Objective: Uterine leiomyomas are the most common pelvic tumors, occurring in one of four women, and they represent the single most common indication for hysterectomy. The genesis and growth-promoting factors responsible for their development are poorly understood. We speculate that growth hormone may play a role in the initiation of these tumors; women with acromegaly have a higher incidence of leiomyomas and growth hormone promotes uterine growth in rats, with or without the addition of estradiol. We evaluated the presence of growth hormone receptor messenger ribonucleic acid in the human uterus and leiomyomas to investigate whether growth hormone might act directly rather than by hepatic generation of insulin-like growth factor-I.
Study design: Paired samples of leiomyomas and adjacent normal myometrium from nine premenopausal women (32 to 52 years old) were collected at surgery. Three patients received a gonadotropin-releasing hormone agonist for 3 months before the surgical procedure; six did not receive any adjuvant therapy. We used a digoxigenin-labeled oligoprobe sharing no homology to the growth hormone-binding protein or to the prolactin receptor, to investigate whether growth hormone receptor messenger ribonucleic acid was present in tissue sections or amplified complementary deoxyribonucleic acid from leiomyoma and the surrounding myometrium.
Results: The ratios of growth hormone receptor/reduced glyceraldehyde-phosphate dehydrogenase in leiomyomas and the surrounding myometrium as assessed by densitometry analysis of polymerase chain reaction products were similar and were not altered by gonadotropin-releasing hormone agonist treatment. In situ hybridization localized the growth hormone receptor messenger ribonucleic acid to the nuclei and cytoplasm of leiomyoma and myometrium.
Conclusion: The presence of growth hormone receptor messenger ribonucleic acid suggests that the human uterus is a target tissue for growth hormone action. Future investigations are needed to investigate further the role of growth hormone in the development of leiomyomas.