Heterogeneity of Crystalline Insulin1

Mirsky, I. Arthur; Kawamura, Kazunori; Riley, E.J.

doi:10.1210/endo-78-6-1115

Cited by 49 publications

(12 citation statements)

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“…1). One of the minor bands that migrates in front of the major component presumably represents desamido-insulin (32). The polyacrylamide gel pattern exhibited by this preparation of chicken insulin was intermediate between those of "monocomponent" porcine insulin and of a commercial preparation of porcine insulin that had been recrystallized 10 times (Fig.…”

Section: Physical and Chemical Characterization Of Chicken Insulinmentioning

confidence: 86%

Chicken Insulin: Radioimmunological Characterization and Enhanced Activity in Rat Fat Cells and Liver Plasma Membranes

1974

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Insulin was extracted from chicken pancreases and purified; its chemical, immunological and biological properties were investigated. The chicken insulin preparation appeared homogeneous on polyacrylamide gel electrophoresis and its amiho acid composition was similar to that previously described by others. Among 21 guinea pig antihuman, anti-bovine and anti-porcine insulin sera, only one anti-porcine and two anti-human insulin sera cross-reacted with chicken insulin to a large extent. With one of them, chicken and human insulins were equipoterit, on a weight basis, in competing with the binding of 131 I-human insulin. The use of 13l I-chicken insulin improved the sensitivity of the radioimmunoassay (0.02 ng of insulin/ml of incubation medium) and allowed measurement of chicken insulin within the physiological range of its plasma concentrations. Chicken insulin (40 fig/kg of body wt) lowered the blood glucose level by 25% in the chicken. In isolated rat fat cells, chicken insulin was 1.5-to 1.9-fold as potent as highly purified preparations of porcine insulin (27 IU/mg) in stimulating glucose oxidation. In rat liver plasma membranes, chicken insulin was 1.8->to 2.4-fold as potent as porcine insulin in competing with the binding of 125 I-porcine insulin, and 2.4-fold as potent as porcine insulin in competing with the binding of 125 I-chicken insulin to the insulin receptor sites. 125 I-chicken and l25 I-porcine insulins were degraded to the same extent by the .liver membranes. Therefore, the enhanced biological potency observed in the rat in vitro with chicken insulin can be entirely accounted for by an increased binding affinity for the insulin receptors. (Endocrinology 95: 1439(Endocrinology 95: , 1974

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Section: Physical and Chemical Characterization Of Chicken Insulinmentioning

confidence: 86%

Chicken Insulin: Radioimmunological Characterization and Enhanced Activity in Rat Fat Cells and Liver Plasma Membranes

1974

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“…However, improved analytical methods showed that crystallized insulin included proinsulin and intermediates, nonconvertible insulin dimers, arginyl and ethyl insulin, deamidated insulin, monodesamido insulin, and various noninsulin peptides (7)(8)(9). RIAs done in 1982 showed that twice-crystallized Novo monocomponent insulin contained proinsulin and its intermediates as well as trace amounts of other peptide hormones: proinsulin-like immunoreactivity up to 20,000 ppm, glucagon 45 ppm, pancreatic polypeptide 43 ppm, somatostatin 1.4 ppm, and vasoactive intestinal peptide 0.3 ppm (10).…”

Section: A Animal Insulin Preparationsmentioning

confidence: 99%

Immunological Responses to Exogenous Insulin

et al. 2007

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Regardless of purity and origin, therapeutic insulins continue to be immunogenic in humans. However, severe immunological complications occur rarely, and less severe events affect a small minority of patients. Insulin autoantibodies (IAAs) may be detectable in insulin-naive individuals who have a high likelihood of developing type 1 diabetes or in patients who have had viral disorders, have been treated with various drugs, or have autoimmune disorders or paraneoplastic syndromes. This suggests that under certain circumstances, immune tolerance to insulin can be overcome. Factors that can lead to more or less susceptibility to humoral responses to exogenous insulin include the recipient's immune response genes, age, the presence of sufficient circulating autologous insulin, and the site of insulin delivery. Little proof exists, however, that the development of insulin antibodies (IAs) to exogenous insulin therapy affects integrated glucose control, insulin dose requirements, and incidence of hypoglycemia, or contributes to beta-cell failure or to long-term complications of diabetes. Studies in which pregnant women with diabetes were monitored for glycemic control argue against a connection between IAs and fetal risk. Although studies have shown increased levels of immune complexes in patients with diabetic microangiopathic complications, these immune complexes often do not contain insulin or IAs, and insulin administration does not contribute to their formation. The majority of studies have shown no relationship between IAs and diabetic angiopathic complications, including nephropathy, retinopathy, and neuropathy. With the advent of novel insulin formulations and delivery systems, such as insulin pumps and inhaled insulin, examination of these issues is increasingly relevant.

