Sexual hormone in the cellular slime mould Dictyostelium purpureum.

The existence of sexual hormone in Dictyostelium purpureum was revealed when the extracelluar medium from certain strains (Dp6 or Dp7) induced macrocyst formation when added to cells of the opposite mating type (Dp2). Our results suggest that mating in cellular slime moulds may involve a secreter-responder system whereby one mating-type strain (Dp6 or Dp7) releases sexual hormone while the opposite strain (Dp2) responds. However, the existence of a hormone released by the responding strain has not been completely ruled out by our experiments. The sexual hormones of cellular slime moulds appear to be species-specific since hormone from D. purpureum cannot induce macrocyst formation in responder strains of D. discoideum and hormone from D. discoideum has no effect on D. purpureum cells.