Objective: To compare molar and placental tissue insulin-like growth factor-I (IGF-I) levels and IGF-I messenger RNA (mRNA) expression and maternal serum IGF-I levels in molar and normal pregnancies of the same gestational length.
Methods: Tissue and serum total IGF-I were measured by radioimmunoassay, and tissue IGF-I mRNA expression was measured by a solution hybridization technique in samples from seven patients with hydatidiform mole in gestational weeks 8 through 14 and from 12 women with normal placentas undergoing induced abortion during weeks 8 through 12.
Results: Tissue and serum total IGF-I levels and tissue IGF-I mRNA expression were significantly lower in molar pregnancies than in pregnancies with normal placenta.
Conclusion: The lower levels of both IGF-I mRNA and of the IGF-I protein itself in hydatidiform mole indicates that the regulation of expression of IGF-I is on the transcriptional level. This finding may reflect a decreased production of the placental growth hormone variant in molar tissue.