Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Insulin-releasing effects of glucagon-like peptides, glucagon and various nutrients were examined using tumour cells from a freshly resected human insulinoma and RINm5F cells. Insulin release by human insulinoma cells or RINm5F cells was not affected by 16.7 mM glucose. Both cell types exhibited secretory responses to 20 mM alanine, 25 mM K+ and 7.6 mM Ca2+. Insulin release by human insulinoma cells was enhanced at 2 x 10(-7) M by glucagon, GLP-1[1-37], GLP-1[7-36] and its N- and C-terminal fragments GLP-1[7-14] and GLP-1[31-37]. The intact peptides (2 x 10(-6)-2 x 10(-12) M) also stimulated insulin release by RINm5F cells, but neither of the fragments enhanced secretion. The cyclic AMP content of human insulinoma cells and RINm5F cells was increased by glucagon. GLP-1[7-36] (2 x 10(-8)-2 x 10(-10) M) increased cyclic AMP in RINm5F cells, but no additional effects were noted in these or human insulinoma cells. These results suggest that GLP-1[7-36] stimulates insulin release by a direct action on human and rat B-cells, partly involving modulation of intracellular cyclic AMP.
Diabetes Res 1990 Feb
PMID:Stimulatory effects of glucagon-like peptides on human insulinoma cells and insulin-releasing clonal RINm5F cells. 196 28

Calcitonin gene-related peptide (CGRP) is an intrapancreatic neuropeptide that is known to inhibit glucose-stimulated insulin secretion in rats. To study if this inhibition is a direct islet effect, isolated, overnight cultured, rat islets were incubated together with glucose (3.3 or 8.3 mM) and CGRP (10(-11) to 10(-6) M). It was found that insulin secretion stimulated by glucose (8.3 mM) was inhibited by 77% by CGRP at 10(-6) M (p less than 0.001) and by 48% by the peptide at 10(-7) M (p less than 0.05). To study the possible mechanism(s) behind this inhibition, we investigated the effects of CGRP (10(-6) M) on the efflux of 45Ca2+ and 86Rb+ (reflecting Ca2+ and K+ ion movements, respectively) from isolated, perifused, rat islets. Furthermore, we examined the influence of CGRP on the content of cyclic AMP in overnight cultured isolated rat islets. We found that the initial, immediate 2-8 min peak of glucose (16.7 mM)-stimulated 45Ca(2+)-efflux was not affected by CGRP. In contrast, when the peptide was added at min 20 after glucose introduction, i.e., when the peak 45Ca(2+)-efflux had vanished, a small decrease in 45Ca(2+)-efflux was observed (p less than 0.001). CGRP did not alter the 86Rb(+)-efflux at 8.3 mM glucose neither in the presence nor in the absence of extracellular Ca2+. The islet content of cyclic AMP after 30 min incubation was 19.1 +/- 3.1 fmol/islet at 3.3 mM glucose and increased to 36.0 +/- 5.7 fmol/islet at 16.7 mM glucose (p less than 0.05). CGRP (10(-6) M) completely abolished this increase.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes Res 1990 Sep
PMID:Calcitonin gene-related peptide inhibits insulin secretion studies on ion fluxes and cyclic AMP in isolated rat islets. 196 31

In past studies, we have demonstrated that in streptozotocin-induced diabetic or spontaneously diabetic (BB) animal models, low Km cAMP phosphodiesterase and calmodulin are decreased while a low MW inhibitor of calmodulin is increased. To extend these studies, we have determined the rate of [35S]-methionine incorporation into calmodulin in isolated fat cells from these diabetic animals, i.e. streptozotocin-induced diabetic and the BB rats, spontaneous diabetic rat, non-diabetic rat, and control. We found markedly decreased rates of synthesis of calmodulin in the fully diabetic BB rat. In order to investigate the mechanism of the reduced calmodulin biosynthesis, we probed poly A+ mRNA from control and diabetic rat livers with a calmodulin specific anti-sense oligonucleotide probe and found that the fully diabetic animals, streptozotocin-induced diabetic and genetically diabetic BB, contained markedly reduced levels of calmodulin transcripts. Thus, both calmodulin protein and its putative mRNA are decreased in diabetic rat liver. We believe that in uncontrolled diabetes, the observed elevation in the levels of cyclic AMP in plasma and tissue results in part from decreased activity of phosphodiesterase. The insulin-sensitive phosphodiesterase appears to be regulated by calmodulin. We hypothesize that cyclic AMP phosphodiesterase inactivation in diabetes results in part from insulin insufficiency and to a less well-defined genetic lesion leading to calmodulin down-regulation.
 ...
PMID:Expression of calmodulin gene is down-regulated in diabetic BB rats. 197 47

