Tissue-specific expression of messenger ribonucleic acids for insulin-likegrowth factors and insulin-like growth factor-binding proteins during perinatal development of the rat uterus

Insulin-like growth factor (IGF)-I and IGF-II play a number of important ro les in growth and differentiation, and IGF-binding proteins (IGFBPs) modula te IGF biological activity. IGF-l has been shown previously to be essential for normal uterine development. Therefore, we used in situ hybridization a ssays to characterize the unique tissue- and developmental stage-specific p attern of expression for each IGF and IGFBP gene in the rat uterus during p erinatal development (gestational day [GD]-20 to postnatal day [PND]-24). I GF-I and IGFBP-1 mRNAs were expressed in all uterine tissues throughout thi s period. IGFBP-3 mRNA was not detectable at GD-20 but became detectable be ginning at PND-5, and the signal intensity appeared to increase during stro mal and muscle development. IGFBP-4 mRNA was abundant throughout perinatal development in the myometrium and in the stroma, particularly near the lumi nal epithelium. IGFBP-4 mRNA was abundantly expressed in myometrium through out perinatal development. IGFBP-6 mRNA was detected throughout perinatal d evelopment in both the stroma and myometrium in a diffuse expression patter n. IGF-II and IGFBP-2 mRNAs were not detected in perinatal uteri. Our resul ts suggest that coordinated temporal and spatial expression of IGF-I and it s binding proteins (IGFBP-1,-3,-4,-5, and -6) could play important roles in perinatal rodent uterine development.