Interference of an atrazine commercial formulation with the endocrine control of ovarian growth exerted by the eyestalks

Abstract

Atrazine is currently one of the most used herbicides worldwide. We tested the possible effect of the widely used herbicide atrazine on the endocrine control of ovarian growth exerted by the neurohormones secreted at the eyestalk of the estuarine crab Neohelice granulata. For this, both in vivo and in vitro assays were carried out. The in vivo assay comprised the exposure for 1 month to 3 mg/L of a commercial formulation containing 90% of atrazine as active ingredient (Gesaprim 90 WDG®, Syngenta) on three categories of females: intact, ablated of one eyestalk, and ablated of both eyestalks. At the end of the assay, only the intact females showed a significant (p < 0.05) decrease in both content of vitellogenic ovarian proteins and proportion of vitellogenic oocytes, compared to a concurrent control. The results of the in vitro incubation of ovarian pieces with the eventual addition to the incubation medium of eyestalk tissue and/or atrazine at 3 mg/L showed a significant (p < 0.05) decrease in the proportion of vitellogenic oocytes only when atrazine and eyestalk tissue were added. Taken together, these results strongly suggest that the assayed atrazine formulation may act as an endocrine disruptor at the eyestalk level, by altering the normal secretion of some eyestalk hormone, therefore inhibiting ovarian growth.

Effects of the Herbicide Atrazine on Crustacean Reproduction. Mini-Review

“…Asterisk and dot indicate significant differences ( p < 0.05) with respect to control and the lowest concentration, respectively; control male data are also included for comparative purposes. From Silveyra et al (2019) . (C) Proportion of sex in early juveniles of Cherax quadricarinatus exposed during 4 weeks.…”

“…At the end of the assay, only the intact females showed a significant ( p < 0.05) decrease in both the content of vitellogenic ovarian proteins and the proportion of vitellogenic oocytes, compared to the concurrent controls. Moreover, through in vitro assays made on the same species, a decrease in the proportion of vitellogenic oocytes was observed when atrazine was added to ovarian explants co-incubated with eyestalk tissue, but not when added to ovarian explants alone, suggesting that atrazine exerts an impairment on the secretion and/or action of one or more eyestalk neurohormones controlling ovarian growth ( Silveyra et al, 2019 ).…”

Endocrine-Disrupting Compounds: An Overview on Their Occurrence in the Aquatic Environment and Human Exposure

“…In many cases, the interaction of pesticides with the hormonal (endocrine) system of wildlife has led to impaired reproduction and gradual population decline of certain species [211]. It has several consequences on the endocrine system such as demasculinization and feminization of gonads [194] of male vertebrates, control of ovarian growth exerted by the neurohormones secreted at the eyestalk of the crab Neohelice granulata [212], and long-term histofunctional changes in the thyroid gland on the crocodilian specie of C. latirostris during embryonic development [213]. The endocrine-disrupting activity of these pesticides and their metabolites (e.g., dialkyl phosphates) has been observed in different animals.…”