Effects of crustacean hyperglycemic hormone (CHH) on carbohydrate metabolism-related enzymes in the kuruma prawn, Marsupenaeus japonicus
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1
The University of Tokyo, Department of Applied Biological Chemistry, Japan
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2
The University of Wyoming, Department of Molecular Biology, United States
In crustaceans, eyestalk ablation causes various physiological events, including decrease of the hemolymph glucose level by lacking of a neuropeptide, crustacean hyperglycemic hormone (CHH). Although the hyperglycemic activity of CHH is well documented, little has been investigated on its functional regulation at a molecular level. In this study, to clarify the mechanism of the regulation, we analyzed the effects of CHH on glycogen metabolism and gluconeogenesis.
We first cloned cDNAs encoding four carbohydrate metabolism-related enzymes; glycogen phosphorylase (MjGP), glycogen synthase (MjGS), fructose 1,6-bisphosphatase (MjFBPase), and phosphoenolpyruvate carboxykinase (MjPEPCK) from Marsupenaeus japonicus by degenerate PCR, and then analyzed their expression levels by RT-PCR. The results showed that eyestalk ablation two days before the experiment decreased the mRNA level of MjGP, while this treatment increased that of MjGS in a main tissue for glycogen storage, hepatopancreas as well as in other tissues, indicating that the eyestalk-ablated prawns declined to the metabolic condition for glycogen accumulation. On the other hand, little changes in the levels of MjFBPase and MjPEPCK were observed, indicating that hypoglycemic condition caused by eyestalk ablation might not be due to hormonal regulation via gluconeogenesis. We next analyzed the mRNA levels of the four enzymes in the hepatopancreas and muscle by ex vivo stimulation of CHH. Quantative RT-PCR analyses showed that the mRNA levels of these enzymes in the examined tissues did not change after 1 hour exposure to 100 nM CHH, indicating that carbohydrate metabolism may not be transcriptionally regulated by CHH at least in a short period.
Keywords:
comparative endocrinology
Conference:
25th Conference of the European Comparative Endocrinologists, Pécs, Hungary, 31 Aug - 4 Sep, 2010.
Presentation Type:
Conference Presentation
Topic:
Comparative endocrinology
Citation:
Nagai
C,
Mabashi-Asazuma
H,
Shinji
J and
Nagasawa
H
(2010). Effects of crustacean hyperglycemic hormone (CHH) on carbohydrate metabolism-related enzymes in the kuruma prawn, Marsupenaeus japonicus.
Front. Endocrinol.
Conference Abstract:
25th Conference of the European Comparative Endocrinologists.
doi: 10.3389/conf.fendo.2010.01.00048
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Received:
26 Aug 2010;
Published Online:
29 Aug 2010.
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Correspondence:
Ms. Chiaki Nagai, The University of Tokyo, Department of Applied Biological Chemistry, Tokyo, Japan, chi-a-ki@dg8.so-net.ne.jp