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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum concentrations of ionized calcium, parathyroid hormone, and calcitonin were measured during zinc infusion in patients of short stature (n = 15); those with insulin-dependent diabetes mellitus (n = 13); and age-matched controls (n = 10). The increase in serum zinc concentrations after zinc infusion resulted in a decrease in the serum calcitonin concentrations but not in concentrations of ionized calcium and parathyroid hormone. A significant negative correlation was obtained between body zinc clearances and decreases in serum calcitonin levels at 60 minutes after the infusion of zinc. Thus, we found a relationship between infusion of zinc and the regulation of calcitonin secretion. We propose that an increase in the serum zinc pool plays a definite role in inhibiting calcitonin secretion from thyroid tissue.
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PMID:Infusion of zinc inhibits serum calcitonin levels in patients with various zinc status. 193 83

Hypothalamic tissue levels of nine regulatory peptides (bombesin, calcitonin gene-related peptide [CGRP], galanin, neuromedin B, neuropeptide Y [NPY], neurotensin, somatostatin, substance P, and vasoactive intestinal peptide [VIP]) were compared in Aston obese diabetic (ob/ob) and lean (+/?) mice aged 4, 16, and 28 weeks. Neurotensin concentrations were significantly lower in ob/ob mice than in lean mice, with a 20% reduction (P = .03) in the whole hypothalamus at 4 weeks of age, a 24% reduction (P = .009) in the lateral hypothalamus at 16 weeks, and a 50% reduction (P = .0007) in the central hypothalamus at 28 weeks of age. Apart from a 42% increase in vasoactive intestinal peptide concentrations in the central hypothalamus of ob/ob mice at 28 weeks (P = .02), levels of the other eight peptides examined did not differ significantly between obese and lean groups. Neurotensin is known to cause anorexia and increased energy expenditure when injected into the central hypothalamus. Reduced hypothalamic neurotensin concentrations may reflect reduced neurotensinergic activity, which might contribute to hyperphagia and decreased energy expenditure, two major defects that contribute to obesity and diabetes in the ob/ob syndrome.
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PMID:Reduced hypothalamic neurotensin concentrations in the genetically obese diabetic (ob/ob) mouse: possible relationship to obesity. 194 36

In diabetic animals, there is a decrease in serum 1,25-dihydroxyvitamin D [1,25(OH)2D] and in renal production of 1,25(OH)2D. In nondiabetic animals, renal 1,25(OH)2D production is markedly stimulated by parathyroid hormone (PTH) and calcitonin (CT). There is evidence that diabetes impairs the responsiveness of the kidney to PTH. The effect of diabetes on responsiveness to CT is unknown. The studies reported here determined the effect of streptozotocin-induced diabetes on renal responsiveness to PTH and CT. Experiments were performed in 7- to 8-week-old rats that were fed a diet sufficient in calcium and vitamin D and were thyroparathyroidectomized (TPTX) 5 days before hormone treatment. PTH (0.33 U/g body weight at 24, 12, and 2 hours before death) significantly increased renal 1,25(OH)2D production by threefold in nondiabetic rats. This effect was markedly attenuated by diabetes. On the other hand, CT (20 U/100 g body weight at 12 and 2 hours before death) produced a maximal response in both groups of animals. In diabetic rats, CT stimulated renal 1,25(OH)2D production fivefold, whereas PTH stimulated production only 1.5-fold. Diabetes did not affect the capacity of PTH to increase serum calcium or decrease renal tubular reabsorption of phosphorus (TRP). These findings suggest that the decrease in renal 1,25(OH)2D production seen in experimental diabetes may be due to decreased renal responsiveness to PTH, but not to decreased responsiveness to CT.
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PMID:Calcitonin stimulates 1,25-dihydroxyvitamin D production in diabetic rat kidney. 198 64

