Gonadotrophic hormone inEulalia viridis(Polychaeta, Annelida): Stimulation of vitellogenesis

Summary Incorporation of 3H-leucine into TCA extracted, water soluble oocyte proteins is significantly enhanced in in vivo cultures of Eulalia viridis which have intact supra-oesophageal ganglia and those which have undergone replacement therapy when compared to decerebrate treatments. This response is gonad specific, with no differences in the rate of uptake of 3H-leucine into gut proteins between treatments. There was no significant difference in the rate of protein synthesis between oocytes cultured in vitro in the presence or absence of supra-oesophageal ganglion homogenate on culture medium containing 3H-leucine. However, oocytes cultured in the presence of supra-oesophageal ganglion homogenate do show a significant increase in the rate of uptake of radiolabel when compared to oocytes cultured in the absence of prostomial homogenate when cultured on medium containing 3H-labelled oocyte protein. These results indicate the presence of a gonadotrophic hormone in the supra-oesophageal ganglion of Eulalia viridis which promotes the uptake of external egg protein into developing oocytes. It is suggested that this is, at least in part, a heterosynthetic process with 3H-leucine being incorporated into an external protein before incorporation into the developing oocytes.