Disruption of endocrine regulation of glycemia levels by cadmium and copper, in the estuarine crab Chasmagnathus granulata

MEDESANI, D.A.; LÓPEZ GRECO, L.S.; RODRÍGUEZ, E.M.; IANOWSKY, J.P.

Congreso; 2003 Annual Meeting, Society for Integrative and Comparative Biology; 2003

Carbohydrate metabolism has been one of the topics extensively studied in crustaceans. The so-called “crustacean hyperglycemic hormone” (CHH) is a peptide of about 70 amino acids, which has been isolated and sequenced for several crustacean species. It belongs to a family of neuropeptides, all of them released from the sinus gland in the eyestalks. In this study, the effects of cadmium and copper on the glycemia level in the estuarine crab Chasmagnathus granulata was evaluated after a 2-wk exposure to low levels of each of these heavy metals (0.5 and 0.1 mg/L for cadmium and copper, respectively). In both cases, a significant hypoglycemia developed. When crabs were subsequently injected with exogenous CHH (32 pmoles/crab, purified from Cancer pagurus, the hypoglycemia was reversed. In the cadmium-exposed crabs, a similar glucose level to that of the control crabs also injected with CHH was attained, demonstrating that this heavy metal is not interfering with hormonal reception and/or transduction in the target tissues. In the case of the copper-exposed crabs, the increase of glycemia after CHH injection was less han in the control crabs, suggesting that some interference with hormonal transduction or with the enzymes involved in glucose mobilization could have occurred to some extent.