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Query: UNIPROT:P01275 (
glucagon
)
26,492
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Vasopressin has been shown previously to lower the
glucagon
-induced increase of cyclic AMP levels in isolated rat hepatocytes by way of an enhanced phosphodiesterase (EC 3.1.4.17) activity. Five phosphodiesterase inhibitors were tested for their ability to prevent vasopressin from lowering cyclic AMP levels in intact hepatocytes and for their inhibitory effect in vitro on soluble and particulate phosphodiesterase activities partially purified from hepatocytes. Three soluble activities have been separated by DEAE-cellulose chromatography: a phosphodiesterase hydrolyzing both cyclic AMP and
cyclic GMP
, a form stimulated by
cyclic GMP
and a cyclic AMP-specific activity. The absence of any statistically significant correlation between the in vivo (in intact cells) and the in vitro (on isolated phosphodiesterases) potencies of the inhibitors does not support a role for the cytosolic phosphodiesterases in mediating the vasopressin-induced decrease in cyclic AMP levels. No statistically significant correlation was observed between the inhibition of the vasopressin effect on cyclic AMP accumulation and the inhibition of phosphodiesterase activity either associated with the native plasma membranes or solubilized from these membranes with 0.4 M NaCl. In contrast, a statistically significant correlation was observed between the degree of inhibition of the vasopressin effect in the intact cells and the degree of inhibition of the intrinsic phosphodiesterase still associated with the plasma membranes after high-salt treatment. These data indicate that a phosphodiesterase activity integral to the plasma membrane is very likely involved in the negative control of cyclic AMP levels by vasopressin.
...
PMID:Involvement of a plasma membrane phosphodiesterase in the negative control of cyclic AMP levels by vasopressin in rat hepatocytes. 284 89
The influence of
cyclic 3',5'-guanosine monophosphate
(
cGMP
) on the lipolytic and antilipolytic (inhibition of
glucagon
-stimulated lipolysis) responses to GH (1 microgram/ml) was examined in chicken adipose tissue in vitro. Both 8-bromo-
cGMP
(0.1 mM) and sodium nitroprusside (1 mM) (a guanyl cyclase stimulator) completely inhibited the lipolytic effect of GH. A
cGMP
-lowering agent, LY83583 (10 microM), reversed the inhibitory effect of sodium nitroprusside on GH-stimulated lipolysis. Furthermore, the suppressive effects of insulin (100 ng/ml), insulin-like growth factor I (IGF-I) (100 ng/ml), or insulin-like growth factor II (IGF-II/MSA) (100 ng/ml), but not somatostatin (1 ng/ml), on GH-stimulated lipolysis were prevented by LY83583 addition. Neither 8-bromo-
cGMP
, sodium nitroprusside, nor LY83583 altered GH-induced inhibition of
glucagon
(1 ng/ml)-stimulated lipolysis. It is proposed that
cGMP
may mediate inhibitory control of GH-stimulated lipolysis by insulin, IGF-I, and IGF-II in chicken adipose tissue.
...
