Purification and partial characterization of mosquito egg development neurosecretory hormone: Evidence for gonadotropic and steroidogenic effects

Publisher Website
Google Scholar
Abstract
Egg development neurosecretory hormone (EDNH), a hormone that stimulates vitellogenesis in mosquitoes, was purified 10,000‐fold from the mosquito Aedes aegypti. The purification procedure included chromatography on hydrophobic, ion exchange, and gel filtration columns, and preparative electrophoresis to give an almost homogeneous preparation. The hormone is a polypeptide monomer of molecular weight of 18,700 ± 500 as determined from SDS electrophoresis and gel filtration chromatography. Using lowpressure chromatography throughout the purification procedure, the hormone was recovered at a high yield (39%). The amount of EDNH in a mosquito is about 0.6‐1.6 ng, corresponding to 32–85 fmol.Injection of purified EDNH into female mosquitoes resulted in the conversion of [14C]cholesterol into labeled ecdysone and 20‐hydroxyecdysone which were separated and identified using thin‐layer chromatography and high‐performance liquid chromatography separation procedures.Egg development and vitellogenin synthesis were also induced when EDNH was injected into several mosquito species, indicating that the hormone is not species‐specific.This report is the first to show that a purified preparation of EDNH has both steroidogenic and a gonadotropic effects on female mosquitoes.