Effects of leucine-enkephalin on alpha-naphthyl acetate esterase and myeloperoxidase activity in haemolymph of the scallop Chlamys farreri

The study was designed to investigate the effects of leucineenkephalin (L-ENK) on the activity of alpha-naphthyl acetateesterase (ANAE) and myeloperoxidase (MPO) in haemolymph ofthe scallop Chlamys farreri. Our results indicate that MPO activitywith DAB and DEA substrate solution was induced when theconcentration of L-ENK was 5 and 50 μg/ml, and the intracellularand extracellular MPO activity with two substrate solutions washighest when the concentration of L-ENK was 50 μg/ml. However,both the intracellular and extracellular MPO activity of 1 μg/mlgroup was significantly lower than that of control group. It was alsofound that the intracellular and extracellular ANAE activity wasinduced by L-ENK. The supernatant ANAE activity was highestwhen the concentration of L-ENK was 50 μg/ml, but the resultantHLS ANAE activity was highest when the concentration of L-ENKwas 5 μg/ml. Overall, the data suggests an involvement of L-ENK inthe regulation of the defense systems of the scallop Chlamys farreri.L-ENK may function as messengers in the bidirectional interactionbetween the neuroendocrine and the immune systems.