A. Habib ◽  
George C. Nichopoulos ◽  
Richard R. Overman
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Water Content ◽  
Extracellular Space ◽  
Specific Activity ◽  
Sodium Content ◽  
The Body ◽  
Potassium Content ◽  
Free Fluid ◽  
Blood Potassium

Following a 2-hour period of vividialysis against a potassium free fluid, the rate of loss of potassium from the blood of dogs was determined (using K42) as well as the electrolyte and water content of heart, liver and skeletal muscle. A significant increase in potassium content of cardiac muscle and in sodium content of liver was found. There was a definite decrease in the specific activity of muscle potassium as well as in the ratio of muscle to plasma specific activity. The rate of loss of blood potassium (K42 vascular slope) was diminished in animals in which an amount of potassium less than that originally present in the extracellular space was removed. The data exclude the heart, liver and skeletal muscle as the sites from which potassium removed in acute experiments was derived.

scholarly journals Binding of parathyroid hormone to bovine kidney-cortex plasma membranes

1973 ◽  
Vol 134 (4) ◽  
pp. 913-921 ◽  
Author(s):  
H. S. Sutcliffe ◽  
T. J. Martin ◽  
J. A. Eisman ◽  
R. Pilczyk
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Specific Activity ◽  
Specific Binding ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Bovine Kidney ◽  
Hormone Sensitive ◽  
Chloramine T

1. Plasma membranes were purified from bovine kidney cortex, with a fourfold increase in specific activity of parathyroid hormone-sensitive adenylate cyclase over that in the crude homogenate. The membranes were characterized by enzyme studies. 2. Parathyroid hormone was labelled with 125I by an enzymic method and the labelled hormone shown to bind to the plasma membranes and to be specifically displaced by unlabelled hormone. Parathyroid hormone labelled by the chloramine-t procedure showed no specific binding. 75Se-labelled human parathyroid hormone, prepared in cell culture, also bound to the membranes. 3. Parathyroid hormone was shown to retain biological activity after iodination by the enzymic method, but no detectable activity remained after chloramine-t treatment. 4. High concentration of pig insulin inhibited binding of labelled parathyroid hormone to plasma membranes and partially inhibited the hormone-sensitive adenylate cyclase activity in a crude kidney-cortex preparation. 5. EDTA enhanced and Ca2+ inhibited binding of labelled parathyroid hormone to plasma membranes. 6. Whereas rat kidney homogenates were capable of degrading labelled parathyroid hormone to trichloroacetic acid-soluble fragments, neither crude homogenates nor purified membranes from bovine kidney showed this property. 7. Binding of parathyroid hormone is discussed in relation to metabolism and initial events in hormone action.

Mg2+ and Mn2+ effects on membrane-bound and detergent-solubilized adenylate cyclase

1981 ◽  
Vol 59 (9) ◽  
pp. 748-756 ◽  
Author(s):  
George I. Drummond
Keyword(s):  
Skeletal Muscle ◽  
Adenylate Cyclase ◽  
Cardiac Muscle ◽  
Catalytic Site ◽  
Maximal Velocity ◽  
Regulatory Site ◽  
Muscle Enzyme ◽  
Membrane Bound ◽  
Stimulation Of

Mg2+ and Mn2+ stimulation of basal, F−, and guanyl-5′-yl imidodiphosphate (GPP(NH)P) stimulated adenylate cyclase in particulate and detergent-solubilized preparations of skeletal muscle, cardiac muscle, and erythrocytes was examined. Solubilization decreased the concentrations of Mg2+ required for half-maximal velocity and for saturation. Concentrations of Mn2+ required for saturation and for half-maximal velocity of particulate preparations was much lower than for Mg2+ and these values were not markedly reduced by solubilization. Particulate and soluble preparations were similarly stimulated by NaF and GPP(NH)P. Activation of the heart and skeletal muscle enzyme by NaF and GPP(NH)P greatly reduced the Mg2+ requirement; this was seen with both particulate and solubilized preparations. It is suggested that solubilization removes Mg2+ action at a regulatory site; MgATP and MnATP are both effective at the catalytic site, the latter producing higher Vmax.

Filipin-Sterol-Complexes in Finch and Mouse Cardiac Muscle

1981 ◽  
Vol 39 ◽  
pp. 504-505
Author(s):  
J. R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Sarcoplasmic Reticulum ◽  
Cardiac Muscle ◽  
Plasma Membranes ◽  
Frog Skeletal Muscle ◽  
Transverse Tubules ◽  
Topographic Features ◽  
Terminal Cisterna ◽  
Close Proximity

We have recently reported that in frog skeletal muscle the plasma membranes, including the transverse tubules, are densely populated by filipin-sterol-complexes (FC), and that in the sarcoplasmic reticulum (SR) the FC are found much less commonly than in the plasma membrane, but that they have a predilection for the junctional SR (terminal cisterna) which in skeletal muscle are very large cisternae that are in close proximity to the plasma membrane. The analogous junctional SR of cardiac muscle shares all anatomical and topographic features with the junctional SR of skeletal muscle, except that in the latter the junctional SR is much larger. Ue have considered the possibility that the proximity of the junctional SR to the plasma membrane, the latter being replete with FC, may be related to the predilection of the FC for junctional SR in skeletal muscle.

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