Determination of vitellogenin kinetics in male fathead minnows (Pimephales promelas).
A lack of knowledge persists concerning the combination of kinetics on protein and mRNA levels of the most commonly used biomarker for estrogenic influences-vitellogenin (VTG). Consequently, male fathead minnows were exposed to 17alpha-ethinylestradiol (EE(2)) for 35 days, followed by an equally long depuration period in a flow-through system. VTG mRNA levels reached a plateau after 3 days of exposure, which remained stable until 3 days after EE(2) removal. Control levels were re-attained within 7 days of the depuration phase. VTG protein accumulated in the plasma following a two-phased model. The first phase depicting an exponential increase lasted 15 days and was followed by a saturation phase approaching a plateau of approximately 47 mg VTG/ml plasma. Clearance kinetics could be described by a two-compartment open model, with half-lives of 2.17 and 21.32 days for the alpha- and beta-phases, respectively. In addition, a high VTG protein synthesis rate seemed to adversely affect fitness and mortality of the fish.
Schmid
T
T
Environmental Toxicology, University of Konstanz, Jacob-Burckhardstr. 25, 78457 Konstanz, Germany
Gonzalez-Valero
J
J
Rufli
H
H
Dietrich
D R
DR
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D003530:Cyprinidae / Q000502:physiology*; D045166:Estradiol Congeners / Q000633:toxicity; D004997:Ethinyl Estradiol / Q000633:toxicity; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006207:Half-Life; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008136:Longevity / Q000187:drug effects; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D014819:Vitellogenins / Q000235:genetics / Q000378:metabolism*
D015415:Biomarkers; D045166:Estradiol Congeners; D012333:RNA, Messenger; D014819:Vitellogenins; D004997:Ethinyl Estradiol