Effects of atrazine on the growth adaptability of yearling lizards (Eremias argus) under a perspective of global warming scenario.

Atrazine is an endocrine disruptor widely present in environment and poses potential threats to ecosystem security. However, studies regarding its impact on reptiles remain limited, particularly under climate warming. This study investigated the effects of atrazine and warming on the growth of yearling lizard (Eremias argus). Lizards were exposed to environmentally relevant but predicted worst-case dose of atrazine (0 and 4 mg/kg) at controlled or warmed conditions for eight weeks. Results revealed that both atrazine and warming adversely affected growth of yearlings, with atrazine identified as the main inhibitory factor. Atrazine significantly reduced the weight and body length growth rate of yearlings irrespective of temperature. Biochemically, atrazine exposure induced oxidative stress and damage in the brain and liver of yearlings, while simultaneously decreasing plasma growth hormone levels and disrupting thyroid hormone homeostasis. Furthermore, the expression of key genes involved in the growth hormone/insulin-like growth factor (GH/IGF) axis (ghr, igf1) and the hypothalamic-pituitary-thyroid (HPT) axis (tg, trα, trβ) were down-regulated. These findings may be the primary mechanisms underlying the observed growth inhibition in yearlings caused by atrazine. Warming was not the main inhibitory effect on yearling growth. However, under ongoing climate warming scenarios, its combined with atrazine exposure may increasingly constrain lizard growth and potentially translating into maladaptation in population-level.