Is cortisol a modulator of interferon tau action in the endometrium during early pregnancy in cattle?

Glucocorticoids (GCs) were recently found to be potent modulators of the secretion of uterine prostaglandins (PGs) in ruminants. The aim of the present study was to examine whether GCs may serve as a mediator/modulator of interferon-τ (IFNT) action during early pregnancy in cows. We examined whether IFNT affects cortisol output and expression of GC receptors (NR3C1) and 11β-hydroxysteroid dehydrogenases (enzymes responsible for GC conversion: HSD11B1 and HSD11B2) in bovine endometrium. Endometrial tissues were collected from cyclic and pregnant cows on Days 16–17. Endometrial stromal and epithelial cells were isolated from uteri from cyclic cows in the early luteal phase (Days 2–5). The mRNA and protein expressions of NR3C1, HSD11Bs in endometrial strips and cultured cells were analyzed. Endometrial slices and isolated cells were incubated with cortisone in the presence or absence of IFNT and HSD11B1 activity was evaluated. IFNT increased HSD11B1 activity in endometrial strips and both types of endometrial cells. IFNT influenced NR3C1 and HSD11Bs mRNA and protein expression in epithelial and stromal cells. Expressions of HSD11Bs and NR3C1 mRNA and protein in bovine endometrium were different on Days 16–17 of the estrous cycle compared with early pregnancy. Cortisol changed basal and IFNT-stimulated PGE2 secretion in the bovine endometrium. The overall results suggest that cortisol acts as modulator and/or mediator of IFNT actions in bovine uterus and that IFNT regulates PG secretion by up-regulating local cortisol, resulting in the maintenance of the corpus luteum during early pregnancy in cattle.