Lipopolysaccharide-Induced Hyperglycemia Is Mediated by CHH Release in Crustaceans

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• 作者：Lorenzon ; Simonetta ; Giulianini ; Piero Giulio ; Ferrero ; Enrico Antonio
• 刊名：General and Comparative Endocrinology
• 出版年：1997
• 出版时间：December, 1997
• 年：1997
• 卷：108
• 期：3
• 页码：395-405
• 全文大小：249 K

文摘

Septicemia in crustaceans may occur occasionally due to Gram-negative opportunistic bacteria, especially under conditions of intensive aquaculture. The lipopolysaccharide (LPS) endotoxin induces in mammals septic shock and the activation by LPS of hormone release through the hypothalamo–pituitary axis is well known. In crustaceans an increase in circulating Crustacean hyperglycemic hormone and hyperglycemia are reported to result from exposure to several environmental stressors but the metabolic and hormonal effects of LPSin vivoare undescribed. A sublethal dose of LPS (Sigma,Escherichia coli0111:B4) was injected into at least five individuals of species representative of crustacean taxa and life habits:Squilla mantis(Stomatopoda); the DecapodaCrangon crangonandPalaemon elegans(Caridea),Nephrops norvegicus(Astacidea),Munida rugosaandPaguristes oculatus(Anomura),Pilumnus hirtellus, Macropipus vernalis, Parthenope massena,andIlia nucleus(Brachyura). Within 3 hr an increase in blood sugar developed ranging from 26.00 ± 8.37 sd mg/dl inM. rugosato 201.50 ± 95.91 sd mg/dl inP. oculatusand a significant increase of 79 % inM. rugosaup to 1300 % inP. hirtellusover control levels was observed. The involvement of eyestalk hormones in this generalized response was tested onS. mantis, M. vernalis,andP. elegans;LPS injected into eyestalkless animals did not elicit a significant hyperglycemic response compared with saline-injected controls. Eyestalkless animals injected with one eyestalk equivalent homogenate in saline from untreated animals did show a change in color from red to normal likely due to red pigment concentrating hormone and a hyperglycemic response within 2 hr. Eyestalkless animals injected with homogenate from LPS-treated shrimps showed the change in color but not the hyperglycemic response. It is concluded that LPS directly, or cytokines circulated upon challenge by the endotoxin, may act on the medulla terminalis X-organ–sinus gland complex and release CHH selectively eliciting an hyperglycemic stress response, after which CHH stores become relatively depleted.