A STUDY OF INSULIN RECEPTORS IN HUMAN MONONUCLEAR LEUCOCYTES

1976 ◽  
Vol 83 (3) ◽  
pp. 556-564 ◽  
Author(s):  
Oluf Pedersen ◽  
Henning Beck-Nielsen
Keyword(s):  
Silicone Oil ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Cell Number ◽  
Receptor Interaction ◽  
Specific Cell ◽  
Cell Binding ◽  
Temperature Dependent ◽  
Normal Body Weight ◽  
Mononuclear Leucocytes

ABSTRACT Insulin binding sites were demonstrated in human mononuclear leucocytes by use of a technique which includes isolation of mononuclear leucocytes from defibrinated blood and separation of cell bound and free [125I] insulin with silicone oil. The binding was time and temperature dependent. At 15°C equilibrium was reached after 90 min and a plateau maintained for at least 50 min. Incubations were carried out at 4°C, 15°C and 37°C. Maximal binding was obtained at 15°C. The optimum pH for insulin receptor interaction occurred at about 8. [125I] insulin binding to mononuclear leucocytes was demonstrated to be a linear function of cell number concentration over a range of 17–70× 106×ml−1. The binding was a displaceable function of native insulin concentration. In a group of 21 young healthy persons with normal body weight we found a mean specific cell binding fraction of 1.92 ± 0.58 (s) × 10−2. Analysis of the equilibrium between insulin and its receptor revealed an apparent heterogeneity of insulin receptors.

scholarly journals Guanosine nucleotides regulate hormone binding of insulin receptors

1992 ◽  
Vol 281 (3) ◽  
pp. 735-743 ◽  
Author(s):  
E R Mortensen ◽  
J Drachman ◽  
G Guidotti
Keyword(s):  
Binding Sites ◽  
Plasma Membranes ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Scatchard Analysis ◽  
Hormone Binding ◽  
Temperature Dependent ◽  
High Affinity ◽  
Mild Reduction ◽  
Adipocyte Plasma Membranes

Insulin receptors in turkey erythrocyte and rat adipocyte plasma membranes display non-linear hormone binding by Scatchard analysis. This result is consistent with evidence that the insulin-binding sites are heterogeneous and have at least two affinities for the hormone. Mild reduction of plasma membranes with dithiothreitol, before insulin binding, increased the fraction of hormone binding with high affinity without significantly changing the total number of receptor-binding sites. In the presence of guanosine 5′-[gamma-thio]triphosphate, the amount of receptor with high affinity for insulin in the reduced membranes decreased to that present in the absence of reduction; the effect of the nucleotide was concentration- and temperature-dependent. This decrease in insulin binding was specific for guanine nucleotides.

Insulin binding and action in adipocytes of pregnant rats: evidence that insulin resistance is caused by post-receptor binding defects

1984 ◽  
Vol 102 (2) ◽  
pp. 209-214 ◽  
Author(s):  
M. Th. Sutter-Dub ◽  
A. Sfaxi ◽  
F. Latrille ◽  
F. Sodoyez-Goffaux ◽  
J. C. Sodoyez
Keyword(s):  
Insulin Resistance ◽  
Biological Effect ◽  
Response Curve ◽  
Glucose Oxidation ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Receptor Interaction ◽  
Fat Cells ◽  
Pregnant Rats ◽  
Duration Of Pregnancy

ABSTRACT Insulin resistance was investigated in the adipose cell of rats which were at days 16 and 20 of pregnancy. Data are presented to relate insulin binding and biological effect, which was evaluated by the ability of insulin to stimulate [1-14C]glucose oxidation. Adipocytes from pregnant rats bound more insulin than fat cells from control (non-pregnant) animals and the number of insulin receptors per adipocyte increased during pregnancy. Basal glucose oxidation rate was decreased at 16 and 20 days of pregnancy: however, the dose–response curve for insulin-stimulated glucose oxidation was significantly depressed only after 20 days of pregnancy. The concentration at which insulin increased glucose oxidation by 50% increased with the duration of pregnancy. We conclude that during pregnancy in the rat the adipocyte response to insulin was decreased, despite an increase in insulin binding. This result suggests that a major determinant of insulin resistance in rat adipocytes during pregnancy is present after the initial insulin–receptor interaction. Consequently, a post-receptor defect may be largely responsible for the insulin resistance. J. Endocr. (1984) 102, 209–214

THE INSULIN RECEPTOR IN NORMAL AND OBESE PERSONS

1976 ◽  
Vol 83 (3) ◽  
pp. 565-575 ◽  
Author(s):  
Henning Beck-Nielsen ◽  
Oluf Pedersen ◽  
Jens Peder Bagger ◽  
Niels Schwartz Sørensen
Keyword(s):  
Plasma Insulin ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Fat Cell ◽  
Ideal Weight ◽  
Comparable Group ◽  
Significant Difference ◽  
Before And After ◽  
Obese Subjects ◽  
Mononuclear Leucocytes

