Abstract
Gonadotropin-inducible ovarian transcription factor-1 (Giot1) belongs to a family of fast-responsive genes, and gonadotropins rapidly induce its expression in steroidogenic cells of ovaries and testes of rats. Gonadal Giot1 gene expression is regulated by cyclic adenosine monophosphate (cAMP) -dependent protein kinase A pathway, with essential role of orphan nuclear receptor NR4A1 transcription factor (nuclear receptor subfamily 4, group A, member 1). A recent study reports that Giot1 is also expressed in adrenals, however, the mechanism of its regulation in adrenal gland is yet to be identified. Therefore, the aim of this study was to characterise the changes in Giot1 gene expression in male and female rat adrenals using wide range of in vivo and in vitro experimental models. Special emphasis was directed at the Giot1 gene regulation by ACTH and gonadotropin. In our study, we found that ACTH rapidly stimulates Giot1 expression both in vivo and in vitro. However, gonadotropin does not affect the adrenal Giot1 gene expression, presumably due to the low expression of gonadotropin receptor in adrenals. Both testosterone and estradiol administered in vivo had inhibitory effect on Giot1 gene expression in the adrenals of post-gonadectomized adult rats. Further, our studies revealed that the intracellular mechanism of Giot1 gene regulation in rat adrenals is similar to that of gonads. As in the case of gonads, the expression of Giot1 in adrenal gland is regulated by cAMP-dependent signaling pathway with essential role of the NR4A1 transcription factor. The results of our studies suggest that Giot1 may be involved in the regulation of rat adrenocortical steroidogenesis.
Highlights
Steroidogenic cells from ovaries, testes, and adrenal cortex are formed during embryonic development from the same progenitor cells derived from adrenogonadal primordium [1,2]
Using the RNA-seq method, these authors demonstrated that Gonadotropin-inducible ovarian transcription factor-1 (Giot1) expression was highest in rat adrenals compared to other tissues studied and female rats had higher Giot1 expression in adrenals compared to males, whilst sexual dimorphism did not alter Giot1 expression in other organs (Figure 1A)
Since the ovaries have not been included in the Yu et al experiment, we decided to compare the basal level of Giot1 gene expression in ovaries in relation to female adrenals
Summary
Steroidogenic cells from ovaries, testes, and adrenal cortex are formed during embryonic development from the same progenitor cells derived from adrenogonadal primordium [1,2]. These common ontogenetic origins are reflected in the similarity of adrenal cortex and gonads functions, including the hypothalamic–pituitary feedback regulation and production of steroid hormones [3]. It is worth to note that gonadal distribution of Giot overlaps with Ad4- binding protein/steroidogenic factor-1 (Ad4BP/SF-1) and Dax-1 genes, which are essential for sex differentiation and steroidogenesis [10,11]
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