Gene Expression of 11.BETA.-HSD and Glucocorticoid Receptor in the Bovine (Bos taurus) Follicle During Follicular Maturation and Atresia: The Role of Follicular Stimulating Hormone

Abstract

Abstract. Glucocorticoids modulate ovarian function in cattle. However, their regulatory mechanisms have not been fully elucidated. In the present study, we examined gene expression of two glucocorticoid-metabolizing enzymes, a bidirectional 11β-HSD type 1 (11HSD1) and a dehydrogenase 11β-HSD type 2 (11HSD2), and glucocorticoid receptor (GR) in bovine follicles during follicular maturation and atresia. Granulosa cells (GCs) and theca interna layers (TIs) were harvested from follicles classified as small growing, dominant, preovulatory, early atretic and late atretic follicles. The expression levels of 11HSD1, 11HSD2 and GR mRNA were quantified by real-time PCR. In the healthy follicles, expression of 11HSD1 mRNA increased as follicles matured, both in GCs and TIs. A significant negative correlation was found between the concentration of cortisol in follicular fluid and the level of 11HSD1 mRNA in GCs. The expression of 11HSD2 and GR was either very low or largely unchanged during follicular maturation. In the atretic follicles, a drastic increase in the expression of 11HSD2 was observed both in GCs and TIs. To assess the effect of FSH on the expression of 11HSDs and GR, GCs were cultured with FSH (0-100 ng/ml) for up to 6 days. FSH increased 11HSD1 mRNA in a dose-dependent manner, but not 11HSD2, nor GR. Taken together, these results suggest that developmentally-regulated 11HSD1 plays a pivotal role in modulating the local glucocorticoid environment in maturing bovine follicles. Key words: Bovine, Cortisol, 11β-HSD, Follicle, Glucocorticoid receptor, mRNA (J. Reprod. Dev. 56: [616][617][618][619][620][621][622] 2010) he ovary is a glucocorticoid target organ, and actions of glucocorticoids on ovarian functions have been reported in several species [1]. Glucocorticoids appear to exert both stimulatory and suppressive effects on follicular functions. Glucocorticoids enhance FSH-stimulated progesterone synthesis in cultured granulosa cells (GCs) of rats and cattle [2][3][4][5] and thecal androgen production in cattle [5,6]. Oxytocin production is also stimulated by glucocorticoids in cultured bovine GCs [7]. On the other hand, glucocorticoids have been shown to suppress P450 aromatase (P450arom) activity and decrease the number of LH receptors (LH-R) in rats [2,4], cattle [5] and pigs [8]. These results indicate that glucocorticoid action has to be appropriately regulated to ensure healthy follicular development. The ovary appears to cope with this problem by expressing two glucocorticoid metabolizing enzymes, 11β-HSD type 1 (11HSD1) and type 2 (11HSD2). Research has shown that 11HSD1 is predominantly a reductase that acts as an activator of glucocorticoids (converts inactive glucocorticoids, such as cortisone to cortisol), while 11HSD2 is a dehydrogenase acting as an inactivator [9]. In human and rat preovulatory follicles, GCs predominantly express 11HSD2, which may protect maturing follicles from suppressive effects of glucocorticoids [10][11][12]. The pattern of 11HSD expression appears to be different in ca...

Role of Glucocorticoids in Cystic Ovarian Disease: Expression of Glucocorticoid Receptor in the Bovine Ovary

“…These results correlate with those described by Tetsuka et al [2010], who found that GR mRNA expression did not change throughout the follicular growth in granulosa and theca cells, and increased in atretic follicles. Deprivation of key factors promoting survival, such as estradiol, insulin-like growth factor-1, follicle-stimulating hormone, interleukin-1β and interleukin-6 [Hsu and Hsueh, 1997;Mao et al, 2004;Maeda et al, 2007], or factors that stimulate cell death, such as tumor necrosis factor (TNF)-α, Fas and Fas ligand [Matsuda et al, 2006], are the main cause of apoptosis of granulosa cells.…”

“…GCs act in the ovary and other tissues of the female reproductive system. Also, GCs directly regulate the action of gonadotropins and steroid biosynthesis in the ovary [Kawate et al, 1993;Andersen, 2002;Acosta et al, 2005;Sunak et al, 2007], where GR expression has also been demonstrated [Komiyama et al, 2008;Tetsuka et al, 2010;Park et al, 2012]. GCs also act as potent cytoprotective agents in the ovary, protecting against apoptosis and may play a role in minimizing the damage related to follicle rupture [Whirledge and Cidlowski, 2013].…”

Glucocorticoid metabolism in the bovine cumulus–oocyte complex matured in vitro

“…This is in accordance with the previous findings where FSH has been shown to increase the expression of HSD11B1 in the cultured granulosa cells of rats (Tetsuka et al 1999a) and cattle (Tetsuka et al 2010).…”

“…The presence of these HSD11Bs in the ovary has been reported in various species such as humans (Michael et al 1993, Albiston et al 1994, Michael et al 1997, Tetsuka et al 1997, Ricketts et al 1998, Smith et al 2000, Rae et al 2004, macaques (Fru et al 2006), cattle (Tetsuka et al 2003, Komiyama et al 2008, Tetsuka et al 2010, Amweg et al 2013, pigs (Sunak et al 2007, Webb et al 2008 and rats (Benediktsson et al 1992, Tetsuka et al 1999b, Gomez-Sanchez et al 2009.…”

“…Various ovarian cells have been shown to express HSD11Bs, such as granulosa cells (Tetsuka et al 1997, Ricketts et al 1998, Tetsuka et al 1999b, luteinized granulosa cells (Michael et al 1997, Tetsuka et al 1997, luteal cells (Ricketts et al 1998, Komiyama et al 2008, thecal or thecal interstitial cells (Tetsuka et al 1999b, Tetsuka et al 2010) and ovarian surface epithelial cells (Rae et al 2004). The presence of HSD11Bs in the oocyte or COC has been demonstrated by various methods, but the results are not consistent among the observations.…”