PMID:Inhibition of growth hormone-induced lipolysis by 3',5'-guanosine monophosphate in chicken adipose tissue in vitro. 284 72
Derangements in leukocyte function occur in patients with primary hyperparathyroidism and in those with uremia, which is a state of secondary hyperparathyroidism, suggesting that parathyroid hormone (PTH) may affect leukocyte function. We examined the interaction between PTH and random migration of human polymorphonuclear leukocytes (PMNL) utilizing a modified Boyden chamber. Intact 1-84 PTH but not its amino-terminal (1-34 PTH) or its carboxy-terminal (53-84 PTH) fragments produced marked and significant (p less than 0.01) stimulation of random migration in a dose-dependent manner. Inactivation of 1-84 PTH abolished its effect and other peptide hormones (calcitonin,
glucagon
, insulin and vasopressin) did not stimulate migration of PMNL. The effect of PTH on migration was not due to action of the hormone on chemotaxis. PTH did not enhance cAMP or
cGMP
production by PMNL. The stimulation of PMNL motility by PTH was independent of calcium concentration in media, was not mimicked by calcium ionophore and was not blocked by verapamil. Quinidine also produced significant (p less than 0.01) increase in random migration of PMNL and this effect was not additive to that of PTH. Prolonged exposure to PTH (16-20 h) was associated with significant inhibition of random migration of PMNL. The migration of PMNL from patients with advanced renal failure was significantly (p less than 0.01) reduced and there was a significant (p less than 0.01) inverse relationship between random migration of PMNL and serum levels of PTH. Also PTH produced only modest stimulation of random migration of PMNL in most patients with renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effect of parathyroid hormone on random migration of human polymorphonuclear leukocytes. 285 73
To clarify the role of the sympatho-adrenomedullary and renin-angiotensin-aldosterone systems, and catecholamine receptors, in the pathogenesis of orthostatic hypotension in diabetes mellitus (DM), urinary excretion of catecholamines, and plasma levels of norepinephrine (PNE), epinephrine (PE), renin activity (PRA), aldosterone (PAC), cyclic AMP (PcAMP) and
cyclic GMP
(PcGMP) were measured in 16 normal subjects (N) and 50 diabetic patients with or without orthostatic hypotension (DMOH(+), DMOH(-)). Changes in PNE, PE, PRA, PAC, PcAMP and PcGMP by standing,
glucagon
(G) administration and cold pressor test were examined. Furthermore, the effect of metoclopramide on catecholamine levels and blood pressure was investigated before and after cold pressor test. The results were following; (1) Urinary free norepinephrine excretion was significantly lower in DMOH(+), while urinary total norepinephrine excretion was normal in the two DM groups. Urinary free and total epinephrine excretions were lower in DMOH(+) than in N and DMOH(-). (2) PNE and PE were elevated after standing in all groups tested, and more pronounced in some cases of DMOH(+). Although PRA and PAC were elevated normally after standing in all groups, a dissociation between the two parameters was seen in some cases of DM. PcAMP after standing was correlated with PE(r = 0.829). Basal PcGMP was high in many cases of DMOH(+). However, no difference in the elevation of PcGMP after standing was noted between N and the two DM groups. (3) Systolic blood pressure (SBP) rose markedly in only DMOH(+) from 146 +/- 27mmHg to 178 +/- 34mmHg 5 minutes after G administration. The increment of PNE and PE 5 minutes after G administration were similar in all groups. In only DMOH(+), the increase in PcAMP 15 minutes after G test was proportional (r = 0.498) to that of epinephrine. (4) Responses of SBP, PNE, PE and PAC to cold pressor test apparently improved after administration of metoclopramide (MC) in some patients with DM. These results suggest that not only organic disturbance of sympathetic nerves but also functional inhibition of norepinephrine release mediated by dopamine receptor, may play an important role in the pathogenesis of orthostatic hypotension in diabetes mellitus. It is considered that catecholamine secretion from the adrenal medulla in DMOH(+) is increased by hypotension induced by standing. Furthermore, the vascular response to catecholamines may be accelerated through the increment of the extrajunctional receptor in DMOH(+).(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:[The role of the sympatho-adrenomedullary system and adrenergic receptors in the pathogenesis of orthostatic hypotension in diabetes mellitus]. 285 93
