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

The synthesis of glomerular basement membrane (GBM) total protein and collagen was assessed by two methods in vivo in normal and streptozotocin diabetic rats 4-6 weeks and 42-44 weeks after onset of hyperglycaemia, using L-[2, 3, 3H] proline as a radioactive precursor. The incorporation of tritiated proline into GBM hydroxyproline was used as a measure of collagen synthesis and that into proline as total protein synthesis. The basement membrane fractions from both short- and long-term diabetic rats attained much higher proline and hydroxyproline specific activities compared to normal GBM proline and hydroxyproline specific activities. Early insulin therapy with normalization of blood sugar levels in short-term (4-6 weeks) diabetic rats returned the abnormal increases in GBM total protein and collagen synthesis to normal. By contrast, poor glycaemic control with insulin did not prevent the increases in GBM protein synthesis. The results of the present study suggest that overall enhancement of GBM protein synthesis occurs in both short- and long-term streptozotocin diabetes. Early insulin therapy with normalization of blood sugar levels prevents this increase in GBM protein synthesis. Poor glycaemic control had no effect on abnormal GBM protein synthesis. This may be of potential significance in view of preventing chronic diabetic microvascular complications such as nephropathy.
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PMID:Metabolism of glomerular basement membrane in short- and long-term streptozotocin diabetic rats. 243 51

This study measured the velocity of the fast anterograde axonal transport of [3H]-proline-labelled proteins in sciatic motoneurones of rats with streptozotocin diabetes of 12 weeks duration and in age matched controls. Four groups of diabetic animals were studied. One of these groups remained untreated whilst 2 diabetic groups received a long-acting insulin twice weekly to limit body wasting, but to permit regular hyperglycaemia. One insulin-treated group and one other diabetic group received an aldose reductase inhibitor, "Statil" (ICI 128436) by dietary admixture. Neither diabetes alone nor any of the treatment regimes produced any significant alteration of axonal transport velocity. Sciatic nerve temperature was measured concomitantly. A slight nerve hypothermia was seen in the untreated diabetic rats, but not in either insulin-treated group. It is concluded that 2 aspects of diabetes mellitus, namely persistent hyperglycaemia and polyol pathway activity in nervous tissue are without effect on the velocity of fast orthograde axonal transport of proteins.
Diabetes Res 1986 Nov
PMID:Fast anterograde axonal transport in wasted and non-wasted diabetic rats; effects of aldose reductase inhibition. 243 44

We studied lungs of spontaneously diabetic Bio-Breeding/Worcester (BB/W) Wistar rats which resemble human insulin-dependent diabetes mellitus. Compared with the age-matched control group, the body weight of the diabetic rats tended to be smaller and lung wet and dry weight were similar, but lung dry weight, relative to body weight and to lung wet weight, was significantly larger. Both air and saline lung volumes were reduced in the diabetic rats, and volume-pressure (V-P) curves expressed as a percent of maximal lung volume were significantly shifted downward and to the right of those in the control group over the midportion. Total DNA and RNA contents were similar in both groups, whereas protein content and concentration and protein/DNA and RNA/DNA ratios were significantly reduced in the diabetic rats. In contrast, content and concentration of 4-hydroxy-L-proline, elastin, and crude connective tissue were significantly higher in the diabetic group. We conclude that the increase in connective tissue proteins in the BB/W rats is most likely responsible for the shift in the V-P curves.
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PMID:Lung mechanics and connective tissue proteins in diabetic Bio-Breeding/Worcester Wistar rats. 243 83

