Reversed-phase high-performance liquid chromatographic analyses of insulin biosynthesis in isolated rat and mouse islets

Linde, Susanne; Nielsen, Jens Høiriis; Hansen, Bruno; Welinder, Benny S.

doi:10.1016/s0021-9673(00)91351-7

Cited by 30 publications

(18 citation statements)

References 20 publications

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“…This material has been identified as mouse insulin II oxidized at methionine B29 (29), and for the purposes of calculating the relative amounts of the various insulin species is considered as mouse insulin II. As expected for the pancreas of a mouse ( 15,19), there was more than twice as much insulin II than I.…”

Section: Biochemistrysupporting

confidence: 77%

Adaptation to supraphysiologic levels of insulin gene expression in transgenic mice: evidence for the importance of posttranscriptional regulation.

Schnetzler

Murakawa²,

Abalos³

et al. 1993

J. Clin. Invest.

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Insulin production was studied in transgenic mice expressing the human insulin gene under the control of its own promoter. Glucose homeostasis during a 48-h fast was similar in control and transgenic mice, with comparable levels of serum immunoreactive insulin. Northern blot and primer extension analyses indicated that more than twice as much insulin mRNA is present in pancreata from transgenic mice. Primer extension analysis using oligonucleotides specific for mouse insulins I and II or for human insulin, showed that the excess insulin mRNA was due solely to expression of the foreign, human insulin gene. The ratio of mRNA for mouse insulin I and II was unaffected by coexpression of human insulin. There were coordinate changes in the levels of all three mRNA during the 48-h fast, or after a 24-h fast followed by 24-h refeed. Despite the supraphysiologic levels of insulin mRNA in the transgenic mice, their pancreatic content of immunoreactive insulin was not significantly different from controls. The comparison of the relative levels of human and mouse insulin mRNAs with their peptide counterparts (separated by HPLC) indicates that the efficiency of insulin production from mouse insulin mRNA is greater than that from human, stressing the importance of posttranscriptional regulatory events in the overall maintenance of pancreatic insulin content. (J. Clin. Invest. 1993. 92:272-280.)

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Section: Biochemistrysupporting

confidence: 77%

Adaptation to supraphysiologic levels of insulin gene expression in transgenic mice: evidence for the importance of posttranscriptional regulation.

Schnetzler

Murakawa²,

Abalos³

et al. 1993

J. Clin. Invest.

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“…Despite the ease of separation of rat C-peptides I and II, and rat insulins I and II by HPLC [3][4][5][6], the separation of the two rat proinsulins has not proved as simple [3,6]. Based upon the dramatic change in mobility of rat insulin II following oxidation of Met B29, we speculated that [Met-OB29]proinsulin II may prove readily separable from both native proinsulin II and, more importantly, from rat proinsulin I.…”

Section: Resultsmentioning

confidence: 99%

“…This analytical method has allowed for separation of the protein products of the two non-allelic rat insulin genes, rat insulins I and II [3][4][5][6] and rat C-peptides I and II [7]. The separation of rat proinsulin I and II by HPLC proved not to be as successful [3,6].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of rat insulin II, but not I, leads to anomalous elution profiles upon HPLC analysis of insulin‐related peptides

et al. 1988

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Rat insulin II, unlike rat insulin I and other non-rodent insulins, contains a unique methionine residue at position B29. Reversed-phase HPLC allows for separation of the two rat insulins, with insulin I typically eluting faster than insulin II. An anomalous peak of insulin immunoreactive material was found eluting even faster than insulin I following acid extraction of rat insulin-producing cells. This early peak co-eluted with insulin II suggesting that during cell extraction and subsequent purification steps, rat insulin II is subject to selective oxidation at Met s29. Such oxidation of rat proinsulin II affords improved separation from rat proinsulin I compared to the native form.

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“…Fully processed INS1 and INS2 peptides differ at the level of two B-chain amino acids, with additional differences evident in their C-peptides (Wentworth et al 1986). Despite sharing sequence homology upstream of the transcription initiation site (Wentworth et al 1986, Melloul et al 2002, Ins1 and Ins2 do have notable differences with respect to certain promoter elements, expression patterns, translational efficiency and imprinting status (Wentworth et al 1986, Linde et al 1989, Deltour et al 1995, Hay & Docherty 2006, Meur et al 2011, Mehran et al 2012. Ins2 can be detected earlier in murine development and has a broader tissue distribution (Deltour et al 1993, Fan et al 2009, Mehran et al 2012.…”

Section: Phylogeny and Complexity Of Insulin-like Peptides And The Inmentioning

confidence: 99%

“…Ins2 can be detected earlier in murine development and has a broader tissue distribution (Deltour et al 1993, Fan et al 2009, Mehran et al 2012. Murine Ins1 expression and promoter activity are largely restricted to the pancreas (Mehran et al 2012, Thorens et al 2015, and it does not contribute as much to pancreatic insulin production as Ins2, except in the mouse embryo during the early stages of pancreatic development (Wentworth et al 1986, Linde et al 1989, Deltour et al 1993, Bengtsson et al 2005. Complete inactivation of both Ins genes in mice (i.e.…”

Section: Phylogeny and Complexity Of Insulin-like Peptides And The Inmentioning

confidence: 99%

A causal role for hyperinsulinemia in obesity

Templeman

Skovsø

Page

et al. 2017

Journal of Endocrinology

134

116

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Insulin modulates the biochemical pathways controlling lipid uptake, lipolysis and lipogenesis at multiple levels. Elevated insulin levels are associated with obesity, and conversely, dietary and pharmacological manipulations that reduce insulin have occasionally been reported to cause weight loss. However, the causal role of insulin hypersecretion in the development of mammalian obesity remained controversial in the absence of direct loss-of-function experiments. Here, we discuss theoretical considerations around the causal role of excess insulin for obesity, as well as recent studies employing mice that are genetically incapable of the rapid and sustained hyperinsulinemia that normally accompanies a high-fat diet. We also discuss new evidence demonstrating that modest reductions in circulating insulin prevent weight gain, with sustained effects that can persist after insulin levels normalize. Importantly, evidence from long-term studies reveals that a modest reduction in circulating insulin is not associated with impaired glucose homeostasis, meaning that body weight and lipid homeostasis are actually more sensitive to small changes in circulating insulin than glucose homeostasis in these models. Collectively, the evidence from new studies on genetic loss-of-function models forces a re-evaluation of current paradigms related to obesity, insulin resistance and diabetes. The potential for translation of these findings to humans is briefly discussed.

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Reversed-phase high-performance liquid chromatographic analyses of insulin biosynthesis in isolated rat and mouse islets

Cited by 30 publications

References 20 publications

Adaptation to supraphysiologic levels of insulin gene expression in transgenic mice: evidence for the importance of posttranscriptional regulation.

Adaptation to supraphysiologic levels of insulin gene expression in transgenic mice: evidence for the importance of posttranscriptional regulation.

Oxidation of rat insulin II, but not I, leads to anomalous elution profiles upon HPLC analysis of insulin‐related peptides

A causal role for hyperinsulinemia in obesity

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