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

A copper-containing amine oxidase is present in sheep blood plasma and has a high capacity to deaminate spermine and spermidine. The physiological function of this enzyme remains to be determined. Sheep blood plasma amine oxidase (SPAO) was measured by its ability to deaminate spermidine (700 microM) using a peroxidase-linked colorimetric assay developed for microtitre plates. SPAO activity has been studied in a group of Welsh Mountain sheep with experimental alloxan-induced diabetes. This resulted in an increase in SPAO activity which reached a peak of 70 days after alloxan treatment (60 per cent increase). This change could be seen in both pregnant and non-pregnant diabetic sheep. In normal pregnant ewes, SPAO activity remained stable for the first 100 days of pregnancy but declined by 50 per cent in the last month of pregnancy. Together, these findings suggest that SPAO activity is controlled by hormonal influences. This sensitive and convenient assay method could provide clues as to the physiological significance of SPAO and may be a useful clinical chemical indicator in the sheep.
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PMID:Physiological and pathological influences on sheep blood plasma amine oxidase: effect of pregnancy and experimental alloxan-induced diabetes mellitus. 188 42

The ingestion of fructose, particularly in refined form, has significantly increased in the North American diet over the last two decades. The unique way in which fructose is metabolized has given rise to much research examining whether fructose is advantageous in appetite control, exercise endurance, and disease states such as diabetes. Overall, there is very little evidence that modest amounts of fructose have detrimental effects on carbohydrate and lipid metabolism in nondiabetic or NIDDM subjects or that its use is particularly advantageous compared to that of other sugars. However, fructose can cause insulin and triglyceride levels to rise dramatically, and hence be potentially harmful, in a subgroup of NIDDM subjects who have concomitant pronounced hypertriglyceridemia. Large doses of fructose should also be avoided by subjects with gout because of the hyperuricemia which may result. No evidence exists that fructose has any clear advantages over glucose in regard to exercise endurance. Similarly there is no conclusive evidence that physiologic amounts of dietary fructose exacerbate copper deficiency or aid in weight control.
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PMID:Current issues in fructose metabolism. 189 98

Incubation of corneal collagen type I with glucose in the presence of transition metal ions (copper, iron) results in the formation of collagen aggregates insoluble in 6 M urea, and in 2% sodium dodecyl sulfate + 5% beta-mercaptoethanol. The reaction is mediated by hydrogen peroxide and transition metals since it is inhibited by catalase and by the chelating agent diethylenetriaminepentaacetic acid. Comparative studies showed that copper is more efficient than iron and that the reaction proceeds more rapidly with ribose than with glucose. The data support a mechanism involving transition metal ion catalyzed autoxidation of glucose (and possibly of Amadori products) with generation of superoxide radical. Superoxide dismutation produces hydrogen peroxide, which then generates hydroxyl radicals in the presence of transition metal ions (Fenton reaction). Hydroxyl radical attack is known to lead to cross-linking, which is enhanced in glycated proteins. The experimental data presented are consistent with in vivo alteration of collagen properties during normal aging and with the acceleration of similar changes in diabetes mellitus.
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PMID:The role of nonenzymatic glycosylation, transition metals, and free radicals in the formation of collagen aggregates. 189 43

The involvement of Zn2+ in the inhibitory action of insulin and phenformin on bulk proteolysis was studied in the Langendorff rat heart with a Zn(2+)-buffering perfusate (0.1 mM citrate, physiological complete amino acids and 0.2% albumin). Proteins were biosynthetically labeled in vitro for 10 min with [3H]leucine. Rapidly degraded proteins were eliminated during a 3-h preliminary degradation without insulin or added Zn2+ (2 mM nonradioactive leucine). Insulin (5 nM), the lysosomal inhibitor chloroquine (30 microM), and the biguanide antihyperglycemic agent phenformin (2 microns) each caused a sustained 35-40% inhibition of [3H]leucine release beginning within 1-2 min and reaching a maximum at 1-1.5 h. When these agents were combined, their simultaneous proteolytic inhibitory effects were not appreciably greater than the effect of chloroquine alone. Infusion of supraphysiological perfusate Zn2+ (greater than 15 microM) mimicked the inhibitory effect of insulin and chloroquine on lysosomal proteolysis. Infusion of supraphysiological Co2+, Mn2+, Fe2+, and Cr3+ (30 microM, 0.5 h) caused no change in proteolysis; however, 30 microM Cu2+ caused a slight inhibition. Presumptive chelation of the background (approximately 20 nM) Zn2+ by infusion of 3 microM CaNa2 EDTA caused no change in protein degradation over 1-2 h. The infusion of a physiological concentration of 1 or 5 microM Zn2+ (as ZnCl2) caused no change in protein degradation over 1-2 h. Biguanides are known to reversibly form a Zn2+ complex with affinity less than that of Zn2+ for EDTA. Prior infusion of 3 microM CaNa2 EDTA inactivated the proteolytic inhibitory effect of maximal (2 microM) phenformin over at least 1.25 h of concurrent infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1991 May
PMID:Effect of Zn2+ on the proteolytic inhibitory action of insulin and biguanide antihyperglycemic drugs. 190 28