Skeletal abnormalities commonly reported in both human and experimental diabetes include impaired linear growth and osteopenia. In the present study we examined the effect of diabetes and insulin therapy on collagen, the major protein constituent of extracellular matrix. Insulin-deficient diabetes was induced in growing rats by injection of 90 mg/kg of streptozotocin. Articular cartilage and long bone (femur) were removed, and tissues incubated with [3H]-proline in vitro for 2 hours at 37 degrees C. Uptake of [3H]-proline into both collagen and noncollagen proteins was determined using purified bacterial collagenase. In cartilage, collagen production decreased to 46% of buffer-injected control animals within one week of induction of diabetes (p less than 0.01), and remained at this level for three weeks. A similar degree of suppression was found in long bone from untreated animals, in which collagen production decreased to 58% of control (p less than 0.01). Insulin administration at the onset of diabetes prevented the expected decrease in collagen production such that after one week of therapy, collagen production in bone and cartilage was 98% and 93% of control (p +/- 0.01 vs. untreated), respectively. When insulin therapy was delayed for one week after the induction of diabetes, collagen production in articular cartilage increased from 46% to 92% and 97% of control at the end of one and two weeks of therapy (p less than 0.01 vs. untreated), respectively. Noncollagen protein production in untreated rats decreased to 49% of control in long bone and to 72% of control in articular cartilage after one week (p less than 0.01), with correction to control levels in both tissues within one week of insulin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Correction of altered collagen metabolism in diabetic animals with insulin therapy. 267 27

Although changes in collagen production probably play a major role in the connective tissue defects of diabetes, we do not know to what extent these changes are attributable to hormonal/metabolic versus nutritional alterations. To study collagen production as influenced separately by nutrition versus hormonal/metabolic factors, rats were given 50 mg/kg i.v. streptozocin (STZ) (mild weight-gaining diabetes) or 100 mg/kg STZ (severe weight-losing diabetes) and compared with nondiabetic food-restricted rats to match weight changes in diabetic animals. Articular cartilage was incubated with [3H]proline, and uptake of [3H]proline into both collagen and noncollagen proteins was determined with purified bacterial collagenase. Collagen decreased to 49% in mildly diabetic rats and 16% in severely diabetic rats, compared with control rats fed ad libitum and decreased to 85 and 73%, respectively, in food-restricted rats (both P less than .01 vs. diabetes). Diabetes induced a greater defect in collagen production than food restriction and a greater decrease in collagen than noncollagen protein production within each group, suggesting a specific effect on collagen. With comparable levels of metabolic severity (glucose, beta-hydroxybutyrate), diabetic animals that lost weight produced significantly less collagen than animals that gained weight, suggesting separate mechanisms. Quantitation of the impact of undernutrition on collagen production in diabetes demonstrated that approximately 31 to 32% of the defect was due to undernutrition, leaving approximately 68-69% of the defect due to the diabetic state.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1989 Jun
PMID:Nutritional and hormonal regulation of articular collagen production in diabetic animals. 272 23

The formation of granulation tissue and collagen was studied in rats made diabetic with streptozotocin. Granulation tissue was harvested from the inside of steelmesh cylinders implanted in the back of diabetic and control animals. Four weeks after implantation there was a reduction in the quantity of granulation tissue and its collagen content in diabetic animals compared to controls. Rats with renal failure or malnutrition but no diabetes also formed less granulation tissue but in these animals the content of collagen in the granulation tissue was normal. These results suggest that the decrease of collagen, but not granulation tissue, in diabetes is a relatively specific phenomenon which was not due to the toxic effects of streptozotocin as the changes were prevented by insulin treatment. The hydroxyproline/proline ratio of diabetic collagen was found to be normal, excluding defective hydroxylation of proline as an important factor in the reduction of collagen in diabetes. Treatment with an aldose reductase inhibitor did not prevent the abnormalities of granulation tissue and collagen in diabetes, making it unlikely that increased activity of this enzyme played an important pathogenetic role. The observed reduction of granulation tissue mass and collagen content in diabetes may be important factors in the impairment of wound healing in diabetes.
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PMID:Abnormalities of granulation tissue and collagen formation in experimental diabetes, uraemia and malnutrition. 295 Nov 73

In vivo lung connective tissue and DNA synthesis, following intraperitoneal injection of [14C]proline and [3H]thymidine, were studied in streptozotocin-induced diabetic rats fed ad libitum. Insulin-treated diabetic and normal rats similarly fed, and undernourished rats weight-matched to the untreated diabetics, served as comparison groups. The ratio of unbound [14C]hydroxyproline to total [14C]hydroxyproline in the lung was used to assess connective tissue degradation. Compared to the normal group, the untreated diabetic animals showed similar synthesis of collagen and elastin, reduced synthesis of total protein and DNA, and decreased degradation of connective tissue. When compared with the normal group, the undernourished animals showed diminished synthesis of total protein, collagen, elastin, and DNA, and increased degradation of connective tissue. In comparison to the undernourished group, the untreated diabetic animals indicated increased synthesis of collagen and elastin, and diminished degradation of connective tissue; total protein and DNA syntheses were similar. The insulin-treated diabetic animals showed increased collagen and DNA synthesis. We conclude that experimental diabetes has a profound effect on lung connective tissue metabolism, supporting previous observations of connective tissue abnormalities and morphometric changes. The increase in lung collagen and elastin in diabetes is in part due to reduced breakdown of the connective tissue proteins.
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PMID:Experimental diabetes and the lung. II. In vivo connective tissue metabolism. 305 60