ABSTRACT Using [125I]insulin at 172 pmol/l (1 ng/ml) the binding of insulin to mononuclear leucocytes isolated from peripheral blood was studied. Our present study comprised 21 healthy subjects (22–33 years old, 90–110% of ideal weight) and a comparable group of 22 obese subjects (20–37 years old, minimum 150% of ideal weight). A significant difference in insulin binding was found between the two groups, the mean specific insulin binding fraction in normals being 1.92 ± 0.58 (s) × 10−2 and that for the obese 1.19 ± 0.41 (s) × 10−2 (P < 0.01). No correlation was found between body weight and the number of insulin receptors in the obese subjects. However, the number of insulin receptors was negatively correlated to fat cell size (P < 0.05). Insulin receptors in subjects were also negatively correlated to fasting plasma insulin (P < 0.05). Insulin receptors were studied in 11 obese subjects before and after 10 days of fasting. A significant increase in the number of insulin receptors was observed with a simultaneous decrease in plasma insulin to normal values. The results indicate that obesity complicated by hyperinsulinism is associated with a decrease in the number of insulin receptors compared with the normal. This finding may in part explain the decreased insulin sensitivity of the hyperinsulinaemic obese.

scholarly journals Identification and characterization of insulin receptors on foetal-mouse brain-cortical cells

1984 ◽  
Vol 220 (1) ◽  
pp. 165-172 ◽  
Author(s):  
C F H Van Schravendijk ◽  
E L Hooghe-Peters ◽  
P De Meyts ◽  
D G Pipeleers
Keyword(s):  
Mouse Brain ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Cell Types ◽  
Receptor Interaction ◽  
Target Cells ◽  
Scatchard Analysis ◽  
Cortical Cells ◽  
Foetal Brain ◽  
Binding Cell

The occurrence of insulin receptors was investigated in freshly dissociated brain-cortical cells from mouse embryos. By analogy with classical insulin-binding cell types, binding of 125I-insulin to foetal brain-cortical cells was time- and pH-dependent, only partially reversible, and competed for by unlabelled insulin and closely related peptides. Desalanine-desasparagine-insulin, pig proinsulin, hagfish insulin and turkey insulin were respectively 2%, 4%, 2% and 200% as potent as bovine insulin in inhibiting 125I-insulin binding to brain-cortical cells, which corresponds to their relative biological potencies in classical insulin-target cells; no competition was observed with glucagon and nerve growth factor, even at high concentrations. Scatchard analysis of competitive-binding data resulted in curvilinear plots with a high-affinity binding of Ka = 3.6 X 10(8) M-1. Insulin binding to foetal brain-cortical cells differed, however, in two distinct aspects from that to classical insulin-binding cell types. Firstly, dilution of 125I-insulin-bound cells in the presence of unlabelled insulin did not accelerate dissociation of the labelled hormone. Secondly, exposure of brain-cortical cells to insulin before the binding assay enhanced insulin binding, suggesting up-regulation of insulin receptors in response to insulin. In conclusion, foetal-mouse brain-cortical cells bear specific binding sites for insulin. Their insulin receptor shows a marked specificity and affinity for insulin, but differs in at least two properties from most classical insulin receptors. These differences in hormone-receptor interaction could reflect structural differences between insulin receptors on embryonic and differentiated cells.

THE EFFECT OF FOOD INTAKE ON INSULIN RECEPTOR IN MAN

1979 ◽  
Vol 90 (3) ◽  
pp. 473-480 ◽  
Author(s):  
R. De Pirro ◽  
A. Bertoli ◽  
A. V. Greco ◽  
A. S. Gelli ◽  
R. Lauro
Keyword(s):  
Food Intake ◽  
Insulin Receptor ◽  
Normal Subjects ◽  
Insulin Binding ◽  
Specific Cell ◽  
Cell Binding ◽  
Metabolic Pattern ◽  
Receptor Affinity ◽  
Rapid Changes ◽  
Effect Of Food

ABSTRACT Insulin binding to circulating monocytes was studied in 22 normal volunteers before and 1, 3 and 5 h after a 1400 Kcal meal. Results indicate that 3 h after food intake there is an increase in the specific cell binding fraction (P < 0.001) with a change in receptor affinity. Data emerging from the present study demonstrate that there are rapid changes in insulin receptor properties during the day. These changes probably play a role in the regulation of the hormonal and metabolic pattern in normal subjects.

