Persistent vitellogenin-like protein and binding of DDT in the serum of insecticide-resistant mosquitofish (Gambusia Affinis)

1. During the reproductive season the serum of most oviparous teleosts contains an electrophoretically-identifiable protein, vitellogenin. 2. However, serum from insecticide-resistant mosquitofish contain a vitellogenin-like protein (VLP) year round. 3. It is suggested that estrogenic and/or proestrogenic xenobiotics from the environment of the fish induces the formation of this protein during the non-reproductive season. 4. In vitro incubation of [p,p′-³H]DDT with reproductive or non-reproductive resistant and susceptible fish serum, led to its association with three separate proteins (VLP, a low molecular weight lipoprotein and albumin). 5. Xenobiotics thus may induce the formation of protein (VLP), in non-reproductive resistant fish, which can bind and transport insecticides.