Dependence of Platelet Adenyl Cyclase System on Oxidative Phosphorylation

1975 ◽  
Vol 34 (01) ◽  
pp. 042-049 ◽  
Author(s):  
Shuichi Hashimoto ◽  
Sachiko Shibata ◽  
Bokro Kobayashi
Keyword(s):  
Cyclic Amp ◽  
Oxidative Phosphorylation ◽  
Sodium Succinate ◽  
Potassium Cyanide ◽  
Adenyl Cyclase ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Adenyl Cyclase Activity ◽  
Intact Rabbit ◽  
Adenyl Cyclase System ◽  
Cyclic Amp Synthesis

SummaryThe radioactive adenosine 3′,5′-monophosphate (cyclic AMP) level derived from 8-14C adenine in intact rabbit platelets decreased in the presence of mitochondrial inhibitor (potassium cyanide) or uncoupler (sodium azide), and markedly increased by the addition of NaF, monoiodoacetic acid (MIA), or 2-deoxy-D-glucose. The stimulative effect of the glycolytic inhibitors was distinctly enhanced by the simultaneous addition of sodium succinate. MIA did neither directly stimulate the adenyl cyclase activity nor inhibit the phosphodiesterase activity. These results suggest that cyclic AMP synthesis in platelets is closely linked to mitochondrial oxidative phosphorylation.

ADENYL CYCLASE AND PHOSPHODIESTERASE ACTIVITY IN THE ISOLATED ISLETS OF LANGERHANS OF OBESE MICE AND THEIR LEAN LITTER MATES: THE EFFECT OF GLUCOSE, ADRENALINE AND DRUGS ON ADENYL CYCLASE ACTIVITY

1971 ◽  
Vol 51 (1) ◽  
pp. 67-78 ◽  
Author(s):  
T. ATKINS ◽  
A. J. MATTY
Keyword(s):  
Adrenergic Receptor ◽  
Adenyl Cyclase ◽  
Cyclase Activity ◽  
Obese Mice ◽  
Receptor Function ◽  
Phosphodiesterase Activity ◽  
Camp Phosphodiesterase ◽  
Adenyl Cyclase Activity ◽  
Isolated Islets Of Langerhans ◽  
Adenyl Cyclase System

SUMMARY Radiometric estimations of adenyl cyclase and cyclic AMP (cAMP) phosphodiesterase showed significantly higher enzyme activities in the islet tissue of obese-hyperglycaemic mice than in that of their normal litter mates, but the ratios of the two enzymes in both types of islets were found to be the same, i.e. 1:1. Adenyl cyclase and phosphodiesterase activity increased linearly with incubation time and protein concentration. Sodium fluoride (10 mmol/1) increased cyclase activity in the islets of obese mice by 33·4%; theophylline (10 mmol/1) in the presence of cAMP (1 mmol/1) reduced phosphodiesterase activity by almost 100%. Glucose (2 g/1) reduced, while adrenaline (10−5 mol/1) increased cyclase activity in islets from both normal and obese animals. An evaluation of the effects of α- and β-adrenergic receptor stimulating and blocking agents on islets of both normal and obese mice showed the stimulation of adenyl cyclase to be a β-adrenergic receptor function and the inhibition an α-adrenergic receptor function. The possible role of the adenyl cyclase system in diabetes mellitus and insulin secretion is discussed.

THE MECHANISM OF ACTION OF PARATHYROID HORMONE: LACK OF EVIDENCE FOR THE MEDIATION BY CYCLIC ADENOSINE 3′, 5′-MONOPHOSPHATE OF PARATHYROID HORMONE-STIMULATED PHOSPHATURIA

1970 ◽  
Vol 46 (2) ◽  
pp. 185-190 ◽  
Author(s):  
J. D. SALLIS
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Mechanism Of Action ◽  
Kidney Tissue ◽  
Adenyl Cyclase ◽  
Cyclase Activity ◽  
Kidney Cortex ◽  
Adenyl Cyclase Activity

SUMMARY The excretion of phosphate in the rat after renal infusion of parathyroid hormone or cyclic adenosine 3,′5′-monophosphate (AMP) is described. The hormone stimulated an immediate phosphaturia, but no such response was measurable in the presence of cyclic AMP. Adenyl cyclase activity in kidney cortex was assessed by measuring the conversion of [14C]adenosine 5′-triphosphate to [14C]cyclic AMP. Previous infusion of kidneys with parathyroid hormone did not alter adenyl cyclase activity but the addition of the hormone to kidney tissue in vitro caused a significant increase in the activity of this enzyme. It is suggested that the parathyroid hormone-stimulated phosphaturia is not mediated by cyclic AMP.

BABIES, HORMONES AND KIDNEYS—A NEW LOOK AT DEVELOPMENT

PEDIATRICS ◽  
1972 ◽  
Vol 50 (1) ◽  
pp. 3-4
Author(s):  
Wallace W. McCrory
Keyword(s):  
Cyclic Amp ◽  
Rat Kidney ◽  
Adenyl Cyclase ◽  
Endocrine Gland ◽  
Hormone Action ◽  
Abundant Evidence ◽  
Cell Target ◽  
Urinary Cyclic Amp ◽  
Adenyl Cyclase System

The role of cyclic AMP (adenosine 3’,5’-monophosphate) in hormone action is now quite firmly established. Abundant evidence now demonstrates that after release from an endocrine gland a hormone (first messenger) is transported to its effector cell (target) where it interacts with the adenyl cyclase system to release cyclic AMP (second messenger) which acts intracellularly to carry out the work of the hormone. In 1967, Chase and Aurbach demonstrated that urinary cyclic AMP, now known to be derived from both plasma and kidney, increased when parathormone (PTH) was administered to the rat and man. These workers also demonstrated a PTH-sensitive adenyl cyclase in the proximal tubules of the rat kidney and in fetal bone.

