CHARACTERIZATION OF THE INSULIN-LIKE GROWTH-FACTOR (IGF) AXIS IN THE SERUM OF MATERNAL AND FETAL MACAQUES (MACACA-MULATTA AND MACACA-FASCICULARIS)

The insulin-like growth factors (IGFs) are key effecters of fetal grof fth and development which are modulated by serum carrier proteins (IGF binding proteins [IGFBPs]). Studies were performed to evaluate the de velopmental profile of IGFs and IGFBPs in the macaque, an important no nhuman primate model for human development and disease, IGF-I, IGF-II, and IGFBP-3 were studied in the rhesus (Mcaca mulatta) and longtailed (Macaca fascicularis) monkey fetus and dam during the second and thir d trimesters of pregnancy, Serial fetal blood samples were collected b y cardiocentesis every 10 days from gestational day (GD) 90-160, and a t 1 month postnatal age; maternal blood samples were collected at simi lar timepoints, Results indicated that maternal sera IGF-I and IGF-II did not change significantly whereas fetal concentrations of serum IGF -I and IGF-II increased approximately two-fold during the second to th e third trimesters, No significant differences were detected between t he two species, Western-ligand blot analysis revealed predominant IGFB Ps of 45-10 (IGFBP-3) and 28 kDa (IGFBP-1) in both the maternal and fe tal compartments, and Western-immunoblot analysis using a specific ant isera against IGFBP-3 indicated 35-40 and 28 kDa immunoreactive forms, Thus, although IGF-I, IGF-II, and IGFBP-3 remained relatively unaffec ted in maternal sera during this period of gestation, fetal concentrat ions of IGF-I, IGF-II, and IGFBP-3 increased in a developmental profil e similar to the human fetus.