Transition metal-catalysed oxidations have been implicated in the complications of diabetes. We report here that some experimental inhibitors of the enzyme aldose reductase (implicated in diabetes mellitus via its ability to catalyse glucose reduction to sorbitol) are also potent inhibitors of transition metal-catalysed ascorbate oxidation. The inhibition appears to be dependent upon the presence of a spirohydantoin group. It is conceivable that the copper- and iron-binding capacity of these compounds may contribute to some of their observed biological effects and may provide a starting point for a new generation of experimental drugs for the treatment of diabetes mellitus.
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PMID:Spirohydantoin inhibitors of aldose reductase inhibit iron- and copper-catalysed ascorbate oxidation in vitro. 190 28

The best methods of contraception for women with insulin-dependent diabetes mellitus and gestational diabetes are discussed, with results of clinical trials in both types of patients. Women with IDDM require effective contraception since there are serious risks both to the mother and the fetus in case of unplanned pregnancy. For women reliable enough to use them consistently, barrier methods are satisfactory. IUDs are the choice for most diabetic women. In a trial of copper-T 200 IUDs in 103 diabetics compared to 119 normal controls, the effectiveness, expulsion rate, removals for bleeding and pain, and continuation rates were comparable. It was noted that there were no added infections in the diabetic group, who have an increased risk for infection generally. Oral contraceptives may worsen glucose tolerance, due to the effect of the progestogen decreasing diabetes, except in women with history of gestational diabetes. The authors found that a triphasic pill, with lower progestin dose, decreased insulin sensitivity more than did a combined pill, in both normal women and in those with previous gestational diabetes. Since natural estrogens, as used in estrogen replacement therapy in climacteric women, do not affect glucose tolerance as much as synthetic alkylated estrogens (i.e., ethinyl estradiol), the authors tried a combination of 4 mg estradiol, 2 mg estriol and 3 mg norethisterone for contraception in diabetic women. This experimental combination was compared with a low dose ethinyl estradiol-norethisterone monophasic, a progestin only pill, and an ethinyl estradiol-levonorgestrel triphasic. There were no differences among the groups in fasting plasma glucose, 24-hour insulin requirements, HbA1C levels, LDL, or free fatty acids. VLDL and HDL cholesterol and total cholesterol decreased in the natural estrogen group. There was a small, significant increase in LDL, VLDL and total cholesterol in the combined group. The authors also have preliminary results of a trial of a low-dose monophasic with ethinyl estradiol and gestodene, showing no adverse effects on glycemic control in IDDM patients. Thus low dose progestin, triphasic and natural estrogen-progestagen combination oral contraceptives can be recommended as safe to diabetics.
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PMID:Contraception for women with diabetes: an update. 195 24

A brief analysis of copper metabolism demonstrates that coeruleoplasmine, an enzyme synthesized by the liver, contains approximately 90 p. cent of the serum copper. There are major alterations of copper metabolism during pregnancy. Copper and coeruleoplasmine concentrations increase from the sixth week, reaching particularly high levels during the third trimester before returning to normal six weeks after delivery. The copper concentration in the cord serum is much lower than that of the maternal plasma. The mechanism of this placenteal transfer is unknown. There is a reserve form of copper which is specific to the fetus and the newborn, represented by the neonatal mitochondrocupreine of the liver. Elevated levels of maternal serum copper would be the result of the mobilisation of copper stocked in the liver an other tissues. The copper needs would then be increased in order to restore the reserves. Since diabetes mellitus is a major cause of maternal and perinatal complications, the first results of the serum copper obtained, in Nantes, in diabetic insulin-dependent pregnant women, in the cord blood and in newborns, are presented. A review of the current knowledge of copper in the maternal milk concludes this study.
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PMID:[Copper in the normal and diabetic pregnancy and in the perinatal period]. 218 36

