Changes in crustacean hyperglycemic hormones in Pacific whiteleg shrimp Litopenaeus vannamei subjected to air-exposure and low-salinity stresses

Changes in crustacean hyperglycemic hormone (CHH)-family peptides in response to stress were investigated in Litopenaeus vannamei. Stress treatments consisted of air exposure and low salinity. High-performance liquid chromatography was used to quantify CHH-family peptides in the X-organ-sinus gland complex (XO-SG) in the eyestalks. Among the CHH-family peptides analyzed, only the level of sinus gland peptide-G (SGP-G) in the XO-SG was decreased. SGP-G was also detectable by Western blotting analysis in the hemolymph of animals subjected to stress. These results suggest that SGP-G was secreted from the XO-SG into the hemolymph during stress. Glucose levels in the hemolymph increased under conditions during which SGP-G was detected in the hemolymph. Hyperglycemia was also observed when SGP-G was injected. SGP-G may function to shift energy use to deal with stress.