Islet amyloid polypeptide (IAPP) or amylin, a recently discovered minor secretory peptide of the beta-cell related to calcitonin gene-related peptide (CGRP), is a constituent of amyloid deposits in the islets of many non-insulin-dependent (type II) diabetic individuals and some elderly nondiabetic subjects. IAPP is synthesized as a small precursor at a level of approximately 1% that of insulin and is processed, amidated, stored in beta-granules, and released along with insulin and C-peptide. Analysis of its gene (located on chromosome 12) supports an evolutionary relationship to calcitonin and CGRP, peptides with which it shares some biological actions. Like CGRP, IAPP antagonizes the action of insulin mainly at the level of muscle glycogen synthesis, but the levels required for this effect seem to be considerably higher than reported circulating levels. No evidence for overproduction of IAPP in diabetic subjects has been found thus far, but much more work is necessary to define its normal secretory rates and clearance. Other proposed actions of IAPP include serum calcium-lowering effects and smooth muscle relaxation; the latter effect might promote the uptake of insulin into the circulation within the islets. Deposition of amyloid is species selective due to structural differences within the central part of the molecule and may be initiated intracellularly in type II diabetes by several mechanisms. No differences in the structure of IAPP or its precursor have been found in individuals with maturity-onset diabetes of the young or type II diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1991 Mar
PMID:Is islet amyloid polypeptide a significant factor in pathogenesis or pathophysiology of diabetes? 199 69

The effect of short-term and long-term streptozotocin-induced diabetes on the pattern of distribution and tissue content of adrenergic and peptidergic nerves in ileum and distal (descending) colon of the rat was examined using immunohistochemical, biochemical, and immunochemical techniques. The effect of short-term streptozotocin-induced diabetes on the level of noradrenaline compared with weight-restricted (starved) and untreated controls in the celiac (celiac-superior mesenteric ganglia complex) and inferior mesenteric ganglia, which supply the two regions of the intestine, was also compared. The pattern of change in the distribution of dopamine-beta-hydroxylase-, substance P-, calcitonin gene-related peptide-, and vasoactive intestinal polypeptide-like immunoreactive nerve fibres that was observed in the ileum from diabetic rats was not evident in the myenteric plexus of distal colon. In contrast to the ileum, there was no evidence of degenerative change in any of the nerve types investigated in the myenteric plexus of the distal colon. The level of vasoactive intestinal polypeptide in the diabetic rat ileum was significantly increased, whereas the level of noradrenaline was reduced; no such changes were observed in the distal colon. The tissue content of noradrenaline in the celiac ganglion, which projects to the ileum, was increased at 8-week diabetes compared with both weight-restricted and untreated controls, whereas the diabetic state had no effect on the levels of noradrenaline of the inferior mesenteric ganglion, which projects to the distal colon. It is concluded that there is a differential effect of streptozotocin-diabetes on different regions of the rat intestine. The adrenergic and peptidergic innervation of the distal colon were changed little compared with ileum. This may be explainable in terms of the different functional roles of these two regions of the intestine and/or by the difference in origin of the sympathetic nerves supplying the two regions of the intestine.
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PMID:Differential effect of streptozotocin-induced diabetes on the innervation of the ileum and distal colon. 200 99

The application of molecular biology to problems in diabetes mellitus has begun to reveal the underlying molecular defects contributing to the development of hyperglycemia. Islet amyloid represents the most common pathological lesion occurring in the islets of NIDDM subjects. The use of both biochemistry and molecular biology has lead to the identification of the major protein component of human islet amyloid and elucidation of the structure of its precursor. This protein, termed islet amyloid polypeptide, is related to two neuropeptides, calcitonin gene-related peptides 1 and 2, and represents a new beta-cell secretory product whose normal physiological function remains to be determined. The use of molecular biology has also led to a better understanding of the molecular defects contributing to insulin resistance. Characterization of the insulin-receptor gene in patients with extreme forms of insulin resistance has resulted in the identification of mutations that impair its function and lead to tissue resistance to the action of insulin. Molecular biological approaches have also led to a better understanding of the regulation of glucose transport. They have revealed that there is a family of structurally related proteins encoded by distinct genes and expressed in a tissue-specific manner that are responsible for the transport of glucose across the plasma membrane. Moreover, they have shown that specific depletion of the glucose-transporter isoform that mediates insulin-stimulated glucose transport is responsible for decreased transport activity in adipose tissue in insulin-resistant states.
Diabetes 1991 Apr
PMID:Lilly lecture 1990. Molecular defects in diabetes mellitus. 201 42

At present great attention is paid to Ca2+ metabolic derangement in the pathogenesis of cardiovascular alterations. Some researchers interpret this derangement as change in the ratio of parathyroid secretory activity and thyroid C-cell activity. For this purpose the blood levels of parathormone and calcitonin were investigated by radioimmunoassay with simultaneous recording of lower limb hemodynamic indices in 136 patients with diabetes mellitus. Change of elasticity of major vessels, a decrease in the reserve blood flow, marked to a greater extent in patients over 40 and combined with essential hypertension, were observed. An increase in the blood levels of parathormone and calcitonin was also observed. Direct correlation was established in both age groups between the levels of parathormone and calcitonin and hemodynamic indices.
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PMID:[Secretion of calcium-regulating hormones in diabetes mellitus]. 202 61

