Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/43190
Citations
Scopus Web of Science® Altmetric
?
?
Type: Journal article
Title: Hypothalamic input is required for development of normal numbers of thyrotrophs and gonadotrophs but not other anterior pituitary cells in late gestation sheep
Author: Szarek, E.
Farrand, K.
McMillen, I.
Young, I.
Houghton, D.
Schwartz, J.
Citation: Journal of Physiology-London, 2007; 586(4):1185-1194
Publisher: Blackwell Publishing Ltd
Issue Date: 2007
ISSN: 0022-3751
1469-7793
Statement of
Responsibility: 
Eva Szarek, Kirsten Farrand, I. Caroline McMillen, I. Ross Young, Daniel Houghton and Jeffrey Schwartz
Abstract: To evaluate the hypothalamic contribution to the development of anterior pituitary (AP) cells we surgically disconnected the hypothalamus from the pituitary (hypothalamo-pituitary disconnection, HPD) in fetal sheep and collected pituitaries 31 days later. Pituitaries (n = 6 per group) were obtained from fetal sheep (term = 147 ± 3 days) at 110 days (unoperated group) of gestation and at 141 days from animals that had undergone HPD or sham surgery at 110 days. Cells were identified by labelling pituitary sections with antisera against the six AP hormones. Additionally, we investigated the colocalization of glycoprotein hormones. The proportions of somatotrophs and corticotrophs were unchanged by age or HPD. Lactotrophs increased 80% over time, but the proportion was unaffected by HPD. Thyrotrophs, which were unaffected by age, increased 70% following HPD. Gonadotrophs increased with gestational age (LH+ cells 55%; FSH+ cells 19-fold), but this was severely attenuated by HPD. We investigated the possible existence of a reciprocal effect of HPD on multipotential glycoprotein-expressing cells. Co-expression of LH and TSH was extremely rare (< 1%) and unchanged over the last month of gestation or HPD. The increase of gonadotrophs expressing FSH only or LH and FSH was attenuated by HPD. Therefore, the proportions of somatotrophs, lactotrophs and corticotrophs are regulated independently of hypothalamic input in the late gestation fetal pituitary. In marked contrast, the determination of the thyrotroph and gonadotroph lineages over the same time period is subject to complex mechanisms involving hypothalamic factors, which inhibit differentiation and/or proliferation of thyrotrophs, but stimulate gonadotrophs down the FSH lineage. Development of a distinct population of gonadotrophs, expressing only LH, appears to be subject to alternative mechanisms.
Keywords: Hypothalamo-Hypophyseal System; Pituitary Gland, Anterior; Hypothalamus; Fetus; Animals; Sheep; Follicle Stimulating Hormone; Luteinizing Hormone; Thyrotropin; Cell Count; Fetal Development; Pregnancy; Female; Gonadotrophs; Thyrotrophs
Description: Copyright © 2008 The Physiological Society.
RMID: 0020075633
DOI: 10.1113/jphysiol.2007.141523
Published version: http://jp.physoc.org/cgi/content/abstract/586/4/1185
Appears in Collections:Molecular and Biomedical Science publications

Files in This Item:
There are no files associated with this item.


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.