Dual actions of progesterone on uterine leiomyoma correlate with the ratio of progesterone receptor A:B.
BACKGROUND
It has been suggested that progesterone down-regulated the levels of insulin-like growth factor-I (IGF-I). The present study was conducted to elucidate whether progesterone affects IGF-I mRNA through progesterone receptor B(PRB) mRNA in leiomyoma.


METHODS
Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to measure the level of progesterone receptor A (PRA), PRB, and IGF-I mRNA in 21 patients with uterine leiomyoma, and six pairs of matching leiomyomas and adjacent myometria were obtained in the secretory phase.


RESULTS
The ratios of PRA/PRB mRNA were positively correlated with the IGF-I mRNA levels in leiomyoma from women in the secretory phase (r = 0.732, p = 0.002 < 0.01), whereas the correlation between the level of PRB and IGF-I mRNA in leiomyomas was negative (r = -0.573, p = 0.025 < 0.05). The levels of PRA, PRB, and IGF-I mRNA were significantly higher in leiomyomas than in adjacent myometria.


CONCLUSIONS
The progesterone may down-regulate IGF-I expression through PRB, and PRA appears to inhibit this function of progesterone by inhibiting the transcription of PRB; thus, the action of progesterone on leiomyoma growth may depend on different ratios of PRA and PRB.
Ying
Zhao
Z
Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, People's Republic of China.
Weiyuan
Zhang
Z
D000328:Adult; D015536:Down-Regulation; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics; D007889:Leiomyoma / Q000378:metabolism*; D008875:Middle Aged; D009215:Myometrium / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011980:Receptors, Progesterone / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014594:Uterine Neoplasms / Q000378:metabolism*
D012333:RNA, Messenger; D011980:Receptors, Progesterone; C101118:progesterone receptor A; C097314:progesterone receptor B; D011374:Progesterone; D007334:Insulin-Like Growth Factor I