Insulin and insulin-like growth factor-1 (IGF-1) receptors were quantified in glycoprotein fractions prepared by wheat germ agglutinin-agarose affinity chromatography from skeletal muscle of several species of salmonid fish and carp. Insulin binding in fish skeletal muscle was lower than insulin binding found in rat. IGF-1-specific binding was two- to sixfold ...

A 60-year-old man referred because of hypoglycemic bouts was found to have insulin autoantibodies. Total plasma insulin was as high as 1.44 nmol/l. Both plasma free insulin and C-peptide were in the normal range. The indirect immunofluorescence technique showed positivity for antinuclear antibodies. The T-lymphocyte populations in the peripheral blood ...

The effects of dietary polyunsaturated fat on insulin-dependent gene expression of lipogenic enzymes and a possible mechanism for PUFA-mediated suppression of the gene expression have been investigated in rat livers. When diabetic rats were injected with insulin, the insulin dose-dependent induction of lipogenic enzyme mRNAs were markedly reduced with increasing ...

To determine the role of the insulin receptor overexpression in breast epithelial cell transformation, the 184B5 human breast epithelial cell line was transfected with human insulin receptor cDNA. In two cell lines transfected with and overexpressing human insulin receptors (IR) (223.8 and 184.5 ng IR/10(6) cells), but not in untransfected ...

Insulin action is subject to regulation at the level of the insulin receptor and at postreceptor levels. Starvation and diabetes are often associated with insulin resistance for glucose metabolism in various tissues. In muscle, fat, and liver, we examined whether changes in the functionality of the insulin receptor correlated with ...

Insulin and somatostatin reportedly affect pancreatic acinar cell function via specific receptor binding. Theoretically peri-insular levels depend on the islet-acinar portal system, but the actual hormone levels have never been demonstrated. Rat pancreata were perfused anterogradely or retrogradely with 125I-insulin, -somatostatin, or -glucagon (each, approximately equal to 10(-11) mol/l). Tracer ...

Photodynamic therapy has been applied quite extensively over the last few years, whereby the activation of photosensitizers by light causes the production of reactive oxygen species such as singlet oxygen, which is cytotoxic. The goal of this study was the enhancement of the photodynamic activity of photosensitizers through their delivery ...

Although vanadium is found abundantly in animal and plant kingdoms its biological effects are not clear. Vanadate compounds have been shown to normalize blood glucose levels in streptozotocin treated rats, enhance glucose oxidation and improve the sensitivity to insulin by enhanced receptor binding in rat adipocytes. The aim of the ...

We previously demonstrated that internalized insulin enters the cytoplasm before accumulating in nuclei of H35 rat hepatoma cells. This finding raises the possibility that insulin may interact with cytosolic proteins in addition to insulin-degrading enzyme (IDE). In the present study, cytosol from H35 hepatoma cells, rat liver or muscle was ...

Oral administration of insulin incorporated into the wall of isobutylcyanoacrylate nanocapsule to diabetic rats induces a long-lasting normalization of their fasting glycaemia. In this study, we examined the biological action of encapsulated insulin on DNA and glycogen syntheses in Chinese hamster ovary cells transfected with the human insulin receptor gene. ...

Insulin resistance represents a situation with a high risk of atherothrombosis and is accompanied by increased plasma plasminogen activator inhibitor-1 (PAI-1) levels. Fasting insulin level is highly correlated with PAI-1 levels in plasma. It has been shown that insulin increases PAI-1 synthesis by the human hepatoma cell line Hep G2. ...

Phagocytosis and respiratory burst activity were measured by flow cytometry in fresh and cryopreserved human monocytes, after ingestion of Escherichia coli and Staphylococcus aureus. Mononuclear leukocytes, isolated from 15 healthy donors, were divided into two portions, of which one was examined immediately and the other was cryopreserved for 3 weeks. ...

