Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: DrugBank:APRD00631 (Gel)
 14,881 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Values reported for serum C-peptide immunoreactivity in healthy individuals vary considerably. To assess factors that contribute to this finding, three human C-peptide assay systems were developed utilizing three distinct antisera that react differently with various C-peptide fragments. Preparations of natural pancreatic and synthetic human C-peptide standards were compared immunologically in these systems. The curves of the natural C-peptide and the synthetic preparations were not identical. The relative immunoreactivity of each standard varied, depending on the particular antiserum used. Serum C-peptide concentrations varied when measured in the different assay systems. Furthermore, the results of dilution and recovery tests and stability of the C-peptide during storage showed differences among the three assays. Gel filtration of serum indicated heterogeneity within the major C-peptide peak, and in addition, a smaller peak of lower molecular weight material was present in some samples. Although degradation of serum C-peptide may occur during storage, fragments of C-peptide may also be secreted or arise during in-vivo metabolism. Thus, the present studies indicate the need for careful standardization and checking of each particular assay system before its use in clinical studies.
Diabetes 1978
PMID:Heterogeneity of circulating human C-peptide. 7 14

The degradation of insulin by isolated rat liver cells has been studied. The phenomenon is time- and temperature-dependent. After sixty minutes' exposure to 1.5 times 10-6 cells/ml, about 50 per cent, 15 per cent, and less than 5 per cent of insulin at 1.5 muM. are degraded at 37 degrees C., 20 degrees, and 0 degrees C., respectively. The methods used to measure the hormone degradation effect the apparent Vmax. Higher values of Vmax are found when radioimmunoassay rather than precipitation by trichloracetic acid and absorption to talc is used. However, the apparent Km. (0.27 muM) is virtually the same with any of methods used. N-ethyl-maleimide and Trasylol are potent inhibitors, whereas GSH increases the hormone degradation. Proinsulin acts as competitive inhibitor (apparent Ki equals 0.35 muM.). Gel filtration patterns of incubation supernates suggest that several enzymatic systems may be operative in the degradation of insulin by the liver cells. Glutathione-insulin-transhydrogenase is suggested by the appearance of a component that has the same elution volume as the A chain, but the inhibitory effects of trasylol on insulin degradation, as well as qualitative and quantitative similarities with insulin proteases, suggest that a proteolytic similiarities with insulin proteases, suggest that a proteolytic mechanism is involved. The insulin-degrading system in isolated liver cells closely resembles that observed in purified liver plasma membranes and in the isolated perfused liver. Such similarities stress the possible significance of the degradation process in the regulation of insulin action. These studies are also important for the quantitative analysis of insulin interaction with its specific receptors in isolated liver cells.
Diabetes 1975 Jun
PMID:Degradation of insulin by isolated rat liver cells. 16 96

Many gastrointestinal structural and functional properties are known to be altered in diabetes. In this study, we investigated whether serum and tissue gastrin levels are abnormally altered in a strain of genetically diabetic mice (C57BL/KSJ). Both serum and antral gastrin concentration were found to be significantly increased 3.4- and 2-fold above normal values in diabetic mice fed ad libitum. The increase in tissue gastrin concentration is most probably due to an increase in both cellular gastrin content and G-cell number, since the latter property is increased 130% in diabetic animals. Pair feeding studies demonstrated that diabetes associated hyperphagia is not a major factor in inducing these endocrine changes, since antral and serum gastrin are still significantly elevated above normal in diabetic animals fed a restricted diet. G-cell number, however, is not significantly increased above normal values in pair fed diabetic mice. The peak serum gastrin concentration after a meal and the duration of postprandial hypergastrinemia are also significantly increased above normal in diabetic animals. Gel filtration chromatography studies indicate that the antral nucosae of normal and diabetic mice have identical molecular forms of the hormone. It is therefore concluded that antral and serum gastrin concentration are increased in genetically diabetic mice due to both dietary alterations and other, as yet undefined, factors specific for the disease, and that the resultant hypergastrinemia may contribute to some of the gastrointestinal alterations seen in diabetes.
 ...
PMID:Alterations in serum and antral gastrin levels in genetically diabetic mice. 49 15

