Ultrastructural Detection of the Onset of Pituitary Thyrotroph Sensitivity to Lowered Thyroid Hormone Concentrations in the Fetal Sheep
作者:
R.A. Perry,
G.H. McIntosh,
P.M. Robinson,
期刊:
Cells Tissues Organs
(Karger Available online 1983)
卷期:
Volume 117,
issue 1
页码: 42-50
ISSN:1422-6405
年代: 1983
DOI:10.1159/000145769
出版商: S. Karger AG
关键词: Pituitary;Thyroidectomy cell;Goitrogen;Fetal sheep;Electron microscopy
数据来源: Karger
摘要:
The goitrogen methylthiouracil was administered orally to pregnant ewes of known gestational ages to induce hypothyroidism in both mother and fetus. Developing pituitary thyrotrophic cells were studied using electron microscopy to detect the earliest gestational age at which morphological changes occurred in response to lowered plasma thyroid hormone concentrations. At 50 days of gestation, the pituitaries of fetuses exposed to the goitrogen were indistinguishable from untreated control glands. However, at 58 days and subsequent ages, ‘thyroidectomy’ cells were observed in pituitaries of all hypothyroid fetuses. These findings indicate that fetal sheep pituitary thyrotrophs are sensitive to lowered thyroid hormone concentrations by 58 days of gestation, suggesting that thyroid-thyrotroph interaction exists at this early stage of developm
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