1. Two directly-acting stimulants of soluble guanylate cyclase, glyceryl trinitrate (0.1 microM) and sodium azide (10 microM), and a receptor-mediated stimulant of particulate guanylate cyclase, atriopeptin II (10 nM), each elevated the
cyclic GMP
content of primary cultures of pig aortic endothelial cells without affecting the cyclic AMP content. 2. Two receptor-mediated stimulants of adenylate cyclase,
glucagon
(1 microM) and isoprenaline (10 microM), had no effect on the cyclic AMP or
cyclic GMP
content of these cells, but the directly acting stimulant, forskolin (30 microM), induced a small increase in cyclic AMP content. 3. Three agents that release endothelium-derived relaxing factor (EDRF); bradykinin (0.1 microM), ATP (10 microM) and ionophore A23187 (0.1 microM), each markedly elevated the
cyclic GMP
content of pig aortic endothelial cells, but acetylcholine (1 microM) had no effect. None of these agents had any effect on cyclic AMP content. 4. Two agents that potentiate the actions of EDRF; M & B 22948 (100 microM) and superoxide dismutase (30 units ml-1), each elevated the
cyclic GMP
content of pig aortic endothelial cells without affecting the cyclic AMP content. Pretreating cells with catalase (100 units ml-1) did not affect the rise in
cyclic GMP
content induced by superoxide dismutase (30 units ml-1). 5. Pretreatment of pig aortic endothelial cells with haemoglobin (10 microM) reduced the resting content of
cyclic GMP
and blocked the increase in
cyclic GMP
content induced by glyceryl trinitrate (0.1 microM), sodium azide (10 microM), bradykinin (0.1 microM), ATP (10 microM), ionophore A23187 (0.1 microM), M & B 22948 (100 microM) and superoxide dismutase (30 units ml-1), but not that induced by atriopeptin II (10 nM). 6. Pretreatment of pig aortic endothelial cells with an inhibitor of soluble guanylate cyclase, methylene blue (20 microM), had no effect on the resting content of
cyclic GMP
. Methylene blue (20 microM) blocked the increase in
cyclic GMP
content induced by glyceryl trinitrate (0.1 microM), M & B22948 (100 microM) and bradykinin (0.1 microM), but not that induced by atriopeptin II (10 nM). 7. The data show that soluble guanylate cyclase, particulate guanylate cyclase and adenylate cyclase are present in pig aortic endothelial cells. They further suggest that EDRF, produced spontaneously or in response to vasoactive agents, elevates endothelial
cyclic GMP
content by stimulating soluble guanylate cyclase. It is possible that this may serve as a feedback loop by which the endothelial cell modulates EDRF production.
...
PMID:Endothelium-derived relaxing factor and atriopeptin II elevate cyclic GMP levels in pig aortic endothelial cells. 289 77
This study examined the effects of transmural nerve stimulation, acetylcholine, adrenoceptor agonists and several peptides on the contractility of strips of human gallbladder in vitro. Acetylcholine caused concentration-related contractions of the tissues and the sensitivity to acetylcholine was similar in gallbladders with mild and severe chronic cholecystitis. Noradrenaline and adrenaline relaxed gallbladder strips, probably via beta 2-adrenoceptor stimulation. Transmural nerve stimulation always caused contractions, but in the presence of atropine inhibitory responses were demonstrable and these were antagonized by propranolol. There was no evidence of non-adrenergic inhibitory neural responses. Of the peptides tested, only cholecystokinin octapeptide (CCK-OP), gastrin, pentagastrin, substance P and caerulein caused contractions. Responses to CCK-OP, gastrin and pentagastrin were antagonized by dibutyryl
cyclic GMP
. Hormones which had no effect upon human gallbladder strips included motilin, secretin, bombesin, neurotensin,
glucagon
, vasopressin, VIP and somatostatin. Considerable differences therefore exist between human tissues and those from experimental animals with respect to the direct actions of neural and hormonal stimuli on gallbladder contractility.
...
