Evidence that control of fetal thyrotropin secretion is independent of both the fetal and maternal hypothalamus.
Propylthiouracil (PTU) administered to pregnant rats from day 18-21 of gestation caused a significant increase in maternal and fetal thyroid weight and plasma TSH. Fetal encephalectomy on day 18 did not significantly affect basal or PTU-stimulated pituitary-thyroid function. Destruction of the basal hypothalamus in the mother on day 13 or 16 markedly reduced maternal plasma TSH and thyroxine and prevented a PTU-induced increase in thyroid size, but did not affect fetal pituitary-thyroid function. Plasma PRL, was undetectable in both intact and encephalectomized fetuses at 21 days but was increased greater than 6-fold to approximately 2 microgram/ml in the mothers by maternal hypothalamic destruction. We conclude that fetal pituitary-thyroid function in the rat is not dependent on either fetal or maternal hypothalamic TRH.
D000818:Animals; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005333:Fetus; D006651:Histocytochemistry; D007031:Hypothalamus / Q000196:embryology / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal; D011388:Prolactin / Q000097:blood; D011441:Propylthiouracil / Q000494:pharmacology; D051381:Rats; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood
D011441:Propylthiouracil; D011388:Prolactin; D013972:Thyrotropin; D013974:Thyroxine