Colchicine Uptake and Binding by Human Platelets

1975 ◽  
Vol 34 (03) ◽  
pp. 780-794 ◽  
Author(s):  
Dianne M Kenney ◽  
Francis C Chao ◽  
James L Tullis ◽  
Gail S Conneely
Keyword(s):  
Time Dependence ◽  
Incubation Period ◽  
Binding Sites ◽  
Silicone Oil ◽  
Cold Treatment ◽  
Human Platelets ◽  
Temperature Dependent

SummaryThe uptake and binding of antimitotic alkaloid colchicine has been demonstrated in washed preparations of human platelets. A silicone oil technique was adapted so that both uptake and binding of 14C-colchicine were examined in the same platelet preparations. The time dependence and amount of colchicine taken up and bound by different platelet preparations during a 90 to 120 min incubation period were highly reproducible. Both colchicine uptake and binding by intact platelets, and colchicine binding by preparations of lysed platelets were specific and temperature dependent. Colchicine uptake was slowly reversible. Magnesium and GTP enhanced colchicine binding by lysed platelet preparations but calcium decreased binding.Exposure of platelets to either cold (4° C) or to thrombin, which disrupt platelet microtubules, produced significant increases in colchicine uptake and binding. The thrombin effect was maximal at 37° C and resulted in a greater increase in uptake and binding than that produced by either cold treatment alone or, by cold treatment followed by incubation with thrombin at 37° C. The amount of increase in uptake and binding produced by thrombin was independent of both thrombin (1–5 Units/109 platelets) and colchicine concentrations (1–50 × 10−6M).It is postulated that thrombin may initiate the formation, or make available, colchicine binding sites (microtubule subunits) within platelets.

Insulin and central regulation of spontaneous fattening and weight loss

1985 ◽  
Vol 249 (2) ◽  
pp. R203-R208
Author(s):  
R. B. Melnyk ◽  
J. M. Martin
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Weight Gain ◽  
Energy Balance ◽  
Binding Capacity ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Strong Positive Correlation ◽  
Central Regulation ◽  
Isolated Pancreatic Islets

Insulin binding to receptors in a partially purified hypothalamic membrane preparation is altered by prolonged starvation. To define further the relationship between hypothalamic insulin binding and energy balance, we studied the Richardson's ground squirrel, a hibernator that exhibits spontaneous 6- to 8-mo body weight cycles when kept in constant conditions. Isolated pancreatic islets from squirrels killed during the weight gain phase had greater glucose-stimulated insulin secretion than those from weight loss phase animals, and adipocytes showed significantly greater glucose incorporation into total lipid in response to insulin. Differences in lipogenesis were not attributable to changes in insulin-binding capacity. Hypothalamic tissue from weight gain phase animals bound more insulin than that from weight loss phase animals. Maximal binding was correlated with pancreatic islet responsiveness and maximal insulin-stimulated lipogenesis. The strong positive correlation between peripheral metabolic events associated with spontaneous alterations in energy balance and the binding kinetics of hypothalamic insulin receptors suggests that insulin may play an important role in the central regulation of body weight.

scholarly journals MECHANISM OF ACTION OF MIGRATION INHIBITORY FACTOR (MIF)

1972 ◽  
Vol 136 (3) ◽  
pp. 589-603 ◽  
Author(s):  
Richard W. Leu ◽  
A. L. W. F. Eddleston ◽  
John W. Hadden ◽  
Robert A. Good
Keyword(s):  
Alveolar Macrophage ◽  
Peritoneal Macrophage ◽  
Migration Inhibitory Factor ◽  
Immune Modulation ◽  
Peritoneal Macrophages ◽  
Cell Number ◽  
Inhibitory Factor ◽  
Cell Surface Receptor ◽  
Specific Cell ◽  
Surface Receptor

The initial interaction between migration inhibitory factor (MIF) and the guinea pig alveolar and peritoneal macrophage was studied. MIF-containing supernatants were generated from sensitized lymph node lymphocytes obtained from guinea pigs immunized with bovine gamma globulin in complete Freund's adjuvant. MIF-containing supernatants were markedly inhibitory for the migration of the peritoneal macrophage but had no effect on the alveolar macrophage. A linear relationship was observed between per cent inhibition of migration and serial twofold dilution of supernatant. Reexpressed in arbitrary MIF units, this relationship reflects a dose-response relationship with saturation characteristics. Pulse exposure of peritoneal macrophages to MIF resulted in adsorption of MIF onto both viable and nonviable cells with corresponding depletion of supernatant MIF. The alveolar macrophage did not adsorb MIF. Pulse adsorption of MIF onto the peritoneal macrophage is dependent on time, temperature, and cell number. Pretreatment of the cells with proteolytic enzyme prevents the adsorption of MIF while leaving migration unaffected. These observations support the existence of a specific cell surface receptor for MIF. The existence of such a receptor provides selectivity of immune modulation of macrophage populations by lymphocytes in delayed hypersensitivity reactions.

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