Plasma calcium as a surrogate measure for vitellogenin in fathead minnows (Pimephales promelas)

Numerous reports have demonstrated the vitellogenic response of fish exposed to estrogenic compounds in the aquatic environment. A strong correlation has been shown to exist between plasma vitellogenin and plasma calcium concentrations in salmonid fish. This study examines the relationship between plasma vitellogenin and calcium in a cyprinid fish, the fathead minnow (Pimephales promelas), which is a species commonly used to monitor water quality. Plasma vitellogenin was determined after exposure of male and female fish to proprietary pharmaceutical estrogens using an enzyme-linked immunosorbent assay (ELISA) developed specifically for fathead minnows. Plasma calcium was determined by flame atomic absorption spectroscopy (AA). This study demonstrated significant (P < 0.05) linear correlations between plasma vitellogenin and plasma calcium for males (r2 = 0.70), females (r2 = 0.83), and males and females combined (r2 = 0.06), showing that plasma calcium could be an indirect measure of vitellogenin present in fathead minnows. Some of the limitations and advantages identified through these studies are discussed.