Thyroid hormone relationships in the fetal and newborn lamb

H. Mathur, B. L. Brown, E. J. Krane, A. L. Thomas, P. W. Nathanielsz

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Plasma thyroxine (T4) and reverse triiodothyronine (rT3) concentrations have been measured in chronically catheterised sheep fetuses during the last third of gestation. In some animals T4 and rT3 concentrations fell before delivery but there was no change in the T4/rT3 ratio. In several serially sampled fetuses a small rise in plasma triiodothyronine concentration has been demonstrated in the days preceding delivery. Infusion of cortisol to fetuses commencing at 130 days of gestation (term 147 days) with the simultaneous administration of progesterone to delay labor resulted in changes in T4 and rT3 concentrations which were similar to those normally seen at term. The nature of the changes in the peripheral metabolism of T4 around the time of birth are discussed.

Original languageEnglish (US)
Pages (from-to)138-144
Number of pages7
JournalBiology of the Neonate
Issue number3-4
StatePublished - 1980
Externally publishedYes

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Developmental Biology


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