AMP deaminase from normal and diabetic rat hearts was separated on cellulose phosphate and quantitated by HPLC. From soluble fractions three different AMP deaminase activities, according to KCl elution from cellulose phosphate and percent of total activity were: 170 mM (85%), 250 mM (8%) and 330 mM (7%) KCl. The AMP deaminase activity which eluted with 170 mM KCl was resolved to two distinct peaks by HPLC anionic exchange. After 4 weeks of diabetes the heart enzyme profile change to: 170 mM (10%), 250 mM (75%) and 330 mM (15%). Once purified the four activities were kinetically distinct: 170 mM KCl cytosolic, AMP Km = 1.78, stimulated by ATP, GTP, NADP and strongly inhibited by NAD; 170 mM KCl mitochondria AMP Km = 17.9, stimulated by ATP, ADP; 250 mM KCl isozyme, AMP Km = 0.66, stimulated by ADP; and 330 mM KCl isozyme, AMP Km = 0.97, inhibited by ATP, NAD(P).
 ...
PMID:Changes in AMP deaminase activities in the hearts of diabetic rats. 202 37

To investigate the influence of diabetes mellitus on vascular relaxation response, acetylcholine (ACh)-induced relaxation and production of cyclic GMP and cyclic AMP in aortic rings with endothelium were compared between alloxan-induced diabetic and control rabbits. ACh-induced relaxation was significantly attenuated in the aortic rings of diabetic rabbits. Concentration-response curve for ACh-induced relaxation in the aortic rings of control rabbits was shifted to the right by the pretreatment with hemoglobin, and this concentration-response curve was almost identical to that in the aorta from diabetic rabbits. Sodium nitroprusside (SNP)-induced relaxation in the aortic rings without endothelium from diabetic rabbits was similar to that in the aortic rings without endothelium from control rabbits. Basal levels of cyclic GMP and ACh-induced production of cyclic GMP were markedly lower in diabetic rabbits than those in control rabbits. On the other hand, there were no differences in basal and ACh-induced production of cyclic AMP between diabetic and control aorta. These results suggest that impairment of endothelium but not guanylate cyclase activity may be occurred in the aorta of diabetic rabbits. This impairment leads to the decrease in production of cyclic GMP through the attenuation of endothelium-derived relaxing factor (EDRF) release, and this may be responsible for the decreased endothelium-dependent relaxation of ACh.
 ...
PMID:Decrease in endothelium-dependent relaxation and levels of cyclic nucleotides in aorta from rabbits with alloxan-induced diabetes. 216 Nov 18

The present work demonstrates that phenformin exerted an inducing effect on delta-aminolevulinic acid synthase (ALA-S) and ferrochelatase activities and on cytochrome P-450 content in isolated hepatocytes from rats with experimental diabetes. Similar results were obtained with respect to ALA-S activity and cytochrome P-450 content when chlorpropamide was used. The inducing effect exerted by allylisopropylacetamide (AIA) on ALA-S and ferrochelatase activities in diabetic hepatic cells was markedly greater than that observed in normal hepatocytes. This stimulatory response was not enhanced by adding dibutyryl cyclic AMP (cAMP). When phenformin was added to isolated rat hepatocytes of normal rats, induction of ALA-S and ferrochelatase activities and cytochrome P-450 content was observed only in the presence of added dibutyryl cAMP. Addition of chlorpropamide to this in vitro system did not exert an inducing effect on the same enzymes even in the presence of dibutyryl cAMP. The present results add more experimental evidence about the lability of the heme pathway of diabetic hepatocytes.
 ...
PMID:Studies on induction of delta-aminolevulinic acid synthase, ferrochelatase, cytochrome P-450 and cyclic AMP by phenformin. Chlorpropamide, allylisopropylacetamide and lead in hepatocytes from normal and experimental diabetic rats. 216 5

