Stress and sex determination in fish: from brain to gonads

Abstract

Fish present remarkable malleability regarding gonadal sex fate. This phenotypic plasticity enables an organism to adapt changes in the environment by responding with different phenotypes. The gonad and the brain present this extraordinary plasticity. These organs are involved in the response to environmental stressors to direct the gonadal fate, inducing sex change or sex reversal in hermaphroditic and gonochoristic fish, respectively. The presence of such molecular and endocrine plasticity gives this group a large repertoire of possibilities against a continuously changing environment, resulting in the highest radiation of reproduction strategies described in vertebrates. In this review, we provide a broad and comparative view of tremendous radiation of sex determination mechanisms to direct gonadal fate. New results have established that the driving mechanism involves early response to environmental stressors by the brain plus high plasticity of gonadal differentiation and androgens as by-products of stress inactivation. In addition to the stress axis, another two major axes – the hypothalamic-pituitary-gonadal axis and the hypothalamic-pituitary-thyroid axis, which are well known to participate in the regulation of reproduction – have been proposed as reinforcing the brain-gonadal interrelationships in the fate of the gonad.

Does stress make males? An experiment on the role of glucocorticoids in anuran sex reversal

“…Proposed alternative mechanisms (none of which are mutually exclusive) are the cellular calcium and redox regulation (Castelli et al, 2020;Mukai et al, 2022), epigenetic processes (Shao et al, 2014;Zhang et al, 2022), thyroid hormones (Castañeda-Cortés & Fernandino, 2021;Hayes, 1998;Sun et al, 2016), and the energy limitation hypothesis (Geffroy, 2022).…”

Gonadal Transcriptome Analysis and Sequence Characterization of Sex-Related Genes in Cranoglanis bouderius

“…In various vertebrates, dozens of effector pathways and genes involved in sex determination and gonadal development have been identified, including pathways involved in the Sox [ 33 ], Dmrt [ 34 ], Hox [ 35 ], and Wnt [ 36 ] gene families, as well as genes such as Sox9, Sox3, DAX1, AMH, Dmrt1, and Fgf9. The current research has demonstrated that gonadogenesis and development in fish are also co-regulated by these genes [ 37 , 38 ]. We performed a functional analysis of the DEGs, based on the known sequences in the database, and discovered that the DEGs were significantly enriched in the “reproductive process”, “ RNA modification”, “amide biosynthetic process”, “lipid metabolic process”, and “peptide transport processes”.…”

Allometric model of brain morphology of Hemiculter leucisculus and its variation along climatic gradients

“…From an evolutionary perspective, organisms acclimatized themselves to different environments (Kotrschal et al, 1998). As a very important sensory organ with high plasticity (Castañeda‐Cortés & Fernandino, 2021; Dunlap et al, 2019; Noreikiene et al, 2015), the brain plays an important role in fitting organisms to their environments (Hall & Tropepe, 2020; Kotrschal et al, 2017; Schulz‐Mirbach et al, 2016). However, studies on the brain of the Hemiculter leucisculus brain mainly focus on its morphological description (Lu & Li, 1996), but do not explore how the brain changes along the environmental gradients.…”