Insulin-like growth factor 1 receptor mRNA expression and autophosphorylation in human myometrium and leiomyoma.

Uterine leiomyomas are the most common tumors of the genital tract. Growth factors seem to be implicated in the development of leiomyoma. The aim of this study was to determine insulin-like growth factor 1 receptor (IGF-1-R) mRNA levels and IGF-1-R tyrosine kinase activity in normal myometrium and leiomyoma. Plasma membranes of myometrium and leiomyoma of 14 women subjected to hysterectomy were prepared, and samples were incubated in the absence or presence of recombinant human IGF-1 to assess the tyrosine kinase activity (Western blot). Reverse-transcriptase polymerase chain reaction with specific primers for IGF-1-R was used to determine IGF-1-R mRNA levels. IGF-1-R mRNA levels in myometrium (0.8216 +/- 0.096) and in leiomyoma (0.7905 +/- 0.136) were not statistically significantly different (p = 0.648). The degree of IGF-1-R autophosphorylation stimulated by recombinant IGF-1 was not different in myometrium (1.020 +/- 0.120) and leiomyoma (1.620 +/- 0.656) either (p = 0.075). There was no difference in IGF-1-R expression and IGF-1-R autophosphorylation between normal myometrium and leiomyoma.