In this study, plasma levels of magnesium, calcium, zinc and copper were simultaneously determined in pregnancies complicated by either abortion, intrauterine growth retardation (IUGR), diabetes or EPH (edema, proteinuria, hypertension) gestosis. The levels of the four cations in non-pregnant women and in healthy, pregnant women were also determined. Compared with controls, a significant decrease in magnesium, with increase of the Ca/Mg ratio, was found in spontaneous abortions, but not when patients had a successful continuation of pregnancy. In EPH gestosis, total calcium was reduced, with a significant decrease of the plasma Ca/Mg ratio. A slight, but significant, increase in plasma zinc was observed in women affected by either diabetes or IUGR, probably as a result of reduced zinc uptake by the fetus. In addition, higher copper levels were found in the pathologies studied, with the exception of missed abortions. The possible role of an altered Ca/Mg ratio homeostasis in relation to gestational pathologies is discussed.
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PMID:Maternal plasma concentrations of magnesium, calcium, zinc and copper in normal and pathological pregnancies. 227 Apr 73

Exocrine pancreatic enzyme activities and mineral concentrations were measured in a newly developed congenic strain of corpulent rat (SHR/N-cp). Approximately 4- to 5-wk-old corpulent (cp/cp) and lean (+/?) male rats consumed a diet containing 54% carbohydrate as either cooked cornstarch or 27% cooked cornstarch and 27% fructose for 9.5 mo. After consuming the diet for 3 mo, corpulent rats were hyperinsulinemic, hyperlipidemic and exhibited glycosuria. After consuming the diet for 9.5 mo corpulent rats were twofold heavier and pancreatic weight was 77% that of their lean littermates. Corpulent rats that consumed starch exhibited lower total pancreatic protein with no significant change in total DNA and RNA. In the corpulent rat, both lipase- and chymotrypsinogen-specific activities and both the specific activities and the content of amylase or trypsinogen were lower than those of lean littermates. Fructose consumption resulted in lower pancreatic copper and iron concentrations, and zinc concentration was elevated in corpulent rats. This study suggests that the SHR/N-corpulent rat may be a useful model for studying exocrine pancreatic function in insulin-independent diabetes.
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PMID:Exocrine pancreatic enzyme activities and mineral concentrations in SHR/N-corpulent (cp) male rats. 245 79

A new rodent model, SHR/N-cp, for study of non-insulin-dependent diabetes mellitus (NIDDM) has recently been developed. The present study reports exocrine pancreatic enzyme activities and mineral concentrations in female corpulent (cp/cp) and lean (+/?) rats fed a diet containing carbohydrate as cooked corn starch or sucrose for 7 months to determine the potential of the model for studies of diet and pancreatic function in NIDDM. Although corpulent female rats weighed 2.5 times more than their lean littermates, they consumed less calories when expressed per 100 g body weight than lean rats. Corpulent rats had a significantly smaller relative pancreatic weight than lean rats (p less than 0.0001), but had greater total pancreatic DNA content and concentration (p less than 0.003) and higher pancreatic amylase (p less than 0.0001), lipase (p less than 0.0011), and chymotrypsinogen (p less than 0.0208) specific activities. Corpulent rats had a significantly lower pancreatic copper concentration than their lean littermates (p less than 0.0193). Corpulent rats consuming starch had a higher pancreatic iron concentration than all other experimental groups (p less than 0.05). The corpulent female rats were only mildly diabetic based upon serum and urine indices. The data suggest that the female SHR/N-corpulent rat may be a useful model for studying exocrine pancreatic function of mild cases of non-insulin-dependent diabetes.
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PMID:Enzyme-specific activities and mineral concentrations of the exocrine pancreas from female SHR/N-corpulent (cp) rats. 248 46


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