title: Portal serum constituents possible determinants for anatomical localization ofSchistosoma mansoni during maturation and reproduction.
abstract: Coupled adult pairs ofSchistosoma mansoni were incubated in medium containing either peripheral or portal serum from rat, rabbit, hamster, or man, and egg production was measured daily. In all cases egg production was significantly increased for pairs in the presence of portal sera compared with that in the presence of peripheral sera. Fractionation of rabbit portal serum according to molecular weight demonstrated that the most active component(s) were in the range of 2000 to 50,000. Similarly, a rat portal serum fraction in the range of 2000 to 30,000 molecular weight was most stimulatory. These fractions were as effective in stimulating oviposition as whole portal serum.
  
  
  CONCLUSIONS
  (1) portal serum factor(s) exist that stimulateS. mansoni oviposition in vitro; (2) they are present in susceptible and nonsusceptible hosts; and (3) the molecular weight range for the active components is larger than would be expected for simple carbohydrates, amino acids, or free fatty acids absorbed from the gastrointestinal tract.
authors.affiliation: Department of Medicine Division of Gastroenterology, University of Connecticut School of Medicine, 06032, Farmington, Connecticut.
authors.forename: G Y
authors.initials: GY
authors.lastname: Wu
authors.forename: C H
authors.initials: CH
authors.lastname: Wu