The tissue sensitivity to insulin was evaluated using the hyperinsulinemic euglycemic clamp technique in a 44-year old male with Werner's syndrome associated with diabetes mellitus. In addition, the autophosphorylation of insulin receptors and the number of autophosphorylated insulin receptors were measured in his erythrocytes by a new enzyme-linked immunosorbent assay. ...

The maximal capacity of low affinity ouabain binding sites in kidney medulla was found to be increased by 20 +/- 3.8% after 2 weeks, and by 35 +/- 4.5% in 4 weeks diabetes. However, in kidney cortex no similar changes could be detected. Western blot analysis of Na+/K(+)-ATPase subunits in ...

We analyzed the structural correlates underlying the insulin-dependent selection of the specific anti-insulin IgG1 kappa mAb13-producing cell clone, derived from a patient with insulin-dependent diabetes mellitus treated with recombinant human insulin. First, we cloned the germ-line genes that putatively gave rise to the expressed VH and V kappa segments and ...

The effects of high glucose on insulin-receptor tyrosine kinase activity and gene expression were investigated in 3T3-HIR cells. Cells incubated for 48 h in the presence of 25 mM glucose showed a 5-fold increase in the amount of insulin receptors per cell, receptor autophosphorylation and phosphorylation of the exogenous substrate ...

That vanadium compounds act in an insulin-mimetic fashion both in vitro and in vivo has been well established. Both inorganic and organic vanadium compounds have been shown to lower plasma glucose levels, increase peripheral glucose uptake, improve insulin sensitivity, decrease plasma lipid levels, and normalize liver enzyme activities in a ...

Microphotohemolysis is a new technique that has been used to determine the presence of alterations in the erythrocyte membrane. The method involves light activation through a microscope of a fluorescent dye-erythrocyte-buffer solution in a hemocytometer. The interaction of the light and dye result in the generation of toxic oxygen products ...

Data presented here show that there are significant differences in the insulin binding affinity and the tyrosine kinase activity of the insulin proreceptor isoforms which contain or lack exon 11. The exon 11(+) proreceptor does not show significant variations from the mature processed insulin receptor and has only a 3- ...

Glucocorticoids stimulate, while insulin inhibits, the hepatic transcription of insulin-like growth factor-binding protein-1 (IGFBP-1). In the present studies, human HEP G2 hepatoma cells were transiently transfected with human (h)IGFBP-1 promoter constructs. Activity of a construct containing the first 1205 base pairs (bp) of the hIGFBP-1 promoter was stimulated 6-9.5-fold by ...

In order to shed light on the possible beneficial effect of dietary unsaturated fatty acids on insulin binding, the effect of fish oil and olive oil administration on insulin binding, autophosphorylation and tyrosine kinase activity of partially purified liver insulin receptors were investigated. These data were confronted with the parameters ...

Gold-labeled insulin is bound first of all to the cilia of the oral field of Tetrahymena. A primary treatment (hormonal imprinting) with insulin increases the binding capacity even after 24h and makes it more sensitive for appearance a week later, within a minute of giving insulin-gold. The food vacuoles contain ...

A cell surface adsorption isotherm approach is investigated with normal and diabetic (streptozotocin-induced) rat hepatocytes utilizing mathematical modeling. Freshly prepared monodispersed viable rat hepatocytes in Ca(2+)- and Mg(2+)-free phosphate buffer are obtained by collagenase perfusion and used in this study. [3H]ouabain is used as a ligand that specifically binds with ...

Chicken renal insulin receptors have been recently characterized; their number and kinase activities vary in response to altered nutritional status. In the present study, the effect of chronic corticosterone treatment was examined in 5-week-old chickens. The development of an insulin resistance following corticosterone was suggested after 1 and 2 weeks ...

We studied a woman with acanthosis nigricans and insulin resistance. The patient's Epstein-Barr virus-transformed lymphocytes revealed slightly decreased insulin binding and markedly decreased insulin-stimulated autophosphorylation of the insulin receptor. The nucleotide sequence analysis of the patient's genomic DNA revealed a 3-basepair in-frame deletion in one allele, resulting in the loss ...

