scholarly journals Effect of adrenalectomy on acceleration of gluconeogenesis by calcium ions, adenosine 3′:5′-cyclic monophosphate and adrenaline in rat kidney tubules

1978 ◽  
Vol 174 (2) ◽  
pp. 641-646 ◽  
Author(s):  
D W R MacDonald ◽  
E D Saggerson
Keyword(s):  
Cyclic Amp ◽  
Calcium Ions ◽  
Beta Blocker ◽  
Rat Kidney ◽  
Male Rats ◽  
Kidney Tubules ◽  
Cyclic Monophosphate ◽  
Alpha Blocker ◽  
Adrenalectomized Rats ◽  
Stimulation Of

1. Gluconeogenesis from pyruvate was measured in renal-cortical-tubules fragments prepared from fed male rats 6-8 days after adrenalectomy or sham adrenalectomy. The response of this process to 3′:5′-cyclic AMP and adrenaline was compared in these two states at two Ca2+ concentrations. 2. Adrenalectomy decreased the percentage stimulation of gluconeogenesis by 3′:5′-cyclic AMP, but increased percentage stimulation by adrenaline. Cortisol treatment of adrenalectomized rats (50 mg/kg, twice daily for 2 days) did not reverse the change in responsiveness to 3′:5′-cyclic AMP and adrenaline. 3. Stimulation of gluconeogenesis by 1 micron-adrenaline was unaffected by 10 micron-propranolol (beta-blocker) in either state. Phentolamine (alpha-blocker; 10 micron) totally blocked stimulation of gluconeogenesis by 1 micron-adrenaline in the sham-operated condition, but was only partially effective in this respect after adrenalectomy.

scholarly journals β-adrenergic control of phosphatidylcholine synthesis by transmethylation in hepatocytes from juvenile, adult and adrenalectomized rats

1983 ◽  
Vol 216 (3) ◽  
pp. 675-680 ◽  
Author(s):  
D Marin-Cao ◽  
V Alvarez Chiva ◽  
J M Mato
Keyword(s):  
Cyclic Amp ◽  
Rat Liver ◽  
Beta Blocker ◽  
Cyclic Amp Accumulation ◽  
Adrenergic Control ◽  
Beta Receptors ◽  
Dose Dependent ◽  
Phosphatidylcholine Synthesis ◽  
Adrenalectomized Rats ◽  
Stimulation Of

Changes in isoprenaline-sensitive phospholipid methyltransferase were studied in hepatocytes isolated from juvenile, mature and adrenalectomized rats. Isoprenaline produced greater stimulation of cyclic AMP accumulation in juvenile and mature adrenalectomized rats than in mature animals. Similarly, isoprenaline stimulated phospholipid methyltransferase in juvenile and mature adrenalectomized rats but had no effect in mature animals. Isoprenaline-mediated activation of phospholipid methyltransferase in adrenalectomized rats was time- and dose-dependent. In hepatocytes isolated from adrenalectomized rats incubated with [Me-3H]methionine or [3H]-ethanolamine the addition of isoprenaline increased the amount of radioactivity incorporated into phosphatidylcholine. The activation by isoprenaline of phospholipid methyltransferase was abolished by the beta-blocker propranolol and by insulin. These results indicate that rat liver the occupation of functional beta-receptors causes a stimulation of phospholipid methylation. It is suggested that, as reported previously, cyclic AMP activates phospholipid methyltransferase.

Dynamic changes in plasma luteinizing hormone and testosterone after stress in the male rat. Influence of adrenalectomy

1984 ◽  
Vol 62 (9) ◽  
pp. 1231-1233 ◽  
Author(s):  
Gérard Lescoat ◽  
Denise Lescoat ◽  
Danièle Garnier
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Level ◽  
Male Rats ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Intact Male ◽  
Dynamic Changes ◽  
High Level ◽  
Adrenalectomized Rats ◽  
Stimulation Of

In 60-day old intact male rats, stress imposed by a strange environment increased the levels of plasma LH and testosterone. Adrenalectomy, performed at 50 days of age, decreased plasma level of testosterone in basal conditions. However, without affecting the plasma level of LH significantly, stress increased plasma testosterone, albeit to a lesser extent, in the adrenalectomized rats. Stimulation of the testicular secretion by the high level of ACTH seems to be the most likely explanation for the observed testosterone peak in the adrenalectomized rat.

scholarly journals Effect of compound D-600 (methoxyverapamil) on gluconeogenesis and on acceleration of the process by α-adrenergic stimuli in rat kidney tubules

1980 ◽  
Vol 190 (2) ◽  
pp. 283-291 ◽  
Author(s):  
E D Saggerson ◽  
C A Carpenter
Keyword(s):  
Renal Cortex ◽  
Rat Kidney ◽  
Sodium Lactate ◽  
Kidney Tubules ◽  
Alpha Adrenoceptor ◽  
Adrenoceptor Antagonist ◽  
Adrenoceptor Agonist ◽  
Adrenoceptor Blocker ◽  
Glucose Formation ◽  
Stimulation Of

