Cadmium and mercury-induced hyperglycemia in the fresh water crab, Oziotelphusa senex senex: Involvement of neuroendocrine system

• Published in: Ecotoxicology and environmental safety 2011-03, Vol.74 (3), p.279-283
• Main Authors: Sreenivasula Reddy, P., Ramachandra Reddy, P., Sainath, S.B.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Brachyura - drug effects; Brachyura - metabolism; Cadmium; Cadmium - metabolism; Cadmium - toxicity; Cadmium and mercury; Control equipment; Crab; Crabs; Crustacea; Decapoda; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Exposure; Eyestalk ablation; Fresh water; Fresh Water - chemistry; freshwater; Fundamental and applied biological sciences. Psychology; General aspects; Glucose; Glucose - metabolism; glycemic effect; Hemolymph - metabolism; Hemolymph glucose; hormone secretion; Hormones; Hyperglycemia; Hyperglycemia - chemically induced; Hyperglycemia - metabolism; Hyperglycemic hormone; Invertebrates; Male; mercuric chloride; mercury; Mercury - metabolism; Mercury - toxicity; neurosecretory system; Neurosecretory Systems - drug effects; Oziotelphusa senex senex; Secretions; sublethal effects; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2010.10.031

The effect of exposure to sublethal concentrations of cadmium chloride and mercuric chloride on hemolymph glucose levels of the freshwater crab, Oziotelphusa senex senex, was studied. Intact crabs exposed to cadmium or mercury exhibited a significant hyperglycemia compared to controls, but no significant differences in hemolymph glucose level were detected among the eyestalkless crabs after exposure to metals, suggesting that the effect of metals could be on the sinus gland in the eyestalks, increasing secretion of the hyperglycemic hormone. To test this hypothesis, eyestalks were collected from control and metal exposed crabs, and tested for hyperglycemic effect and also for the hyperglycemic hormone levels. The levels of hyperglycemic hormone and the hyperglycemic effect were significantly low in the eyestalks collected from metal exposed crabs when compared with eyestalks from control crabs. These results strongly suggest that metals act, at least in part, by triggering the secretion of hyperglycemic hormone from the eyestalk.