Leprechaunism is a syndrome of severe insulin resistance. In general, mutations in both alleles of the insulin receptor are required for developing the leprechaun phenotype. Recently, we described a leprechaun patient having an Arg for Gly substitution in one allele of the insulin receptor whereas the other allele has the ...

The binding of 125I-insulin to primary cultures of bovine brain microvessel endothelial cells was examined. Insulin binding was both time and temperature dependent and inhibited by excess unlabeled insulin. Furthermore, the specific binding of insulin was polarized to the apical side of the cell monolayers. Upon binding, the labeled insulin ...

The effect of diabetes on insulin receptor processing was assessed in rat hepatocytes, 2-4 weeks after the induction of diabetes with streptozotocin. Isolated hepatocytes from control and diabetic rats were labelled for 30 min with [35S]methionine in methionine-free medium and chased with complete medium for 1-3 hrs. Solubilized cell extracts ...

The effects of insulin titres on regulation of receptor binding were studied in several fish species. Insulin receptors were semi-purified by affinity chromatography (WGA-agarose) from skeletal muscle of carp, brown trout and rainbow trout that had been subjected to increases in insulinemia produced either by arginine injection, food administration, or ...

The recent development of molecular biology enables us to identify three abnormal insulins (insulin Chicago, insulin Los Angeles and insulin Wakayama). In Japan, three pedigrees in which affected individuals secrete [LeuA3] insulin (insulin Wakayama) have been identified. In each family, hyperinsulinemia associated with an abnormally elevated insulin to C-peptide molar ...

The human insulin receptor has two isoforms derived from alternative splicing of exon 11 of the insulin receptor gene. The type B (containing exon 11, or exon 11+) isoform binds insulin with twofold lower affinity than the type A (lacking exon 11, or exon 11-) isoform. In efforts to resolve ...

To investigate the expression and subcellular distribution of insulin receptor substrate-1 in hepatocytes, which are major targets of insulin along with muscle and adipose tissue, we obtained monoclonal antibodies by immunizing mice with a fusion protein consisting of the C-terminal portion of the human insulin receptor substrate-1 and glutathione-S-transferase. Two ...

The binding of insulin to cultured IM-9 human lymphocytes was studied by flow cytometry using FITC-insulin and biotinylated insulins coupled to streptavidin-phycoerythrin (N alpha beta 1-biotinylinsulin (B-insulin) and N alpha B1-(biotinyl-epsilon-aminocaproyl)insulin (NBC-insulin)). The reference methods were 125I-insulin binding and the insulin-antiinsulin antibody complexes for flow cytometry. There was a close ...

The effects of 7 covalently dimerized insulin derivatives on glucose transport in differentiated 3T3-L1 cells were investigated. Symmetric cross-linkage at lysine B29 with a bridge of 2 (oxalyl), 8 (suberoyl) or 12 (dodecanedioyl) carbon atoms produced derivatives with essentially unaltered receptor binding affinity but largely reduced intrinsic activity. Regardless of ...

A single class of high affinity endothelin-1 (ET-1) binding sites with an apparent Kd of 350 pM and a binding capacity of 69,000 sites/cell was found in isolated rat adipocytes. Whereas ET-1 had no effect on basal glucose uptake, it inhibited insulin-stimulated glucose uptake in both a dose- and time-dependent ...

Specific insulin binding by the fetal lung insulin receptor is reduced in vitro by a combination of high glucose and insulin. Using 19-22 day fetal rat lung, we studied the effect of culture for 48 hours under conditions of low (10mM) and high (100mM) glucose with and without added insulin ...

The beta-subunit of the insulin receptor from the muscle of the shrimp Penaeus japonicus exists as multiple subtypes with M(r) of 79,000, 77,000 and 75,000. Only the subunit of M(r) 79,000 is autophosphorylated after the addition of insulin. The autophosphorylation occurred specifically at Tyr residues, as demonstrated by the specific ...