Urinary Excretion of Cyclic AMP by Cold-Acclimated Rats

1974 ◽  
Vol 52 (5) ◽  
pp. 414-417 ◽  
Author(s):  
Michelle Muirhead ◽  
Aileen Inglis ◽  
Jean Himms-Hagen
Keyword(s):  
Cyclic Amp ◽  
Metabolic Rate ◽  
Room Temperature ◽  
Metabolic Response ◽  
Adenyl Cyclase ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Adenyl Cyclase System ◽  
First Time ◽  
Noradrenaline And Adrenaline

Cold-acclimated rats living in the cold (4°) excrete more cyclic AMP in their urine than do control warm-acclimated rats living at room temperature (26°–28°). However, cold-acclimated rats, returned to the cold after a few days at room temperature and presumably raising their metabolic rate by nonshivering thermogenesis in response to the noradrenaline and adrenaline secreted by the sympathetic nervous system, excrete the same amount of cyclic AMP in their urine as do warm-acclimated rats of the same age put into the cold for the first time and presumably raising their metabolic rate by shivering. Thus, no evidence could be found for an altered utilization of the adenyl cyclase system in the cold-acclimated rat. This, together with previous findings of unaltered levels and properties of noradrenaline-stimulated adenyl cyclase in brown adipose tissue and skeletal muscle of cold-acclimated rats, leads us to the conclusion that the enhancement of the metabolic response to noradrenaline in cold-acclimated rats is not due to any alteration in the adenyl cyclase system.

scholarly journals Lanthanum: inhibition of ACTH-stimulated cyclic AMP and corticosterone synthesis in isolated rat adrenocortical cells.

1976 ◽  
Vol 68 (1) ◽  
pp. 142-153 ◽  
Author(s):  
A Haksar ◽  
D V Maudsley ◽  
F G Péron ◽  
E Bedigian
Keyword(s):  
Cyclic Amp ◽  
Adrenal Cortex ◽  
Binding Sites ◽  
Adenyl Cyclase ◽  
Microscope Examination ◽  
Ca Antagonist ◽  
Corticosterone Response ◽  
Adenyl Cyclase System ◽  
Stimulation Of

Lanthanum (La+++) is a well-known Ca++ antagonist in a number of biological systems. It was used in the present study to examine the role of Ca++ in the regulation of adenyl cyclase of the adrenal cortex by ACTH. In micromolar concentrations, .La+++ inhibited both cyclic AMP and corticosterone response of isolated adrenal cortex cells to ACTH. However, a number of intracellular processes were not affected by La+++. These include the stimulation of steroidogenesis by dibutyryl cyclic AMP, conversion of several steroid precursors into corticosterone, and stimulation of the latter by glucose. Thus, inhibition of steroidogenesis by La+++ appears to be solely due to an inhibition of ACTH-stimulated cyclic AMP formation. Electron microscope examination showed that La+++ was localized on plasma membrane of the cells and did not appear to penetrate beyond this region. Since La+++ is believed to replace Ca++ at superficial binding sites on the cell membrane, it is proposed that Ca++ at these sites plays an important role in the regulation of adenyl cyclase by ACTH. Similarities in the role of Ca++ in "excitation-contraction" coupling and in the ACTH-adenyl cyclase system raise the possibility that a contractile protein may be involved in the regulation of adenyl cyclase by those hormones which are known to require Ca++ in the process.

Cyclic AMP and adenyl cyclase in brain tumors

1977 ◽  
Vol 46 (4) ◽  
pp. 477-483 ◽  
Author(s):  
Mathilda A. Furman ◽  
Kenneth Shulman
Keyword(s):  
Cyclic Amp ◽  
Brain Tumors ◽  
Human Brain ◽  
Adenosine Monophosphate ◽  
Adenyl Cyclase ◽  
Cyclase Activity ◽  
Normal Brain ◽  
Similar Response ◽  
Adenyl Cyclase Activity ◽  
Content Type

✓ Some of the regulatory mechanisms of cyclic adenosine monophosphate (AMP) production in human brain tumors were investigated by assessing both cyclic AMP levels and adenyl cyclase activity. A large disparity was found between the levels of cyclic AMP of normal brain and brain-tumor tissue. Cyclic AMP levels were much lower in brain tumors (25.8 pmoles (picomoles)/mg protein) than in normal brain (98.8 pmoles/mg protein). These studies also show that the abnormally low levels of cyclic AMP in tumors parallel those of adenyl cyclase. The mean adenyl cyclase activity of brain tissue was found to be 111.0 pmoles of cyclic AMP/min/mg protein, while that of the tumor was only 23.0 pmoles/min/mg protein. Levels of cyclic AMP and adenyl cyclase activity were inversely related to the degree of malignancy. Attempts to stimulate adenyl cyclase in homogenates of human brain and brain tumors resulted in a similar response in both tissues. Norepinephrine was the most effective stimulant and produced a two- to threefold increase in cyclic AMP production, while histamine had no effect. It is concluded that one of the factors governing tumor growth may be a defect in the adenyl cyclase system.

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