The nature of human serum insulin-like activity (ILA): characterization of ILA in serum and serum fractions obtained by acid-ethanol extraction and adsorption chromatography

Poffenbarger, Phillip L.; Ensinck, John W.; Hepp, Dieter; Williams, Robert H.

doi:10.1172/jci105726

Cited by 26 publications

(13 citation statements)

References 62 publications

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“…Gel-filtration of fraction S (soluble in acidethanol) on Sephadex G-100 at neutral pH yielded an elution pattern of nonsuppressible ILA similar to that found by other authors working with Sephadex at neutral pH ( 18,20). Thus, Cameron, Boyns, Jarrett, and Keen (17) found that ILA of a trichloroacetic acid extract of human plasma eluted from Sephadex G-200 at neutral pH over a wide range.…”

Section: Discussionsupporting

confidence: 69%

“…(18) that "bound insulin" and nonsuppressible ILA soluble in acid-ethanol (fraction S) are the same. The controversal estimates of the molecular size clearly are due to the different conditions chosen for Sephadex chromatography.…”

Section: Discussionmentioning

confidence: 95%

“…Recently, Poffenbarger et al (18) suggested that "bound insulin," "atypical insulin," and nonsuppressible ILA are all one and the same substance. Two types of experiments were designed to test this hypothesis.…”

Section: Discussionmentioning

confidence: 99%

“…Proteins retained on the column eluted with 0.02 N NH4OH into 0.2 N H2S04 under constant stirring (alkaline eluate). The NaCl wash and alkaline eluate were prepared for the bioassay by lyophilization and dialysis as outlined by Poffenbarger, Ensinck, Hepp, and Williams (18).…”

Section: Methodsmentioning

confidence: 99%

“…The mol wt of nonsuppressible ILA of native serum was estimated in two different laboratories by gel-filtration to be' approximately 150,000 (10,16). After extraction and purification nonsuppressible ILA was reported by several different groups of investigators to have a mol wt greater than 100,000 (17), 50,000-70,000 (18,19), and 6000 (10), respectively.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Nonsuppressible insulin-like activity in human serum

Jakob¹,

Hauri²,

Froesch³

1968

J. Clin. Invest.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Nonsuppressible insulin-like activity in human serum

Jakob¹,

Hauri²,

Froesch³

1968

J. Clin. Invest.

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Circulating Insulins

Görden¹

1969

Arch Intern Med

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Plasma insulin has been characterized by its biologic, immunologic, physical, and chemical similarity to pancreatic insulin. A higher molecular weight heterogenous component (peak "b") of pancreatic insulin that contains the biosynthetic precursor of insulin (proinsulin) has recently been described. Plasma insulin as measured by radioimmunoassay is composed of at least two components. Filtration of plasma on G-50 Sephadex yields a major component ("little" insulin) which is indistinguishable from the major component of pancreatic insulin and a second component "big" insulin which is less retarded by the gel similar to peak "b." Both components react strongly with insulin antisera and are secreted by the pancreas in response to stimuli of insulin secretion. The characteristics of these recently described components of pancreatic and of plasma insulin are described and discussed.Despite widespread use of radioimmunoassay for the measure¬ ment of polypeptide hormones in plasma and great advances in meth¬ ods for the fractionation of proteins, very few studies have appeared on the nature of circulating hormones.In trying to characterize plasma hor¬ mones several impediments are en¬ countered. First the concentrations of the polypeptide hormones in plas¬ ma rarely exceed 10_8 M, whereas plasma proteins are present at about 100,000 times greater concentration.In comparison with purification of hormones from glands, not only is it much more difficult to obtain from plasma sufficient material on which to perform studies but the number of individual substances from which the hormone must be separated during purification is much greater. Another impediment is that the biological as¬ says that were developed for the study of hormones that were ex¬ tracted from glands usually lack sufficient sensitivity, specificity, pre¬ cision, or ease of assay to be of use in studying plasma hormone.In our present discussion on the nature of circulating insulin, we have restricted ourselves to those sub¬ stances in plasma that react with antibodies to insulin. The large num¬ ber of substances in plasma that possess biological properties of insu¬ lin but whose biological effects are unaltered by the addition of insulin antibody have been reviewed else¬ where i"3 and will not be discussed.Although our discussion, in effect will be restricted to insulin in plasma detected by immunoassay, it should be noted that findings by immuno¬ assay are closely paralleled by mea¬ surements of suppressible insulin¬ like activity,1 which is the portion of insulin-like biological activity of

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Die biologische Bestimmung der insulinähnlichen Serumaktivität (ILA)

Ditschuneit¹,

Faulhaber²

1971

Pathophysiologie Und Klinik / Pathophysiology and Clinical Considerations

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The nature of human serum insulin-like activity (ILA): characterization of ILA in serum and serum fractions obtained by acid-ethanol extraction and adsorption chromatography

Cited by 26 publications

References 62 publications

Nonsuppressible insulin-like activity in human serum

Nonsuppressible insulin-like activity in human serum

Circulating Insulins

Die biologische Bestimmung der insulinähnlichen Serumaktivität (ILA)

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