Expression of Androgen Receptor, Estrogen Receptors Alpha and Beta and Aromatase in the Fetal, Perinatal, Prepubertal and Adult Testes of the South American Plains Vizcacha, <i>Lagostomus maximus</i> (Mammalia, Rodentia)

Abstract

Abstract. Androgens and androgen receptor play a critical role in spermatogenesis and fertility in mammals, and estrogens and their receptors contribute to regulation of testicular function through initiation and maintenance of spermatogenesis and germ cell division and survival. However, results from different species are still far from establishing a clear understanding of these receptors in the different cell types from the testis. We analyzed the expression of androgen receptor, estrogen receptors α and β and aromatase protein by immunohistochemistry and real-time PCR, in relation to proliferation followed by the expression of proliferation cell nuclear antigen (PCNA) and germinal identity by VASA protein, in fetal, perinatal, prepubertal and adult testes of Lagostomus maximus, a rodent with sustained germ cell proliferation and an increasing number of OCT-4-expressing gonocytes in the developing ovary. AR expression was restricted to Leydig cells and peritubular cells before sexual maturity, at which point it also became expressed in Sertoli cells. ERα and ERβ were expressed in seminiferous tubules and the interstitium, respectively, in both fetal and prepubertal testes. In adult testes, both ERα and ERβ co-localized in Leydig and peritubular cells. The aromatase enzyme, which converts androgenic precursors into estrogens, was detectable in all developmental stages analyzed and was restricted to Leydig cells. PCNA remained high until sexual maturity. A ndrogens and the androgen receptor (AR) have been shown to play a critical role in normal spermatogenesis and fertility in mammals [1]. The testosterone, responsible for inducing meiosis, postmeiotic development and inhibiting apoptosis in the germ cell, is produced in the testis by the Leydig cells and binds to the AR modulating gene transcription in Leydig, Sertoli, peritubular and germ cells [2]. It has been clearly established that the AR is expressed in Sertoli, Leydig and peritubular cells in the mammalian testis. However, immunodetection of the AR in testicular germ cells is controversial, with reports indicating its detection and absence, although functional AR in germ cells is not essential for spermatogenesis and male fertility in mice [3].Estrogens have been shown to largely contribute to the regulation of testicular function [4,5], acting on the initiation and maintenance of spermatogenesis and on germinal stem cell division and survival [5]. Estrogen action is displayed by means of two different estrogen receptors (ERs), estrogen receptor-alpha (ERα) and estrogen receptor-beta (ERβ), localized in the different testicular cells types. The localization of ERs in testicular cells is not only species-specific but it also varies depending on the type of receptor and the developmental stage of the germ cell [6][7][8][9][10]. In most species analyzed (e.g., human, rat, cat, dog), ERα and ERβ co-localize in spermatogonia, spermatocytes and spermatids as well as in Sertoli, Leydig, and peritubular cells [9,10]. In other species, such as the boar, ERα and ...

An immunohistochemical study on testicular steroidogenesis in the Sunda porcupine (<i>Hystrix javanica</i>)

“…Thus, the Leydig cells can synthesize estrogen and androgen. This result is similar to that of previous studies on other animals such as South American plains vizcachas [18], sika deer [21, 22], humans [7, 8, 26], stallions [13], rams [6], boars [16] and shiba goat [49]. Many previous studies identified localization of this enzyme in other testicular cells, such as Sertoli cells and/or germ cells, in raccoons [39], wild ground squirrels [32], Japanese black bears [38], Japanese raccoon dogs [43], Hokkaido brown bears [44], American black bears [45], northern fur seals [46], mice [37] and rats [30].…”

Seasonal expression of androgen receptor, aromatase, and estrogen receptor alpha and beta in the testis of the wild ground squirrel (Citellus dauricus Brandt)

“…In the boar, ERα was localized in spermatogonia and primary spermatocytes, whereas ERβ immunoreactivity was localized in Sertoli cells. 39 , 40 In the South American Plains Vizcacha fetal and prepubertal testes, 16 ERα and ERβ were expressed in seminiferous tubules and the interstitium, respectively. Yet in adult testes, both ERα and ERβ co-localized in Leydig and peritubular cells.…”

“…The localization of ERs in testicular cells is not only species-specific but also varies depending on the type of receptor and the developmental stage of the germ cell. 16 In most species analyzed, such as human, rat, cat and dog, ERα and ERβ co-localize in spermatogonia, spermatocytes and spermatids as well as in Sertoli, Leydig, and peritubular myoid cells and these locations appeared to change with age in some reports. 17 , 18 In other species, such as the boar, ERα and ERβ localize separately to spermatogonia/primary spermatocytes and Sertoli cells, respectively.…”

The key action of estradiol and progesterone enables GnRH delivery during gestation in the South American plains vizcacha, Lagostomus maximus

“…Its concentration was quantified by absorption at 260nm Table 2. These primers were previously employed in vizcacha (Gonzalez et al 2012, Charif et al 2016. Quantitative measures were performed using a Stratagene MPX500 cycler (Stratagene, California, USA).…”