1. Tubule fragments were isolated from renal cortex of fed rats and glucose formation was measured after incubation with 5 mM-sodium lactate. 20 Compound D-600 (10-100 microM) decreased gluconeogenesis from lactate. This inhibition of the process by compound D-600 increased with increasing extracellular Ca2+ concentration, was overridden by noradrenaline and diminished by starvation for 24 h. 3. Inhibition of lactate-supported gluconeogenesis by compound D-600 was not prevented by the alpha 1-adrenoceptor antagonist thymoxamine. 4. Compound D-600 had little effect on gluconeogenesis from 2-oxoglutarate and increased gluconeogenesis from succinate. 5. Compound D-600 opposed stimulation of gluconeogenesis by noradrenaline or oxymetazoline (a selective alpha-adrenoceptor agonist) in a manner suggesting that compound D-600 is an alpha-adrenoceptor blocker. Oxymetazoline was more sensitive than noradrenaline to blockade by both compound D-600 and by the conventional alpha-adrenoceptor antagonist phentolamine. Noradrenaline became more sensitive to blockade by compound D-600 when extracellular Ca2+ was decreased. 6. Compound D-600 did not block stimulation of gluconeogenesis by angiotensin or cyclic AMP.

The Effect of Aging on β-Adrenoceptor-Stimulated Cyclic AMP Formation in Human Lymphocytes

1981 ◽  
Vol 60 (5) ◽  
pp. 587-589 ◽  
Author(s):  
C. A. Kraft ◽  
C. M. Castleden
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Binding Assay ◽  
Human Lymphocytes ◽  
Phosphodiesterase Inhibitor ◽  
Adenylate Cyclase System ◽  
Competitive Binding Assay ◽  
Cyclic Monophosphate ◽  
Maximal Stimulation ◽  
Stimulation Of

1. Responsiveness of the β-adrenoceptor adenylate cyclase system was measured in lymphocytes from healthy young and old subjects by incubating the cells with isoprenaline in the presence of a phosphodiesterase inhibitor and by measuring production of adenosine 3′:5′-cyclic monophosphate (cyclic AMP) with a competitive binding assay. 2. The two groups did not differ significantly in the levels of cyclic AMP produced or in the concentration of isoprenaline required to give half-maximal stimulation of the cells (ED50).

scholarly journals A study of 3′:5′-cyclic mononucleotide-dependent protein kinase from canine prostate glands

1974 ◽  
Vol 144 (2) ◽  
pp. 377-383 ◽  
Author(s):  
B K Tsang ◽  
R L Singhal
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Metal Ion ◽  
Maximum Velocity ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Cyclic Monophosphate ◽  
Diethylaminoethyl Cellulose ◽  
Dependent Protein ◽  
Stimulation Of

1. An adenosine 3′:5′-cyclic monophosphate (cyclic AMP)-dependent protein kinase, located predominantly in the cytosol, was studied in canine prostate. 2. The enzyme exhibited cyclic AMP-binding activity, and could be isolated by chromatography on diethylaminoethyl cellulose. 3. The enzyme was maximally stimulated (fourfold) by 1μm-cyclic AMP, and half-maximal activation of the enzyme was observed in presence of 50nm-cyclic AMP. 4. Equilibrium studies at pH5.0 indicated the presence of one major class of binding site for cyclic AMP, with an association constant of approx. 108m-1. 5. Stimulation of the enzyme was also observed with the 3′:5′-cyclic monophosphate derivatives of cytidine, inosine, guanosine and uridine as well as with dibutyryl cyclic AMP, but higher concentrations of these cyclic nucleotides were required to provide the same degree of activation as that seen with cyclic AMP. 6. Comparing α-casein, protamine and different histone subfractions as substrates, highest cyclic AMP stimulation was demonstrated with histones. 7. Although maximum velocity of the enzyme was enhanced approximately fivefold in presence of cyclic AMP, kinetic studies indicated that the apparent Km for histone (0.5mg/ml) remained the same whether determined in the presence or absence of the cyclic nucleotide. 8. In addition, cyclic AMP did not significantly change the apparent Km for ATP (1.2×10-5m). 9. The purified enzyme showed an absolute requirement for bivalent metal ion. Substitution of Mn2+for Mg2+decreased basal protein kinase activity as well as the stimulation noted with cyclic AMP. Similarly, the basal activity was lowered when Mg2+was replaced by Ca2+and cyclic AMP produced only little stimulation of the prostatic enzyme.