"Single-peak," "single-component," and "monocomponent" insulins have been produced in an attempt to eliminate insulin antigenicity. Recently "single-peak insulin" has been shown to be antigenic. From animal experiments and preliminary human studies it has been claimed that monocomponent (MC) insulin is nonantigenic or only negligibly so. In this study the antigenicity of MC insulin was determined in two groups of diabetic patients. In group 1, seven patients treated with insulin for the first time were given MC insulin for seven to fifteen months. Four of the seven patients developed significant IgG insulin antibodies after four to ten months. In one patient the IgG insulin antibody concentration was high (8.51 mU./ml.). In two patients, IgG proinsulin-specific antibodies were detected. In group 2, fourteen patients with unstable diabetes, insulin allergy, or resistance were changed from conventional to MC insulin. Treatment with MC insulin did not decrease insulin requirement or improve diabetic control when assayed by the M factor. After seven to eleven months of therapy there was no significant fall in insulin antibodies except in two patients in whom corticosteroids had been administered simultaneously. These results differ significantly from those previously reported and could be interpreted as suggesting that insulin itself is antigenic. When the purity of the MC insulin was determined, significant contaminants could be demonstrated in all of ten separate batches of MC insulin. Gel chromatography, polyacrylamide gel electrophoresis, and proinsulin radioimmunoassay were used to identify the presence of nonconvertible insulin dimer, proinsulin, and monodesamido insulin in antigenically significant concentrations. The generation of IgG insulin antibodies in MC-insulin-treated patients cannot be interpreted as a true indication that insulin itself is antigenic. The problem of insulin antigenicity has not been resolved and will not be until a highly purified insulin is available. Unfortunately, the MC insulins do not meet these requirements.
Diabetes 1975 Jul
PMID:Antigenicity of "monocomponent" pork insulin in diabetic subjects. 117 4

Glycated hemoglobin (GHb), fructosamine and glycated albumin (GA) in hemolytic sera from cadavers were analyzed for the postmortem diagnosis of diabetes mellitus. The levels of GHb and fructosamine were determined by boronate affinity chromatography and colorimetry, respectively. Albumin fraction was isolated from the samples by Affi-Gel Blue affinity chromatography. The glycated and non-glycated molecules were separated by boronate affinity chromatography, and quantitated by bromcresol green method. Fructosamine could not be analyzed from highly hemolytic sera containing more than 10 g/l hemoglobin. In such samples, the levels of GHb and GA were deviated from the standard values, indicating their postmortem degradation. In less hemolytic samples, GA was as informative as GHb and fructosamine for the diagnosis of diabetes mellitus.
 ...
PMID:Analysis of glycated albumin in postmortem blood samples as the diagnostic parameters of diabetes mellitus. 140 16

The present study was designed to investigate whether microalbuminuria at the onset of diabetic nephropathy might be partially due to the glycation of serum albumin. It is postulated elsewhere (Ghiggeri et al., Proc. Eur. Dial. Transplant. Assoc. 21 (1984) 633-636) that the glycation of serum albumin and the subsequent cationization may induce microalbuminuria. To investigate whether a relationship exists between the amount of glycated albumin in its cationized form and the development, and progression of diabetic nephropathy, the urinary excretion of glycated albumin was studied in diabetic patients. The diabetic patients (type I and II diabetes) were divided into groups according to their albumin excretion rates: group I diabetics had a normal albumin excretion (n = 30, x = 4.2 mg/12 h); group II diabetes displayed microalbuminuria (n = 17, x = 38.6 mg/12 h); group III diabetics displayed macroalbuminuria (n = 21, x = 582.5 mg/12 h). The fraction of glycated albumin in serum (Glyco Gel Test Kit) was 0.032 in group I, 0.042 in group II, and 0.038 in group III, all these values were significantly higher than the value for the controls (0.014%; n = 17, 2 alpha = 0.001) as measured with the Glyco Gel Test Kit. The concentration of glycated albumin in the urine of the controls and group I was below the detection limit. Urine in group II contained only a glycated albumin fraction of 0.0002 of total albumin, and the fraction for group III was 0.0008. Isoelectric focussing (IEF) and chromato-focussing revealed native albumin with an isoelectric point of 4.7-4.9, and anionic glycated albumin with a pI of 3.0-4.2.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Glycation of serum albumin and its role in renal protein excretion and the development of diabetic nephropathy. 149 58

