Protein synthetic rate in the sheep placenta in vivo: the influence of insulin.
The metabolic gradient between the placenta and maternal tissues is large when expressed as fractional protein synthesis rate; the half-life of the mixed placental proteins is one-fifth of these in the maternal liver, but a little longer than those of the fetal liver and heart. This high turnover rate provides the priority of the uptake of the feto-placental unit for nutrients, to satisfy the genetic growth potential, enabling equivalent weights of the conceptus to take up amino acids in greater quantities than the maternal liver, the adult organ with the highest protein synthetic rate. The results suggest that fractional synthesis rate of the placental proteins was increased when fetal plasma insulin concentrations were raised. Should this enhancement of protein synthetic rate occur in the human subject, it might be responsible for the heavy placentae found in diabetic subjects whose blood sugar is uncontrolled, and account for their apparently large functional capacity.
D000818:Animals; D005260:Female; D007328:Insulin / Q000494:pharmacology*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000096:biosynthesis*; D012756:Sheep
D007328:Insulin; D011257:Pregnancy Proteins