Both human and rat islet amyloid polypeptide with COOH-terminal amide (IAPP-NH2) dose-dependently displaced the specific binding of 125I-labeled [Tyr0] rat alpha-calcitonin gene-related peptide (CGRP) to rat liver plasma membranes, whereas human IAPP (IAPP-COOH) had no effect. Conversely, human or rat IAPP-NH2 but not human IAPP-COOH evoked dose-dependent activation of adenylate cyclase in the membranes, and these effects were significantly inhibited by the CGRP-receptor antagonist human CGRP-1(8-37). Moreover, the dose of human or rat IAPP-NH2 necessary for producing half-maximal activation of adenylate cyclase was comparable with that for producing a half-maximal inhibition of the label binding. Thus, IAPP-NH2 but not IAPP-COOH appears to induce adenylate cyclase activation via CGRP receptors on rat liver plasma membranes.
Diabetes 1990 Jul
PMID:Activation of adenylate cyclase by islet amyloid polypeptide with COOH-terminal amide via calcitonin gene-related peptide receptors on rat liver plasma membranes. 216 4

Islet amyloid polypeptide (IAPP), also known as amylin, has previously been demonstrated to occur in amyloid deposits in pancreatic islets in type 2 diabetics, and, therefore, the peptide has been suggested to be involved in the pathogenesis of diabetes. The 37 amino acid peptide shows approximately 50% homology with the intrapancreatic neuropeptide calcitonin gene-related peptide (CGRP), a peptide that inhibits insulin secretion. We therefore examined, in model experiments in mice and rats, if IAPP also exerts this effect. IAPP was given intravenously, at dose levels at which CGRP previously has been shown to inhibit insulin secretion. Thus, in mice, IAPP was injected at 0.85 and 4.25 nmol kg-1, and in rats IAPP was infused at 17 or 68 pmol min-1. However, neither basal nor glucose-stimulated insulin release was inhibited by IAPP under these experimental conditions. We also investigated if IAPP (10(-11) to 10(-6) M), when incubated in vitro with isolated, overnight-cultured rat islets, could affect insulin secretion induced by glucose (3.3, 8.3 or 11.7 mM). However, also in vitro no effect by IAPP on insulin release was observed. Hence, in mice and rats, IAPP does not inhibit insulin secretion under experimental conditions identical to those previously used to demonstrate an inhibition by CGRP. Therefore, we conclude (1) that the homologous amino acid sequence within IAPP and CGRP does not seem to be sufficient for inducing inhibition of insulin release in mice and rats and (2) that the possible involvement of IAPP in the pathogenesis of diabetes type 2 still remains speculative.
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PMID:Failure of islet amyloid polypeptide to inhibit basal and glucose-stimulated insulin secretion in model experiments in mice and rats. 218 42

Aging is characterized, besides other changes, by a progressive increase in calcium content in the arterial wall, which is enhanced by diabetes mellitus, osteoporosis, arterial hypertension, and tabagism. As to tabagism, experiments in animals have shown that nicotine can increase calcium content of the arterial wall, and clinical studies have demonstrated that cigarette smoking induces peripheral vasoconstriction, with consequent increase in blood pressure levels. In order to study the role of calcium ions in the pathogenesis of the vasoconstrictive lesions caused by "acute" smoking, the author has studied the peripheral vascular effects of the calcium-channel antagonist nifedipine, a dihydropyridine derivative, and calcitonin, a hypocalcemizing hormone which possess vasoactive actions on 12 elderly regular smokers (mean age 65.8 years). The results demonstrated that both nifedipine (10 mg sublingually 20 min before smoking) and salmon calcitonin (100 MRC U/daily intramuscularly for three days) are able to prevent peripheral vasoconstriction evaluated by Doppler velocimetry, as well as the increase of blood pressure induced by smoking. On the basis of our results, the author proposes that cigarette smoking-induced vasoconstriction is a calcium-mediated process, which can be hindered by drugs with calcium antagonist action.
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PMID:Smoking, calcium, calcium antagonists, and aging. 222 75


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