Expression of Messenger Ribonucleic Acids of Luteinizing Hormone Receptor, P 450 17 α-Hydroxylase and P 450 aromatase in Isolated Granulosa, Theca Interna and Theca Externa Layers of Chicken Ovarian Follicles During Follicular Growth

摘要

The present study was conducted to investigate the association of luteinizing hormone receptor (LHR) mRNA expression with follicular growth and steroidgenesis in the ovarian follicles of laying chickens. Levels of LHR mRNA of granulosa, theca internaand theca externa layers of the preovulatory follicles were determined by Northern hybridization in relation to mRNA expression of P 450 17 α-hydroxylase/17, 20-lyase (P 450 c 17) and P 450 aromatase (P 450 arom). LHR mRNA was clearly detected in the granulosa layers of larger follicles, whereas little mRNA of P450 17 and P450 arom was observed. On the other hand, little LHR mRNA was detected in the theca interna and external layers of any follicles, whereas P450 c l7 mRNA and P 450 arom mRNA expression was localized to the theca interna and externa layers of the follicles, respectively. These changes during follicular development suggest that progesterone production in the granulosa layer is induced by LH via the LHR and production of subsequent metabolites (androgen and estrogen) in the theca interna and externa layers is independent upon regulation by LH.