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“…At present we have insuffi-144 cient data on "big insulin" with which to compare it with "proinsulin." Likewise we are as yet unable to relate our work to studies by others on the heterogeneity of pancreatic insulin.23 24 The biological activity of "big insulin," its chemical nature, and its physiological significance are unclear. However, our findings indicate that the physiology of insulin secretion must be re-examined completely, especially in those conditions in man characterized by glucose intolerance with hyperinsulinism such as starvation, obesity, and maturity onset diabetes mellitus.…”

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confidence: 93%

"Big insulin": a new component of plasma insulin detected by immunoassay.

Roth¹,

Görden²,

Pastan³

1968

Proc. Natl. Acad. Sci. U.S.A.

142

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Since the advent of radioimmunoassay, I the concentration of insulin in plasma of normal and diabetic subjects in response to many stimuli has been studied extensively.2 However, the chemical nature of the circulating hormone is not entirely clear. We find that endogenous plasma insulin has two components.One is very similar to pancreatic insulin. The other component is larger in size and immunologically less reactive than pancreatic insulin. With our antiserum, it accounts for up to 50 per cent of plasma insulin measured by immunoassay.Materials and Methods.-Purified crystalline porcine and bovine insulin were gifts of Eli Lilly. Highly purified A-chain and B-chain sulfonates of bovine insulin were gifts of Dr. Arnold Marglin.' Cytochrome c, pancreatic ribonuclease, and porcine adrenocorticotropin (ACTH) were purchased from Mann, crystalline human serum albumin from Armour, rabbit fraction II and normal guinea pig serum from Pentex, guinea pig fraction II from Hyland, and NaI'25 and NaI"11 from Union Carbide. Guinea pig antiporcine insulin serum was a gift of Drs. A. Kagan and S. M. Glick. Antibody to guinea pig gamma globulin was generated in sheep by repeated injection of guinea pig fraction II in complete Freund's adjuvant (Difco). Albumin and ACTH were labeled with 112 and insulin with I'll by the chloramine T method at specific activities of 5, 5, and 450 uc/igg, respectively.4 The albumin-I125 was freed of radioactive contaminants by batch adsorption with Dowex 1X10. The ACTH-I'25 was purified by adsorption to silica and elution with acetic acid and acetone.' The insulin-I131, prepared fresh for each assay, was purified on a cellulose column.1 The normal subjects for the experiments were healthy male volunteers in their early twenties without a family history of diabetes. For the standard oral glucose tolerance tests 100 gm of glucose was administered in the morning after an overnight fast; for 3 days prior to the studies the subjects received a normal diet that included 300 gm of carbohydrate daily. For the starvation tests, food was withheld until the urine reacted strongly positive for acetone; the fast, about 36 hr in duration, was terminated by the administration of glucose, 100 gm orally. Patient MIT is an obese adult female with long-standing glucose intolerance, delayed hyperinsulinism following oral glucose, and retinal microaneurysms typical of diabetes. Plasma that was essentially free of insulin was obtained after a 72-hr fast from a patient who had had an islet-cell adenoma removed several years earlier. None of the subjects had ever been treated with insulin.Blood was drawn into heparin, refrigerated, and centrifuged, and the plasma stored at -20°. Plasma, 1-3 ml, was enriched with albumin-I125 and iodidel25 and applied to a 1 X 50-cm column of Sephadex G-50 fine (Pharmacia). Shorter columns or coarser grades of gel were unsatisfactory. Since the results of radioimmunoassay can be affected by variations in the salt content of the samples,' the column was equilibrated and developed in the same...

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Heterogeneity of Crystalline Insulin1

Cited by 49 publications

References 0 publications

Chicken Insulin: Radioimmunological Characterization and Enhanced Activity in Rat Fat Cells and Liver Plasma Membranes

Chicken Insulin: Radioimmunological Characterization and Enhanced Activity in Rat Fat Cells and Liver Plasma Membranes

Immunological Responses to Exogenous Insulin

"Big insulin": a new component of plasma insulin detected by immunoassay.

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