EFFECTS OF VAGAL STIMULATION, VAGOTOMY AND ADRENALECTOMY ON RELEASE OF INSULIN IN THE RAT

1980 ◽  
Vol 85 (1) ◽  
pp. 131-136 ◽  
Author(s):  
TAKEO SAKAGUCHI ◽  
KEN'ICHI YAMAGUCHI
Keyword(s):  
Vagus Nerve ◽  
Plasma Insulin ◽  
Vagal Stimulation ◽  
Physiological Role ◽  
Male Rats ◽  
Pentobarbitone Sodium ◽  
Potent Factor ◽  
Adrenalectomized Rats ◽  
Stimulation Of

SUMMARY To evaluate the physiological role of the vagus nerve in the secretion of insulin in the rat, changes in plasma levels of insulin and sugar were examined after vagotomy with and without adrenalectomy. Male rats, fasted for 22 h, weighing about 300 g and anaesthetized with pentobarbitone sodium were used. Thirty minutes after unilateral or bilateral adrenalectomy, the first blood sample was taken just before pancreatic vagotomy and a second sample was taken 15 min after vagotomy. Pancreatic vagotomy significantly decreased levels of plasma insulin in bilaterally adrenalectomized rats. It was also confirmed that electrical stimulation of the pancreatic vagus nerve provoked an increase in levels of insulin associated with a reduction of carbohydrates in the blood. These observations support the theory that there is a vagal mechanism which modulates the secretion of insulin and suggest that the vagal mechanism is a potent factor although such a mechanism may be masked by the activity of the adrenal gland.

DDT-Induced Stimulation of Key Gluconeogenic Enzymes In Rat Kidney Cortex

1972 ◽  
Vol 50 (2) ◽  
pp. 225-229 ◽  
Author(s):  
S. Kacew ◽  
R. L. Singhal ◽  
G. M. Ling
Keyword(s):  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Glucocorticoid Hormones ◽  
Rat Kidney Cortex ◽  
Gluconeogenic Enzymes ◽  
Maximal Stimulation ◽  
Adrenalectomized Rats ◽  
Stimulation Of

Administration of technical DDT or o,p′-DDT produced marked increases in pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-diphosphatase, and glueose-6-phospfaatase activities in rat kidney cortex. Significant increases in these key gluconeogenic enzymes occurred at 2–3 days and maximal stimulation was seen 5–7 days after the beginning of o,p′-DDT treatment. This DDT isomer, when given to adrenalectomized rats, produced increases in renal enzymes similar to those observed in intact animals. Furthermore, since administration of triamcinolone to o,p′-DDT-treated rats failed to potentiate the action of this insecticide on various enzymes, evidence indicates that the stimulation of kidney cortex gluconeogenesis by DDT is not mediated through a release of glucocorticoid hormones from the adrenal cortex.

scholarly journals The influence of intracellular levels of cyclic nucleotides on cell proliferation and the induction of antibody synthesis.

1975 ◽  
Vol 141 (1) ◽  
pp. 97-111 ◽  
Author(s):  
J Watson
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Cyclic Nucleotides ◽  
Precursor Cells ◽  
Cyclic Monophosphate ◽  
The Absolute ◽  
Stimulation Of ◽  
Mitogenic Signal

The intracellular ratio of adenosine 3',5'-cyclic monophosphate (cyclic AMP) to guanosine 3',5'-cyclic monophosphate (cyclic GMP) may control the developmental pathway followed by antibody-forming cell (AFC) precursors. The evidence for this is derived from several different types of experiments. First lipopolysaccharide (LPS) which is mitogenic for B lymphocytes, stimulates rapid, transient changes in intracellular levels of cyclic GMP but not cyclic AMP when added to mouse spleen cultures. Cyclic GMP itself stimulates DNA synthesis in these cultures, suggesting that the intracellular changes in cyclic GMP levels are involved in the mitogenic signal delivered by LPS to cells. The absolute amounts of cyclic nucleotides may vary widely in different cells under various conditions, however, the intracellular ratio of cyclic AMP to cyclic GMP is always high in nondividing cells and low in dividing cells. AFC precursors appear to respond to antigen in the absence of T-cell activity by inactivation (1-7). In the response to antigen in the presence of specific T cells, precursor cells proliferate and mature to AFC. Raising intracellular levels of cyclic AMP inhibits cell proliferation and leads to precursor cell inactivation (14, 15). It is suggested that the interaction of antigen with immunoglobulin receptors on the surface of precursors cells leads to the stimulation of adenylate cyclase activity and initiates the inactivation pathway. Since cyclic GMP stimulates immune responses in T-cell-depleted cultures (14, 15) and increasing cyclic GMP levels appear to be involved in the delivery of a mitogenic signal to cells, it is suggested that T-helper cells deliver a signal to precursor cells via the stimulation of guanylate cyclase to initiate the inductive pathway. It is suggested that it is the intracellular ratio of cyclic AMP to cyclic GMP that regulates the fate of precursor cells, not the absolute level of one cyclic nucleotide.

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