Expression of 3β-hydroxysteroid dehydrogenase and P450 aromatase in porcine oviduct during the oestrous cycle

Abstract

Steroid hormones regulate the oviductal functions in cyclic pigs. The mRNA and protein steroidogenic enzymes expression 3β-hydroxysteroid dehydrogenase (HSD3B), encoded by HSD3B and P450 aromatase (P450arom), encoded by CYP19, were studied in ampulla and isthmus of pig oviducts during luteal (days 2 - 3, 10 - 11 and 15 - 16) and follicular (days 18 - 20) phase. Expression of HSD3B in ampulla was greater on days 2 - 3, 12 - 13 and 18 - 20 vs 10 - 11 and 15 - 16. In isthmus it was greater on days 2 - 3 vs 10 - 11 and on days 18 - 20 vs 10 - 11 to 15 - 16. Proteins were immunolocalized in epithelial cells of ampulla and isthmus. On days 15 - 16, HSD3B concentration in ampulla was the greatest, in isthmus it was greater on days 15 - 16 vs 12 - 13. The P450arom protein expression was the greatest on days 2 - 3 in ampulla and isthmus and thereafter it gradually declined toward the end of the oestrous cycle. Progesterone concentration (pg • ml 1) in oviductal flushings did not change from days 2 - 3 (960.2 ± 367.2) to 15 - 16 (543.4 ± 235.3), but decreased on days 18 - 20 (154.5 ± 34.8). Androstenedione concentration (pg • ml-1) on days 2 - 3 (726.4 ± 108.4) and 18 - 20 (701.0 ± 59.0), and oestradiol-17β (pg • ml1) levels on days 12 - 13 (104.1 ± 9.6) and 18 - 20 (110.4 ± 14.4) were greater than on other days. This study showed, that expression of mRNA and proteins of steroidogenic enzymes in oviduct of cyclic pigs depends on the stage of the oestrous cycle. This observation suggests ability of porcine oviduct to de novo synthesize steroid hormones.