Eyestalk Content of the Crustacean Hyperglycemic Hormone (CHH) in Palaemon Argentinus Exposed to Currently Used Pesticides, Alone and in Mixtures

BERTRAND, LIDWINA; MEDESANI, DANIEL; AMÉ, M. V.; GONZALEZ, M. F; RODRIGUEZ, ENRIQUE

Montevideo

Congreso; Society of Environmental Toxicology and Chemistry (SETAC) Latin America 15th Biennial Meeting; 2023

SETAC LA

Hyperglycemia is a stress-related mechanism induced in crustaceans by the secretion of crustacean hyperglycemic hormone (CHH) from the X-organ-sinus gland complex. Environmental stressors, including thermal changes, parasitic infections, and pollutants such as pesticides, were identified as responsible for increasing CHH levels. The main goal of the present study was to evaluate the content of CHH in the eyestalks of Palaemon argentinus exposed to current use pesticides (CUPs), alone and in mixture, using enzyme-linked immunosorbent assays (ELISA). Adult organisms were exposed for 96h to the followingtreatments: a- Control (0 μg L-1) b- two concentrations, low (LC) and high (HC), of the following CUPs: b.1- the herbicide metolachlor (M, 3.5 and 70.5 μg L-1); b.2- the insecticide clorantraniliprol (C, 0.002 and 0.04 μg L-1), and b.3- the fungicide epoxiconazole (E, 1.3 and 26.07 μg L-1). Both binary (CE, CM, EM) and ternary (CEM) mixtures were also assayed. For LC exposures, our results showed a significant decrease in CHH levels of organisms exposed to C (0.45±0.05 μg CHH eyetalk-1), CE (0.33±0.04 μg CHH eyetalk-1) and CM (0.41±0.04 μg CHH eyetalk-1), with respect to control (0.65± 0.05 μg CHH eyetalk-1). These results would suggest a significant effect of the insecticide C on CHH levels, which appears to be suppressed in the ternary mixture. However, under HC exposure to the fungicide E (0.47± 0.04 μg CHH eyetalk-1) and its mixture with the other CUPs (CE and EM, with 0.51±0.04 and 0.54±0.04 μg CHH eyetalk-1 respectively) CHH levels decreased significantly when compared to the control group. Moreover, organisms exposed to M and the ternary mixture (CEM) evidenced the lowest CHH levels in their eyestalks, reaching concentrations of 0.36±0.04 and 0.37±0.04 μg CHH eyetalk-1, respectively. Finally, all treatments, except E and ME, showed significant differences in CHH levels when exposure to LC and HC were compared. The significant decrease in CHH concentrations in the eyestalk suggests inhibition of hormone synthesis inexposed organisms and/or the induction of hormone release into the circulating hemolymph. Previous studies indicate that exposure to some pesticides in crustaceans may result in elevated glucose hemolymphatic level and depletion of hepatopancreatic glycogen, due to CHH secretion. Our results represent the first report of CHH in the mentioned South American native species.