Journal of Clinical Endocrinology & Metabolism, Vol 43, 470-473, Copyright © 1976 by Endocrine Society

ARTICLES

Pituitary hormone levels in plasma of the human fetus after administration of LRH

G Gennser, P Liedholm and J Thorell

The concentrations of hFSH, hLH/hCG, hGH, and hTSH1 were measured in maternal and fetal blood during the second trimester of pregnancy before and after the administration of 10 mug LRH to 9 fetuses. A comparison was performed with 9 control fetuses not receiving LRH. The initial value of hFSH was significantly higher in female than in male fetuses (P less than 0.01) and in both sexes exceeded the low maternal hFSH level. A similar fetomaternal difference existed also for plasma hGH, in contrast to plasma hLH/hCG, which concentration was higher in maternal than in fetal blood LRH did not cause any change of circulating hFSH, hLH/hCG, and hTSH levels in the fetus 10 min after its administration. A rise of fetal hGH levels occurred during the observation time irrespective of LRH administration. In amniotic fluid, the hFSH concentration accorded with that in fetal blood, and the hLH/hCG concentration with that in maternal blood. The fetal plasma levels of these pituitary hormones suggest selective release mechanisms for the various peptides. The causes of the absent response of blood gonadotropin levels to LRH in the fetus are discussed.