Subramaniam Kugathas

Pharmaceuticals present in the aquatic environment could adversely affect aquatic organisms. Synthetic glucocorticoids (GC) are used in large quantities as anti-inflammatory drugs and have been reported to be present in river water. In order to assess the impact of environmental concentrations of GCs, an in vivo experiment was conducted with adult fathead minnows. Fish were exposed to 0.1 μg/L, 1 μg/L, or 10 μg/L beclomethasone dipropionate (BCMD) via a flow-through system over a period of 21 days. Similar duplicate tanks served as control, with no chemical added. There was a concentration-related increase in plasma glucose concentration and a decrease in blood lymphocyte count. Induction of male secondary sexual characters and a decreasing trend in plasma vitellogenin (Vtg) concentrations in female fish were observed with increasing exposure concentration of BCMD. Expression profiles of selected genes (phosphoenolpyruvate carboxykinase - PEPCK, glucocorticoid receptor - GR, and Vtg) in liver also demonstrated concentration-related effects at all three tested concentrations. The results suggest that GCs could cause effects in lower micrograms per liter concentrations that could be environmentally relevant for total GCs present in the environment. Therefore, studies to determine the environmental concentrations of GCs and no effect concentrations are needed to assess if GCs pose a risk to the aquatic environment.

Human pharmaceuticals have been shown to be entering the aquatic environment in quantities that may produce adverse effects to aquatic organisms. This paper investigates the impacts of synthetic glucocorticoids (GCs), which are used in large amounts as anti-inflammatory drugs, on fish. Mammalian cell lines were transiently transfected with trout corticosteroid receptors (GR1, GR2, and MR) and the transactivation abilities of ten of the most prescribed GCs in the UK were measured in vitro. They showed significantly higher activity with GR2 than with GR1. In order to assess any impacts in vivo, adult fathead minnows were exposed to either 1 μg prednisolone/L or 1 μg beclomethasone dipropionate/L for 21 days. Plasma glucose concentrations were increased and leucocytes were reduced significantly in GC-exposed groups compared to the control group. In another experiment, fish were exposed to three different concentrations of Beclomethasone dipropionate and a dose-dependent increase of plasma glucose was found. The results suggest that low concentrations of synthetic GCs present in water could cause adverse effects on fish. Therefore, quantification of GCs in the aquatic environment and the effects of GCs at environmentally relevant concentrations are required in order to determine if GCs pose a threat to wild fish populations.