Effects of crustacean hyperglycemic hormones from Carcinus maenas and Orconectes limosus on blood and muscle glucose and glycogen concentration of Chasmagnathus granulata.

The effects of purified crustacean hyperglycemic hormones (CHH) from Carcinus maenas or Orconectes limosus, and of eyestalk extract of Chasmagnathus granulata on the blood and muscle glucose and glycogen concentration of Chasmagnathus granulata were investigated. Different groups of animals (at least 7 animals per group) were injected with CHH from either C. maenas or O. limosus CHH dissolved in saline (16 pmol/animal) or crude eyestalk extract of C. granulata (1 eyestalk equivalent/animal). All injections had a volume of 10 microliters. Blood and muscle glucose and glycogen concentrations were determined immediately before the injections and after 30, 60 and 120 min. CHH administration from both species, as well as eyestalk extract, resulted in marked hyperglycemia. However, their effects were different. CHH from C. maenas also caused a decrease in the glycogen concentration of blood (from 89.8 +/- 4.3 to 76.6 +/- 3.1 mg/100 ml) and muscle (from 7.9 +/- 0.8 to 4.0 +/- 0.7 mg/g) and glucose concentration of muscle (from 2.4 +/- 0.3 to 1.2 +/- 0.2 mg/g). CHH from O. limosus caused an increase of glycogen concentration of muscle (from 4.9 +/- 1.1 to 9.0 +/- 1.1 mg/g). The injection of eyestalk extract resulted also in a decrease of hemolymph glycogen (from 157.7 +/- 20.6 to 30.2 +/- 7.7 mg/100 ml). Therefore, C. granulata may have different receptors for CHH in its different tissues, and/or in the same tissue, which act through different metabolic pathways to achieve the same final result, i.e., hyperglycemia.