|Methionine-enkephalin induces hyperglycemia through eyestalk hormones in the estuarine crab Scylla serrata|
Reddy, P.S.; Kishori, B. (2001). Methionine-enkephalin induces hyperglycemia through eyestalk hormones in the estuarine crab Scylla serrata. Biol. Bull. 201: 17-25
In: Biological Bulletin. Marine Biological Laboratory: Lancaster, Pa. etc.. ISSN 0006-3185, more
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The hypothesis is tested that methionine-enkephalin, a hormone produced in and released from eyestalk of crustaceans, produces hyperglycemia indirectly by stimulating the release of hyperglycemic hormone from the eyestalks. Injection of methionine-enkephalin leads to hyperglycemia and hyperglucosemia in the estuarine crab Scylla serrata in a dose-dependent manner. Decreases in total carbohydrate (TCHO) and glycogen levels of hepato-pancreas and muscle with an increase in phosphorylase activity were also observed in intact crabs after methionine-enkephalin injection. Eyestalk ablation depressed hemolymph glucose (19%) and TCHO levels (22%), with an elevation of levels of TCHO and glycogen of hepatopan-creas and muscle. Tissue phosphorylase activity decreased significantly during bilateral eyestalk ablation. Administration of methionine-enkephalin into eyestalkless crabs caused no significant alterations in these parameters when compared to eyestalk ablated crabs. These results support the hypothesis that methionine-enkephalin produces hyperglycemia in crustaceans by triggering release of hyperglycemic hormone from the eyestalks.