Insulin‐like growth factor‐1 stimulates amino acid uptake by the cultured human placental trophoblast

摘要: Amino acid uptake by the human placenta is known to occur via several transport mechanisms. However, regulation extracellular factors has received relatively little attention. A recent report this laboratory characterized of α-aminoisobutyric (AIB) stimulated insulin in cultured placental trophoblast The current study evaluated effect insulin-like growth factor-1 (IGF-1) on AIB trophoblasts. Na+-dependent was significantly IGF-l a time-dependent manner, as early 30 min after hormone exposure. maximum at 2–4 hr continuous exposure and stimulation dependent upon IGF-1 concentration approaching maximal 50 ng.ml−1. inhibited increasing concentrations α-(methylamino)isobtyric (MeAIB). Approximately 75% basal (unstimulated) MeAIB. IGF-1-stimulated increment above completely increased yelocity but not Km. Using equimolar concentrations, greater with then IGF-2. Stimulation IGF-1, insulin, anit-IGF-1 receptor antibody, indicating mediation receptor. H7, nonspecific inhibitor serine-threonine kinase, IGF-1-dependent uptake. In addition, calphostin C (a specific protein kinase C), H89 A), action. This further characterizes regulated amino trophoblasts demonstrates that component physiologic IGF-1. © 1995 Wiley-Liss Inc.