Humoral factors influencing erythropoiesis in the fish (blue gourami. Trichogaster trichopterus).

STRONG EVIDENCE has accumulated to indicate that erythropoiesis in mammals is under the control of a circulating principle, the erythropoiesisstimulating factor ( ESF ) or erythropoietin.1’2 A similar regulatory system may be operative in amphibians and birds.3’4 The ESF appears in large quantities in the plasma of animals subjected to bleeding or low oxygen pressures’ and its production is inhibited in starved and plethoric animals.5 Among the mammals a lack of species specificity for the ESF is evident. Thus ESF of human origin stimulates red blood cell ( RBC ) production in mice, rats and humans.1’6 On the other hand, class specificity for this principle appears to exist since mammalian ESF fails to stimulate erythropoiesis in the frog and bird, while plasma from bled frogs and birds is ineffective in mice.3’4 In an attempt to derive additional information on the phylogeny of the ESF, the present studies were performed in the teleost fish commonly termed the blue gourami ( Trichogaster trichopterus).