Immunoassay of Insulin: Two Antibody System: Plasma Insulin Levels of Normal, Subdiabetic and Diabetic Rats

Morgan, Carl R.; Lazarow, Arnold

doi:10.2337/diab.12.2.115

Cited by 2,176 publications

(548 citation statements)

References 7 publications

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“…Plasma glucose concentrations were measured using the glucose oxidase method. Immunoreactive insulin concentrations were measured in plasma by radioimmunoassay using a modification of a double antibody method [48]. Plasma leptin concentrations were also measured by radioimmunoassay (Linco Research, St. Louis Mo., USA) [49].…”

Section: Methodsmentioning

confidence: 99%

Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma lipoproteins: evidence for independent roles of age and sex

et al. 2003

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Aims/hypothesis. Increased intra-abdominal fat is associated with insulin resistance and an atherogenic lipoprotein profile. Circulating concentrations of adiponectin, an adipocyte-derived protein, are decreased with insulin resistance. We investigated the relationships between adiponectin and leptin, body fat distribution, insulin sensitivity and lipoproteins. Methods. We measured plasma adiponectin, leptin and lipid concentrations, intra-abdominal and subcutaneous fat areas by CT scan, and insulin sensitivity index (S I ) in 182 subjects (76 M/106F). Results. Adiponectin concentrations were higher in women than in men (7.4±2.9 vs 5.4±2.3 µg/ml, p<0.0001) as were leptin concentrations (19.1±13.7 vs 6.9±5.1 ng/ml, p<0.0001). Women were more insulin sensitive (S I : 6.8±3.9 vs 5.9±4.4×10 −5 min −1 /(pmol/l), p<0.01) and had more subcutaneous (240±133 vs 187±90 cm 2 , p<0.01), but less intra-abdominal fat (82±57 vs 124±68 cm 2 , p<0.0001). By simple regression, adiponectin was positively correlated with age (r=0.227, p<0.01) and S I (r=0.375, p<0.0001), and negatively correlated with BMI (r=−0.333, p<0.0001), subcutaneous (r=−0.168, p<0.05) and intra-abdominal fat (r=−0.35, p<0.0001). Adiponectin was negatively correlated with triglycerides (r=−0.281, p<0.001) and positively correlated with HDL cholesterol (r=0.605, p<0.0001) and Rf, a measure of LDL particle buoyancy (r=0.474, p<0.0001). By multiple regression analysis, adiponectin was related to age (p<0.0001), sex (p<0.005) and intra-abdominal fat (p<0.01). S I was related to intraabdominal fat (p<0.0001) and adiponectin (p<0.0005). Both intra-abdominal fat and adiponectin contributed independently to triglycerides, HDL cholesterol and Rf. Conclusion/interpretation. These data suggest that adiponectin concentrations are determined by intra-abdominal fat mass, with additional independent effects of age and sex. Adiponectin could link intra-abdominal fat with insulin resistance and an atherogenic lipoprotein profile. [Diabetologia (2003) 46:459-469] Keywords Adiponectin, Acrp30, adipoQ, central obesity, subcutaneous fat, intra-abdominal fat, insulin sensitivity, lipids, hepatic lipase, cardiovascular disease, leptin. It is well recognized that obesity and insulin resistance are closely related [1,2,3,4]. Android body fat distribution is associated with insulin resistance more than is a gynoid body fat distribution [5], with the site of abdominal fat distribution being an additional determinant of insulin sensitivity [6,7,8,9,10,11]. We found in both lean and obese subjects that the intraabdominal fat (IAF) depot is a stronger determinant of insulin sensitivity than the subcutaneous fat (SCF) depot [11], while SCF is the main determinant of the plasma concentration of leptin [11], an adipocyte-derived hormone regulating energy metabolism [12,13].

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Section: Methodsmentioning

confidence: 99%

Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma lipoproteins: evidence for independent roles of age and sex

et al. 2003

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“…Glycosylated haemoglobin was measured by boronate affinity chromatography with an intra-assay coefficient of variation of 4 % (BioRad, Hercules, Calif., USA). Serum insulin was assayed by a double antibody technique [23] with a lower limit of sensitivity of 20 pmol/l and an average intraassay coefficient of variation of 6 %. The cross reactivity of proinsulin in the radioimmunoassay for insulin is approximately 40 %.…”