PMID:Contractility of human gallbladder muscle in vitro. 297 88
Leukocyte migration inhibitory factor (LMIF) activity was tested before and after
glucagon
administration both in vivo and in vitro. In vivo
glucagon
1 mg i.v. vs saline administration inhibited LMIF production by T lymphocytes in 85.21% patients (p less than 0.01). In vitro
glucagon
in physiologic (125 pg/ml) and pharmacologic (50 ng/ml) doses increased the migration area vs PPD 250 microL (migration index 0.5127 vs 0.3210; p less than 0.05). These results show a significant inhibitory effect of
glucagon
upon LMIF activity. We suggest that
glucagon
acts by enhancement of the intralymphocytic cAMP/
cGMP
ratio (cyclic adenosine monophosphate/cyclic guanosine monophosphate).
...
PMID:Prevention of leukocyte migration inhibitory factor activity by glucagon. 298 74
Rat hepatocytes were used to demonstrate rapid, transient effects on the modulation state (defined as the fraction of the enzyme present in the catalytically active form) of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase, E.C. 1.1.1.34). Insulin elevated, while
glucagon
, cAMP or
cGMP
lowered HMG-CoA reductase modulation state within 10 to 15 min. These changes were accompanied by a parallel change in sterol synthesis. Total HMG-CoA reductase activity was not altered. Rapid modulation of HMG-CoA reductase activity therefore constitutes a viable in vivo control mechanism. By contrast to the hormones and second messengers, mevalonolactone lowered both HMG-CoA reductase modulation state and total reductase quantity.
...
PMID:Rapid modulation of rat hepatocyte HMG-CoA reductase activity by cyclic AMP or cyclic GMP. 299 25
Cyclic nucleotides are universal intermediary agents of hormones in the target tissues, however mechanisms of the regulation of the cAMP and
cGMP
content in the cell are rather complex and still obscure. More data have appeared of late on the involvement of blood serum lipoproteins in the regulation of various intracellular processes including adenylate cyclase activity. Therefore the purpose of the study was to investigate the effect of adrenaline, hydrocortisone,
glucagon
, insulin and blood serum lipoproteins on the cAMP and
cGMP
content in rat liver surviving sections. An attempt was made to study a cooperative effect of the above hormones and lipoproteins of various classes. The results obtained have shown that adrenaline and
glucagon
raise the cAMP level in rat liver surviving sections. The effect of adrenaline is mediated by beta-adrenoreceptors. Insulin lowers an increases the level of cAMP in liver sections determined by the effect of
glucagon
. A decrease of the initial cAMP content in response to insulin occurs after a short lag period. High density lipoproteins (HDLP3) reduce the cAMP content in liver surviving sections. A cooperative effect of lipoproteins of a very low density and adrenaline (or hydrocortisone) in the regulation of the cAMP content in the rat liver was revealed. The
cGMP
content in rat liver surviving sections does not change under the influence of the above hormones and lipoproteins.
...
PMID:[Effect of blood serum hormones and lipoproteins on levels of cAMP and cGMP in viable sections of rat liver]. 299 73
Our previous observations that serum cyclic 3',5'-nucleotide phosphodiesterase activity varied in thyroid disorders and was positively correlated with thyroid function stimulated us to investigate the phosphodiesterase levels in sera of patients with pituitary and adrenal disorders, and the response to
glucagon
in normal subjects. Both serum cyclic AMP phosphodiesterase (cyclic AMP-PDE) and cyclic GMP phosphodiesterase (
cyclic GMP
-PDE) activities were measured at a low substrate concentration. Serum cyclic AMP-PDE activity was elevated in five patients with phaeochromocytoma and was not elevated in patients with Cushing's syndrome or acromegaly, compared to the level in normal subjects. Increased enzyme activities returned to normal after resection of the tumours. Intramuscular injection of
glucagon
to five healthy subjects elevated cyclic AMP levels and cyclic AMP-PDE activity in plasma. These results imply that the increased cyclic AMP level by the activation of cyclase may have induced cyclic AMP-PDE in the target organ and the soluble cyclic AMP-PDE may leak into blood vessels from target organs.
...
PMID:High activity of cyclic 3',5'-nucleotide phosphodiesterase in sera of patient with phaeochromocytoma. 301 9
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