Detection of CHH/GIH activity in fractionated extracts from the eyestalk of Banana prawn

Sinus gland from Penaeus merguiensis De man, 1888 was extracted and proteins were fractionated on a HPLC column (μBondapack-phenyl column, 9 mm i.d., 10 μm particle size, Waters). Three major peaks (peaks 3, 5 and 6) were collected and investigated for crustacean hyperglycemic hormone (CHH) and gonad inhibiting hormone activity (GIH). The CHH activity of the peak 5 fraction was significantly higher than the control while peak 6 did not have significant CHH activity. No CHH activity was found in the peak 3 fraction. GIH activity was determined by inhibition of total protein and vitellin synthesis in ovarian tissue. An antivitellin antibody was prepared and used for immunoprecipitation in the GIH activity assay. Hence GIH activity was detected in peaks 5 and 6 while peak 3 had gonad stimulating hormone like activity (GSH-like activity).