301 Somatomedin-c (sm-c) Levels in Fetal Sheep Are Independent of Serum Placental Lactogen Levels

Abstract

The factor(s) regulating fetal growth remain obscure and classic hormones appear not to be involved. Fetal size correlates with fetal SM-C levels; however, fetal growth hormone appears to have no effect either on fetal SM-C or fetal growth. Placental lactogen has been suggested as a modulator of fetal somatomedins. To assess this possibility in the sheep model, time-dated pregnant ewes with singleton fetuses (n=7) underwent fetal arterial catheterization at 111±3 d of gestation (term=150 d). Daily blood samples were obtained from each fetus until parturition or death. (Mean survival=20 d). Serum samples were assayed for both placental lactogen and SM-C. There was no correlation between placental lactogen and SM-C during the study period (r=.03, n=82). A second group of fetuses (n=5) underwent single umbilical artery ligation at 111±3 d of gestation. This procedure results in markedly elevated levels of placental lactogen in the fetus. Chronically catheterized animals were sampled daily and samples were assayed for both placental lactogen and SM-C. Despite the increased plasma placental lactogen levels in these single umbilical artery ligated fetuses, there was no demonstrable correlation between plasma placental lactogen and SM-C concentrations (r=.03, n=66).Conclusion: Somatomedin-C levels in fetal sheep are independent of serum placental lactogen levels during the third trimester.

DOI: 10.1203/00006450-198504000-00331

Cite this paper

@article{Polk1985301S, title={301 Somatomedin-c (sm-c) Levels in Fetal Sheep Are Independent of Serum Placental Lactogen Levels}, author={Daniel H. Polk and Robert Lam and John P. Newnham and Calvin J. Hobel and Delbert A. Fisher}, journal={Pediatric Research}, year={1985}, volume={19}, pages={161A-161A} }