Section: Methodsmentioning

confidence: 99%

Insulin secretory responses to rising and falling glucose concentrations are delayed in subjects with impaired glucose tolerance

et al. 2002

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Impaired glucose tolerance (IGT) is defined by an increase in plasma glucose in response to an oral glucose challenge to levels intermediate between normal and diabetic [1] and is a risk factor for the subsequent development of diabetes [2]. The transition from normal glucose tolerance to IGT is characterized by a reduction in the ability of the pancreatic beta cell to sustain its compensatory response to insulin resistance [3]. When compared to subjects with normal glucose tolerance, those with IGT have a blunted insulin secretory response to the rise in glucose during a rapidly sampled intravenous glucose tolerance test (IVGTT) and a shift to the right in the dose-response curve relating the plasma glucose concentration to the insulin secretion rate [4,5]. IGT is additionally Diabetologia (2002) Abstract Aims/hypothesis. We hypothesized that beta-cell responses to changes in glucose would not be normal in subjects with impaired glucose tolerance (IGT). Methods. Three groups of 6 subjects were studied: normal weight with normal glucose tolerance (control subjects); obese with normal glucose tolerance (Obese-NGT); and obese with IGT (Obese-IGT). All subjects had a graded glucose infusion protocol to increase (step-up) and then decrease (step-down) plasma glucose. We obtained average insulin-secretion rates (ISR) over the glucose range common to all three groups during step-up and step-down phases, minimal model indices of beta-cell function (φ b , φ d , φ s , T up , T down ), and insulin sensitivity (Si). Results. ISR differed significantly between step-up and -down phases only in Obese-IGT individuals. Basal (φ b ) and stimulated (φ d , φ s ) beta-cell sensitivity to glucose were similar in the three groups. Delays between glucose stimulus and beta-cell response during both step-up (T up ) and -down (T down ) phases were higher in Obese-IGT compared to Controls and Obese-NGT individuals. The product ISR Si (10 ±5´m in ±2 l) was lower in Obese-IGT compared to Controls, both during step-up (919 851 vs 3192 1185, p < 0.05) and step-down (1455 1203 vs 3625 691, p < 0.05) phases. Consistently, the product φ s Si (10 ±14´m in ±2´p mol ±1 l) was lower in Obese-IGT than in control subjects (27.6 25.4 vs 103.1 20.2, p < 0.05). Conclusion/interpretation. Subjects with IGT are not able to secrete insulin to compensate adequately for insulin resistance. They also show delays in the timing of the beta-cell response to glucose when glucose levels are either rising or falling. [Diabetologia (2002) 45:509±517]

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“…Blood plasma concentration of insulin was measured with a radioimmuno assay kit (no. PI-12K, Linco, MO; Morgan and Lazarow 1963).…”

Section: Laboratory Analysesmentioning

confidence: 99%

Colostrum and milk fatty acids of dairy cows as influenced by extruded linseed supplementation during the transition period

Santschi¹,

Wettstein²,

Leiber³

et al. 2009

Can. J. Anim. Sci.

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M. 2009. Colostrum and milk fatty acids of dairy cows as influenced by extruded linseed supplementation during the transition period. Can. J. Anim. Sci. 89: 383Á392. The effects of precalving fat sources on fatty acid (FA) profile of colostrum and milk and on metabolic parameters in early lactation were determined. Two fat supplements (target: 21% fat, DM basis) fed at 1.8 kg DM d (1 were compared: Control (C; containing fractionated palm oil rich in 16:0) and Linseed (L; containing extruded linseed, rich in 18:3n-3). Sixteen dry Holstein (n07) and Brown Swiss (n 09) cows were assigned to four groups receiving the supplements from 5 wk pre-to 4 wk post-calving in different sequences: CC, CL, LC and LL. Treatments did not affect metabolic parameters, milk yield or composition. Linseed supplementation increased proportions of 18:0, 18:1, 18:2 and 18:3 in colostrum and milk (except 18:1 for colostrum). The highest n-3 FA proportion was observed in milk of LL cows. For most 16 and 18 FA, a fast response occurred within the first week of lactation for cows that switched treatments over calving. Carry-over to milk of 18:3 and its biohydrogenation products from linseed fed precalving was low. Pre-calving feeding strategies to favour incorporation of these FA into early lactation milk were not successful, but the reasons for this failure remain unclear.

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Immunoassay of Insulin: Two Antibody System: Plasma Insulin Levels of Normal, Subdiabetic and Diabetic Rats

Cited by 2,176 publications

References 7 publications

Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma lipoproteins: evidence for independent roles of age and sex

Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma lipoproteins: evidence for independent roles of age and sex

Insulin secretory responses to rising and falling glucose concentrations are delayed in subjects with impaired glucose tolerance

Colostrum and milk fatty acids of dairy cows as influenced by extruded linseed supplementation during the transition period

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