Critical role of nitric oxide in expression of porcine LH receptor at transcription and post-transcription levels

The present study was performed to clarify the involvement of nitric oxide (NO) in the expression of LII receptor in porcine granulosa cells. The gran ulosa cells, prepared from porcine ovarian follicles, were developed in the presence of FSH. LH receptor mRNA was induced to reach a maximal level aft er a 24-h culture with FSH, as determined by semi-quantitative reverse tran scriptase-PCR (RT-PCR). In our previous report (Nishida et al., 2000), we f ound that NO was released from granulosa cells after a 40-48 h culture with FSH. When 200 mu M NO scavenger was added to cultures before the NO releas e (30 h), the content of LH receptor on the cells decreased to 28% that of the control. However, the receptor content was not influenced by addition o f NO scavenger at 46 h, or by 50 mu M NO donor at 30 or 46 h. During transf ormation of mature granulosa cells to luteal cells, LII receptor mRNA was i nduced after a 24-h culture with LI-l, which induction was inhibited by rem oval of endogenous NO. However, the expression was not influenced by additi on of either NO scavenger at 46 h or by NO donor. During the period of thes e treatments, cellular DNA contents were constant. Consequently, the transi ent generation of NO may play a critical role in expression of the LI-I rec eptor at transcription and post-transcription levels.