Correlation between ovarian steroidogenesis and beta-endorphin in the Lizard Uromastyx acanthinura: Immunohistochemical approach.

Abstract

Abstract:In Mammals, opioid peptides are involved in various physiological processes including the reproductive function. The knowledge of the distribution of β-endorphin, one of opioid peptides in Reptiles ovaries is very limited. Therefore, the present study used the lizard ovarian follicles to further elucidate the role of this peptide in steroidogenesis. In Uromastyx acanthinura, the localization of both this peptide and sex steroid hormone was investigated by the immunohistochemical approach. This technique was used to evaluate the distribution of these substances and their relationship. The β-endorphin is strongly distributed in the granulosa cells and oocyte cytoplasm of the previtellogenic follicles in sexually quiescent lizards (winter) when steroidogenesis was interrupted. In spring, the signal became weak, or even absent, in the vitellogenic and previtellogenic follicles. The granulosa cells of the previtellogenic follicles showed an important synthesis of 17β-estradiol. Females that did not undergo in vitellogenesis in spring showed the same profile than quiescent females of winter. These findings represent the first evidence of the presence of β-endorphin in the ovary of this lizard. The seasonal variations observed in the reproductive cycle suggest that this opioid peptide is involved in the modulation of seasonal steroidogenesis.

Sex steroid receptors in the ovarian follicles of the lizard Sceloporus torquatus

“…(Barbosa-Moyano et al, 2020). ER, and PR presence was not related to the sex steroid concentrations, as reported in the lizard U. acanthinura (Hammouche et al, 2017).…”

“…In the previtellogenic phase, ERα in the small cells could be associated with the proliferative activity to differentiate in a polymorphic granulosa (Kocanova et al, 2010;Hamilton et al, 2017). Also, its presence in the cytoplasm of the pyriform cells may indicate their role in the estrogen stimulation synthesis and secretion in previtellogenic follicles (Hammouche et al, 2017;Fuentes and Silveyra, 2019), inducing aromatase activity at the beginning of the reproductive season (Tripathy and Rai, 2017). This steroidogenic capacity has been observed in the granulosa cells of previtellogenic and early vitellogenic follicles in S. torquatus (unpublished data).…”

“…In the turtle Chrysems picta, PRA expression inhibits VTG synthesis (Duggan and Callard, 2003) whereas PRB promotes it (Giannoukos and Callard, 1995). In the preovulatory stage, PR presence can regulate ovulation and caspase 3 activity (Shao et al, 2003;Hammouche et al, 2017). Therefore, the differences in the events may be mediated by each receptor in the different species.…”

Immunolocalization of hepatic estrogen and progesterone receptors in the female lizard Uromastyx acanthinura

“…In U. acanthinura female, our previous research confirmed the seasonal ovarian activity which running from Spring until Summer and the existence of one ovulatory clutch [1]. Several aspects of endocrine control of vitellogenesis have been observed in female [32][33][34][35][36], and male treated with 17b-estradiol obtained the ability to produce vitellogenin [37]. In order to determine the estrogen receptor subtypes and the progesterone receptor isoforms involved in the regulation of the synthesis of vitellogenin in U. acanthinura, we analyzed the presence of estrogen and progesterone receptors in the liver of wild females and females treated with 17b-estradiol using an immunohistochemical method.…”

“…A control of specificity consisted in omitting the primary antiserum step to test non-specific binding of secondary antibody to the tissue was performed. The primary antibodies were also tested in the U. acanthinura [35,38] and the rat Psammomys obesus ovaries [39].…”