Isolated muscle cells from adult rat heart were used to study the involvement of G-proteins in the regulation of the glucose transporter by insulin and isoprenaline. Efficient modification of G-protein functions was established by measuring isoprenaline-stimulated cyclic AMP production, viability and ATP content after treating the cells with cholera toxin and pertussis toxin for 2 h. Under these conditions cholera toxin decreased the stimulatory action of insulin on 3-O-methylglucose transport by 56%, but pertussis toxin had no effect. Basal transport was not affected by toxin treatment. Isoprenaline increased 3-O-methylglucose transport by 63%. This effect was not mimicked by dibutyryl cyclic AMP, but was completely blocked by cholera toxin. Streptozotocin-diabetes abolished isoprenaline action and decreased stimulation of transport by 64%. Concomitantly, cholera-toxin sensitivity of glucose transport was lost in cells from diabetic animals. This was paralleled by a large decrease (87 +/- 4%) in mRNA expression of the insulin-regulatable glucose transporter, as shown by Northern-blot analysis of RNA isolated from cardiomyocytes of diabetic rats. These data suggest a functional association between the insulin-responsive glucose transporter and a cholera-toxin-sensitive G-protein mediating stimulation by insulin and isoprenaline.
 ...
PMID:G-protein-mediated regulation of the insulin-responsive glucose transporter in isolated cardiac myocytes. 217 73

An increased platelet-vessel wall interaction plays an important role in most forms of cardiovascular disease. In healthy arteries, the vascular endothelium prevents platelet adhesion and aggregation. As a mediator of this protective function, the endothelium produces prostacyclin, endothelium-derived nitric oxide and tissue plasminogen activator. Cardiovascular risk factors such as hypertension, hyperlipidemia and diabetes are associated with an increased platelet activation and with decreased antithrombotic properties of the blood vessel wall. The available inhibitors of platelet function interfere only with one of various mechanisms of platelet activation and of the platelet-vessel wall interaction. Prostaglandin inhibitors, such as aspirin and newer, more specific inhibitors, prevent the production and/or the effect of thromboxane A2 on platelets and the blood vessel wall. Other drugs interfere with the effect of adenosine diphosphate on platelets, or they increase intracellular concentration of cyclic GMP or AMP in platelets and vascular smooth muscle cells. The protective effects of platelet inhibitors in primary and particularly in secondary prevention of cardiovascular diseases have been documented in numerous studies. The successful clinical use of these substances, however, requires a selective prescription of the drugs in patients with cardiovascular disease.
 ...
PMID:[Thrombocyte inhibitors in cardiovascular therapy]. 221 49

A case of a 29-year-old woman with idiopathic hypoparathyroidism was reported. There were neither endocrine nor neurological disorders among her family, except for her mother's hearing loss. She had been suffering from insulin-dependent diabetes mellitus since 21 years of age, and was noticed to be hard of hearing for several years, but never been examined. At the age of 27, choreic movement on her left upper limb and gait disturbance appeared. A year before admission, gait disturbance gradually developed and she could not walk any more. On admission, her height was 137.2 cm and her weight 36.5 kg. She had a round face, uneven teeth and borderline metacarpal sign on her right hand. On neurological examination, Parkinsonism, bucco-lingo-masticatory dyskinesia and bilateral extensor planter reflex were present, but tetany was not observed anywhere. Serum calcium was 3.9 mEq/l, and serum phosphorus 5.3 mEq/l. A CT scan of brain revealed calcifications in the bilateral basal ganglia and thalami, low density area in the left putamen, and atrophy of both caudate nuclei. Serum PTH was less than 100 pg/ml. Ellsworth-Howard's test showed hyperresponsiveness in the secretion of urinary phosphorus and cyclic-AMP. Other endocrinological studies showed no abnormality except for hyporesponsiveness in the secretion of insulin on glucose tolerance test. On the basis of these results, a diagnosis of idiopathic hypoparathyroidism with insulin-dependent diabetes mellitus was made. Administration of alfacalcidol returned serum calcium and phosphorus to normal with considerable clinical benefit. Parkinsonism was gradually improved and she became to be able to walk with a cane after one year of treatment. But buco-lingo-masticatory dyskinesia were not reduced.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[A case of idiopathic hypoparathyroidism with extrapyramidal signs and insulin-dependent diabetes mellitus]. 222 58

A study of graded exercise tolerance (GET), indices of central hemodynamics and energy metabolism in 136 patients with insulin-dependent diabetes mellitus and 35 controls aged 16 to 40 has shown reduced GET in 86% of the patients. It was combined with a decrease in the CVS functional potentialities and disorder of energy formation. The lowest level of GET was noted in patients with a severe type of diabetes mellitus in marked decompensation, with disease of 10 yrs. of duration at advanced stages of diabetic microangiopathies. The use of inosine and AMP is accompanied by a rise of GET and the activity of energy producing systems.
 ...
PMID:[The mechanisms of a decreased tolerance for graduated physical loading in young patients suffering from diabetes mellitus]. 233 Mar 55


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>