Brain steroid contents in the catfish Heteropneustes fossilis: sex and gonad stage-specific changes

Abstract

Neurosteroids are those which are synthesized in the central nervous system independently of supply by peripheral endocrine glands. In the present study, brain contents of the steroid hormones, estradiol-17β (E(2)), testosterone (T), corticosteroids, and progestins were investigated in both male and female catfish Heteropneustes fossilis in prespawning (vitellogenic) and spawning (post-vitellogenic) phases using ELISA or HPLC. The data show that the measured steroid hormones showed both stage-specific and sex-related variations. Brain E(2) was significantly higher in males in the prespawning phase and in females in the spawning phase. Testosterone was significantly higher in males in comparison with females in the prespawning phase. Cortisol was significantly higher in the prespawning and spawning phases in males than in females. Corticosterone level was low in the brain. 21-deoxycortisol and deoxycorticosterone were significantly higher in the prespawning phase than in the spawning phase. Male brain recorded the highest concentration of deoxycorticosterone. Progesterone (P(4)) was high in the prespawning phase and low in the spawning phase in both sexes. Levels of 17-hydroxy-4-pregnene-3,20-dione and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-DP) and the metabolites of P(4) were the highest in females in the prespawning phase. The stage-specific and sexual differences in the content of the steroids suggest their biosynthesis in the brain, which may have implications in brain functions, in addition to reproductive regulation.

Molecular cloning and characterization of brain and ovarian cytochrome P450 aromatase genes in the catfish Heteropneustes fossilis: Sex, tissue and seasonal variation in, and effects of gonadotropin on gene expression

“…Whereas ovarian aromatases are involved in E 2 synthesis in the ovary for vitellogenesis and feedback actions on the brainpituitary axis for the regulation of gonadotropin secretion and sexual behavior, the brain aromatase is implicated in local production of estrogens for both reproductive and non-reproductive functions like neuroprotection and neurogenesis. In the catfish, high levels of E 2 were reported, indicating a local production in the brain (Chaube and Mishra, 2012).…”

Dimorphic distribution of progestins and cortisol in the brain of Indian stinging catfish Heteropneustes fossilis (Bloch) during different reproductive phases

“…Seasonally breeding teleosts like catfish serve as an excellent model for understanding functional significance of neurosteroids. However, from our previous studies on catfish H. fossilis, it has been reported that catfish brain is the site of steroid biosynthesis as we have reported that key steroid biosynthesizing enzyme 3β-HSD and aromatase is localized in the different regions of the catfish H. fossilis brain (Chaube and Mishra, 2012;Chaube et al, 2015;Mishra and Chaube, 2016;Mishra and Chaube, 2017) and this may be involved in the regulation of reproductive activity through its differential distribution.…”

“…Steroids are mainly secreted by the gonads and cortex region of adrenal gland, regulating diverse processes of the tissues, including gonads, brain, liver and skeletal muscles (Chaube and Mishra, 2012). They cross blood brain barrier due to their lipophilic nature.…”

“…Studies on mammalian and non-mammalian vertebrates have shown that neurosteroids can affect multiple neuroendocrine functions through intracellular receptors, which regulates protein synthesis (Callard et al, 1978;Zohar et al, 2009;Pellegrini et al, 2016;Diotel et al, 2018). Recently, it has been shown that the teleost brain produces neurosteroids, and received global attention (Okubo et al, 2011;Chaube and Mishra, 2012;Chaube et al, 2015;Mishra and Chaube, 2016;Mishra and Chaube, 2017).…”

“…Numerous studies by various researchers reported that steroidogenic enzymes and steroid metabolism (Okubo et al, 2011;Mishra and Chaube, 2012Chaube et al, 2015) exist in various teleost group. Progesterone de novo synthesis in the nervous system and cerebellum has been recognized in studies on humans and several species e.g.…”