Expression of 11beta-hydroxysteroid dehydrogenases in bovine follicle and corpus luteum

Abstract

In glucocorticoid target organs, local concentrations of active glucocorticoid are determined by the relative expression of two 11 -hydroxysteroid dehydrogenases (HSDs): bi-directional 11 -HSD type1 (11HSD1) that mainly activates cortisone to cortisol, and dehydrogenase 11 -HSD type2 (11HSD2) that inactivates cortisol to cortisone. In this study, we examined the expression of mRNA encoding these two 11 -HSDs in bovine granulosa cells harvested from preovulatory follicles and corpora lutea (CL). Ovaries were obtained from Holstein cows at a local slaughterhouse. Follicles larger than 10 mm in diameter and CL were dissected and follicular fluid and granulosa cells were taken. Corpora lutea were weighed and their stages were morphologically assessed (stage I, days 1-4; stage II, days 5-10; stage III, days 11-17; stage IV, days 8-20). Follicles were classified into four groups according to their hormonal status (oestradiol (E 2 ): progesterone (P 4 )>1: oestrogen active; E 2 :P 4 <1: oestrogen inactive) and stage of the oestrous cycle (luteal or follicular phase). Total RNA was extracted with phenol-chloroform and subjected to a semi-quantitative RT-PCR for 11HSD1, 11HSD2 and -actin. Concentrations of steroids in follicular fluid were determined by an enzyme immunoassay. In granulosa cells, only 11HSD1 mRNA was detected. There was a negative correlation between the expression of 11HSD1 and the concentration of cortisol in follicular fluid (P<0·05), indicating 11HSD1 may act as a dehydrogenase in the bovine follicle. Both types of 11 -HSDs were expressed in CL. The levels of mRNA for both isozymes were high in stage I and II, and were decreased in stage III CL. In stage IV CL, the expression of 11HSD2 but not 11HSD1 mRNA increased. These results indicate that the bovine granulosa cells and CL express 11HSD1 and 11HSD2, and they may play an important physiological role in the bovine ovary through modulating the local glucocorticoid environment.

11β-Hydroxysteroid dehydrogenase expression and activities in bovine granulosa cells and corpora lutea implicate corticosteroids in bovine ovarian physiology

“…Previous studies of 11bHSD in the bovine ovary have been confined to studies of mRNA expression (Tetsuka et al 2003). This study is the first to document changes in enzyme protein expression and cofactor-dependent enzyme activities across the bovine ovarian cycle in granulosa cells and the early CL.…”

“…In each case, follicular fluid was aspirated from the ovarian follicles and visually assessed for opacity before being discarded. In light of Tetsuka's prior data (Tetsuka et al 2003), only those follicles that were assessed as healthy by visual inspection (i.e. wellvascularised follicles showing no evidence of collapse or leakage and having clear follicular fluid) were used in this study.…”

“…Moreover, this model affords an opportunity to assess hormonal regulation of the 11bHSD enzyme by comparing glucocorticoid metabolism between cells from size-matched bovine follicles in the follicular phase (exposed to high concentrations of oestradiol and inhibin) versus luteal phase (high local concentrations of progesterone and oxytocin). To date, the only published information regarding the bovine ovary is limited to a report of mRNA expression (Tetsuka et al 2003). While this prior report noted differences in the level of expression of 11bHSD1 mRNA between healthy 'oestrogen active' and atretic 'oestrogen inactive' granulosa cells, the primary focus of the study was a comparison of 11bHSD transcript levels between the early, mid and late bovine corpora lutea (CL).…”

Effects of Cortisol on Pregnancy Rate and Corpus Luteum Function in Heifers: An <i>In Vivo</i> Study

“…Access of GCs to GC receptors in target tissues is regulated by two 11β-HSDs, bidirectional 11β-HSD type 1 (11β-HSD1) that mainly converts cortisone to active cortisol [11] and 11β-HSD type 2 (11β-HSD2) that inactivates cortisol to cortisone [12]. Although both 11β-HSDs and GC receptors are expressed in the bovine corpus luteum (CL) [13,14] and endometrium [8] throughout the estrous cycle and early pregnancy [15], the role of GC in regulating CL function is still controversial.Our previous in vitro studies have suggested that cortisol suppresses tumor necrosis factor α (TNFα)-stimulated prostaglandin (PG) F 2α production in endometrial stromal cells [8] and inhibits apoptosis of cultured luteal cells induced by TNFα and interferon-γ (IFNG) [13]. Based on the results of in vitro studies, it seems that cortisol plays a role in preventing excessive uterine PGF 2α production and protecting the CL against apoptosis in nonpregnant cattle [13,16].…”

“…Access of GCs to GC receptors in target tissues is regulated by two 11β-HSDs, bidirectional 11β-HSD type 1 (11β-HSD1) that mainly converts cortisone to active cortisol [11] and 11β-HSD type 2 (11β-HSD2) that inactivates cortisol to cortisone [12]. Although both 11β-HSDs and GC receptors are expressed in the bovine corpus luteum (CL) [13,14] and endometrium [8] throughout the estrous cycle and early pregnancy [15], the role of GC in regulating CL function is still controversial.…”