In a previous study (Frazier et al., 1990), it was demonstrated that two patients with type 1 (insulin-dependent) diabetes mellitus had antibodies in their serum which reacted with four 29 kDa pancreas-specific proteins on two-dimensional immunoblots. This paper reports on the purification and identification of these pancreatic proteins. The protein with the pI closest to pH7 was purified through the use of ammonium sulfate fractionation and ion-exchange chromatography. Gel filtration chromatography established that the protein's molecular weight was closer to 25 kDa. Amino acid composition and sequence analyses demonstrated homology between the protein and chymotrypsin. It is suggested that an abnormal regulation of chymotrypsin activity might be related to antibodies formed in some diabetic patients.
 ...
PMID:Chymotrypsin-reactive antibodies in insulin-dependent diabetes mellitus. 158 8

Specific binding of ADH by the membrane fraction of the kidney medulla was lower in the normal CBA mice than in mutant mice with nephrogenic diabetes. Gel filtration of the solubilized ADH receptors of mutants revealed the presence of an unidentified factor which caused cooperative binding of ADH. DEAE-chromatography revealed no difference between cytosolic cAMP receptors in normal and mutant animals. Assay of GTP-ase activity of the membrane fraction revealed that ADH increased this parameter in CBA mice but not in mutant animals. Cholera toxin significantly diminished membrane ATP-ase activity whereas membrane preparations from mutant mice developed a reactivity to ADH. GTP binding ability in these preparations was higher than inn intact ones. In CBA mice this ability increased dramatically. HPLC profiles of G-protein complexes with GNP were very different in CBA and mutant mice. Mutation seems to cause changes both in binding and in "cross-talk" link op-complex membrane receptor of ADH.
 ...
PMID:[ADH and cAMP receptor binding in the kidney medulla of mice insensitive to ADH]. 166 85

Immunoreactive (ir)-endothelin (ET) in urine was studied with a radioimmunoassay in patients with diabetes mellitus (DM) and non-DM diseases including endocrine disorders, primary glomerular diseases, autoimmune diseases, and hematological malignancies. Twenty-four-hour excretions (mean +/- SEM) of ir-ET were 8.0 +/- 0.9 pmol/day in the DM group (n = 13) and 9.5 +/- 1.2 pmol/day in the non-DM group (n = 51). No significant differences among DM and other disease groups were noted with respect to 24-h ir-ET excretion. Reverse-phase high-performance liquid chromatography of a normal urine extract revealed a major peak eluting later than ET-1. Gel chromatography revealed a single major peak in a smaller molecular weight (MW) region in normal urine and an additional peak in larger MW region in a urine extract from a DM patient. Urinary ir-ET consists of at least two components which may be metabolites of ET or ET precursors in plasma or peptides derived from the kidney.
 ...
PMID:Immunoreactive endothelin in urine of patients with and without diabetes mellitus. 172 99

A new active peptide was purified from the acid-alcohol extract of pork pancreas. It markedly suppressed the insulin activity detected by either in vivo mouse convulsion assay or in vitro free-fat cell assay. When the extract was subjected to chromatography on a carboxymethylcellulose column, the insulin fraction completely passed through the column, whereas the glucagon fraction was absorbed. The fact that the total apparent biological activity of insulin in the exclusive eluate was higher than in the original extract and the insulin radioimmunoactivity remained unchanged led to the discovery of a potent insulin inhibitor in the extract. The inhibitor was separated from glucagon and insulin in the extract by ion-exchange chromatography on a carboxymethylcellulose column followed by gel filtration on a Bio-Gel P-6 column and finally purified by reverse-phase high-performance liquid chromatography (HPLC) on a C-18 column. The antagonistic effect of this inhibitor on insulin was dose dependent with an ED50 of 2 x 10(-10) M, which was the same level used for insulin in vitro assay (1.7 x 10(-10) M). Amino acid analysis of the inhibitor showed that it was rich in arginine and glycine. It was estimated to be approximately 3000 Mr. The NH2-terminal of the peptide was proved to be blocked because it could not be degraded by Edman degradation. Based on the physicochemical and biochemical characteristics of the inhibitor and compared with other active peptides known to be in the pancreas, the inhibitor is probably a new active peptide that might play an important role in homeostasis of carbohydrate metabolism.
Diabetes 1991 Sep
PMID:Purification and preliminary characterization of new peptide inhibitor of insulin from pork pancreas. 193 26


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