We have examined insulin binding, and insulin receptor associated tyrosine kinase activity in detergent solubilized and Ricin II-agarose purified receptor preparations from erythrocytes of obese and non-obese subjects with normal glucose tolerance and non-obese patients with NIDDM. Insulin receptor activity, as assessed by [125I Tyr A14] insulin binding, was significantly ...

The minimal promoter/transcription factor requirements for induction of phosphoenolpyruvate carboxykinase (PEPCK) transcription by cAMP-activated protein kinase A (PKA) and inhibition of this induction by insulin were investigated. H4 hepatoma cells were treated with or without insulin following cotransfection with chloramphenicol acetyltransferase reporter genes and expression vectors coding for the cAMP ...

The explanation of the mechanism of the response to gravity changes is of great importance for the determination of the capacity of human subjects to adapt to the load of gravitational stress. Therefore several studies were performed to investigate the activity of endocrine system, since the hormones are involved in ...

To clarify the mechanism of glucose intolerance induced by FK506, a novel immunosuppressant, 5 or 10 mg/kg/day of FK506 was dosed orally to rats for 2 weeks, and 125I-insulin binding to the erythrocytes, plasma glucose and insulin levels, and pancreatic insulin content were examined. Insulin binding to the erythrocytes of ...

Hepatic expression of insulin-like growth factor binding protein-1 is regulated by insulin and glucocorticoids. To study underlying mechanisms, rat hepatocytes in primary culture were transfected with deletion mutants and heterologous promoter constructs, identifying a 41 bp region of the rat insulin-like growth factor binding protein-1 promoter which is sufficient to ...

Isolated adipocytes from rats submitted to four weeks of ad libitum feeding (AL) or meal feeding (MF, 2 h/22 h, feeding/fasting, meal time: 8:00-10:00 a.m.) schedules or pre-incubated with or without melatonin (0, 1 nM, 10 nM, 100 nM) for 5 h were submitted to insulin-stimulated [3H]-2-deoxyglucose (0.1 mM, 0.12 ...

Insulin resistant states are characterized by receptor and post-receptor defects in insulin action. When the insulin resistant state progresses, elevated levels of insulin are accompanied by increasing levels of glucose. In a previous paper we demonstrated that treatment of isolated adipocytes with high levels of insulin led to a decrease ...

The insulin receptor was evaluated at different disease stages in the sand rat (Psammomys obesus), a model for nutrition-induced diabetes. Nondiabetic sand rats showed markedly low receptor number in liver compared with albino rats. Their receptor had an intact tyrosine kinase activity but a higher Km for ATP in the ...

A novel pathway for physiological "cross-talk" between the insulin receptor and the regulatory Gi-protein has been demonstrated. We tested the hypothesis that a coupling defect between Gi and the insulin receptor is present in the liver of obese patients with and without type II diabetes. Insulin 1 x 10(-9) M ...

Troglitazone (CS045), a compound belonging to the thiazolidine diones, is being tested as a new oral antidiabetic agent. Evidence exists from animal studies and clinical trials with non-insulin-dependent diabetes mellitus patients that Troglitazone might reduce insulin resistance. The molecular mechanism of this effect is not understood. In this study, we ...

Patients with insulin-dependent diabetes who receive pancreas/kidney transplants lose their need for insulin injections, but they become hyperinsulinemic and insulin resistant, and sometimes develop noninsulin-dependent diabetes mellitus. The reason for the insulin resistance is not well understood. Specifically, it is not known whether they become resistant to the action of ...

The change in transmembrane potential of rat adipocytes was measured using the fluorescent probe 3,3'-diethylthiadicarbocyanine iodide, diS-C2-(5). The method was calibrated by altering the potassium ion concentration while keeping the sum of potassium and sodium ions at a constant concentration of 153 mM (Bailey et al: Bioelectrochem. Bioenergetics 21:333-42, 1989). ...

Human insulin receptor RNA is expressed in two alternatively spliced forms (Ex. 11- and Ex. 11+) encoding protein isoforms with discrete functional differences. In vivo, the splicing varies between tissues and changes concomitantly with the control of glucose homeostasis. Recently, dexamethasone has been described to increase the relative expression of ...