The purpose of this investigation was to collect data concerning changes in carbohydrate and amino acid metabolism following different surgical operations (thoracotomies, laparotomies). Blood of 20 metabolically healthy adult surgical patients, who had to undergo elective surgery (lobectomies, pneumonectomies, colon resections) was examined preoperatively, immediately postoperatively and from 1.-4.postoperative day. The experimental data during the perioperative phase showed a similar pattern in both groups of patients: We found a significant elevation in the blood glucose level and there was also a rise in plasma cortisol and plasma free fatty acids levels. We found no significant changes of blood lactate, plasma insulin and branched chain amino acids. Simultaneously we found a drop in plasma albumin, pre-albumin and some glucoplastic amino acids (ALA, GLN, THR, PRO). It is concluded that major abdominal and thoracic surgery give rise to a nonspecific stress situation reflected in carbohydrate and amino acid metabolism with the following metabolic symptoms: Raised lipolysis and gluconeogenesis, disturbance of glucose utilisation and obvious peripheral insulin resistance. These perioperative metabolic effects show some similarities to the metabolic situation in diabetes mellitus type 2.
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PMID:[Postaggression metabolism following laparotomy and thoracotomy]. 328 Feb 68

Diabetes mellitus is associated with a generalized defect in connective tissue metabolism, including decreased growth, poor wound healing, and osteopenia. To determine the role of circulating factors in the etiology of these defects, we studied the effects of diabetic rat serum (DRS) on collagen, the major protein component of connective tissues. After preincubation of costal cartilage from hypophysectomized rats with experimental serum for 20 hours, [3H] proline was added for final four hours of incubation. Collagen and noncollagen protein were quantitated using purified bacterial collagenase. Compared to incubation of tissue in buffer without added serum, collagen production in cartilage incubated with 2% DRS was decreased by 23% (P less than .05), and with 4% serum by 88% (P less than .01). In contrast, serum from normal rats (NRS) increased collagen to 158% above buffer-incubated cartilage at 1.0% (P less than .02) and to 196% at 2% serum (P less than .01). Noncollagen protein production decreased below buffer only after addition of 2% or more DRS and increased above buffer after addition of 2% or more of NRS (178%, P less than .05). Addition of insulin at 10 and 100 mU/mL to DRS did not reverse defective collagen production, and addition of glucose (up to 900 mg/dL) or ketones (20 mmol/L) to NRS did not induce the changes in collagen production seen after addition of diabetic serum. Chromatographic separation of serum revealed that the inhibitory activity of DRS was in the high molecular weight fraction (less than 5000).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Direct inhibition of collagen production in vitro by diabetic rat serum. 328 35

Degradation of glomerular basement membrane in diabetic and nondiabetic rats was measured by incubating isolated basement membrane with a homogenate of glomeruli obtained from metabolically healthy rats. When diabetic basement membrane was used, there was a marked decrease in the amount of collagen-typical (hydroxyproline, hydroxylysine, glycine) and noncollagen-typical amino acids (proline, lysine, leucine) released in the supernatant of the incubation assay. A negative correlation was found between the amount of collagen-typical amino acids released by diabetic basement membrane and the duration of diabetes. The results indicate that the collagenous and noncollagenous peptides of diabetic basement membrane are less susceptible to proteolytic degradation than those of nondiabetic controls. This may be due to increased nonenzymatic glycosylation of diabetic basement membrane.
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PMID:Degradation of glomerular basement membrane in diabetes. I. Susceptibility of diabetic and nondiabetic basement membrane to proteolytic degradation of isolated glomeruli. 332 39


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