Impact of complete isletectomy on plasma glucose in the southern hemisphere lamprey Geotria australis

Epple, August; Cake, Max H.; Potter, I. C.; Tajbakhsh, M.

doi:10.1016/0016-6480(92)90112-w

Cited by 10 publications

(6 citation statements)

References 15 publications

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“…Interestingly, it appears that many of the somatostatin cells from the gut have now migrated into the islet organ (Yui et al 1988). One very interesting difference between the lamprey and hagfish is that removal of the islet organ in lamprey but not hagfish induced hyperglycemia (Epple and Brinn 1986;Epple et al 1992). …”

Section: Agnatha-cyclostomes: First Appearance Of An Islet Organmentioning

confidence: 97%

“…Insulin (red), glucagon (green), somatostatin (blue), pancreatic polypeptide (yellow), ghrelin (purple). BD, bile duct (Epple and Brinn 1986). The lamprey, a bottom-dwelling ocean fish relative of the hagfish, also has a distinct islet organ, which was described by August Epple as follicles of Langerhans due to its curious structure and that it was embedded in the submucosa of the intestine and features a duct-like lumen (Epple and Brinn 1986).…”

Section: Agnatha-cyclostomes: First Appearance Of An Islet Organmentioning

confidence: 99%

“…Thus, it appears that insulin is the first hormone to have left the nervous system for the gut. Amphioxus is the earliest species for which all four of the main endocrine cell types are found in the GI tract, but not yet organized into an islet organ (Epple and Brinn 1986) (Fig. 2).…”

Section: Invertebratesmentioning

confidence: 99%

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The Comparative Anatomy of Islets

Heller¹

2014

Islets of Langerhans

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Section: Agnatha-cyclostomes: First Appearance Of An Islet Organmentioning

confidence: 97%

Section: Agnatha-cyclostomes: First Appearance Of An Islet Organmentioning

confidence: 99%

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The Comparative Anatomy of Islets

Heller¹

2014

Islets of Langerhans

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“…The physiological role of the gastroenteropancreatic hormones in the regulation of metabolism in Agnatha is unclear. Studies with G. australis are of particular importance in this regard as the species allows complete removal of the islet tissue without major damage to other tissues (Epple et al, 1992). Total isletectomy resulted in an immediate rise in plasma glucose concentrations (from 5.0 to 11.6 mM) that remained elevated for at least 5 days indicating a possible glycogenolytic and/or gluconeogenic action of intestinally derived glucagon in the absence of insulin.…”

Section: Discussionmentioning

confidence: 99%

Multiple Forms of Glucagon and Somatostatin Isolated from the Intestine of the Southern-Hemisphere LampreyGeotria australis

Wang

Nielsen

Youson

et al. 1999

General and Comparative Endocrinology

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Current views on Agnathan phylogeny favor the hypothesis that the genera of holarctic lampreys belong to a single family (Petromyzontidae) and form an interrelated progression in which Petromyzon is near to Ichthomyzon at the base of the phylogenetic tree and Lampetra is the most derived. A stock similar to that of contemporary Ichthomyzon is considered to have given rise to the southern hemisphere lamprey Geotria australis, the sole member of the Geotriidae. In the present study, two molecular forms of glucagon were isolated from an extract of G. australis intestine that differed in structure by six amino acid residues. One form shows two amino acid substitutions (Leu14 --> Met and Ala29 --> Ser) compared with the single molecular form of glucagon isolated from the sea lamprey Petromyzon marinus and the second form shows three substitutions (Asp15 --> Glu, Ser16 --> Ala, Ile24 --> Thr) compared with the single glucagon isolated from the river lamprey Lampetra fluviatilis. As Petromyzon and Lampetra glucagons differ by six amino acid residues, the data suggest that a duplication of the glucagon gene occurred prior to or early in lamprey evolution. Although both genes are strongly expressed in G. australis, the expression of one gene predominates in P. marinus while that of the other gene predominates in L. fluviatilis. Previous work has shown that, in the islet organ of G. australis, preprosomatostatin is processed almost exclusively to somatostatin-33. However, the present study demonstrates that somatostatin-14 is the major molecular form in G. australis intestine with somatostatin-33 present only as a minor component. This result demonstrates a tissue-dependent pathway of posttranslational processing of preprosomatostatin in the Geotria enteropancreatic system.

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“…16 days (Kelley, 1993). Similarly, complete isletectomy performed on Southern lamprey Geotria australis by Epple, A and coworkers (Epple et al, 1992) resulted in a marked increase in blood glucose level. In general, the hypoglycemic action of insulin in ectotherms develop more slowly and can require days instead of hours to achieve a full effect.…”

Section: Structure and Function Of Insulin Andmentioning

confidence: 92%

Insulin Through the Ages: Phylogeny of a Growth Promoting and Metabolic Regulatory Hormone1

Chan

Steiner

2000

American Zoologist

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SYNOPSIS. Insulin was discovered in 1922 as the causative factor for a human metabolic disorder (diabetes mellitus), but it was recognized early that the hormone had a broad phylogenetic distribution. By the mid 1970s, insulin had been isolated and sequenced from all classes of vertebrates, including Agnatha. Also it was discovered that the insulin gene family in vertebrates included two closely related hormones named insulin-like growth factor (IGF)-I and-II. More recently, the application of recombinant DNA techniques have identified insulin-like peptide genes in invertebrates, including insects, molluscs and nematode and these findings clearly establish that insulin is an evolutionarily ancient hormone which is present in all metazoa. Here we briefly review the structure and function of the insulin/ IGF gene family in vertebrates and invertebrates. Although these studies are ongoing, it appears that in invertebrates the insulin-like peptides function predominately as mitogenic growth factors that act to promote tissue growth and development. However, in vertebrates the mitogenic growth function has been subsumed by IGF-I and-II while insulin has acquired the function of being primarily a metabolic regulatory hormone. The gene duplication and divergence events necessary for this development probably occurred early during vertebrate evolution in the transition from protochordates, represented by extant amphioxus, to primitive jawless vertebrates, represented by extant lamprey and hagfish.

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Impact of complete isletectomy on plasma glucose in the southern hemisphere lamprey Geotria australis

Cited by 10 publications

References 15 publications

The Comparative Anatomy of Islets

The Comparative Anatomy of Islets

Multiple Forms of Glucagon and Somatostatin Isolated from the Intestine of the Southern-Hemisphere LampreyGeotria australis

Insulin Through the Ages: Phylogeny of a Growth Promoting and Metabolic Regulatory Hormone1

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