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Pituitary melanotrope cells of Xenopus laevis are of neural ridge origin and do not require induction by the infundibulum.
MedLine Citation:
PMID:  22569169     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Classical studies in amphibians have concluded that the endocrine pituitary and pars intermedia are derived from epithelial buccal epidermis and require the infundibulum for their induction. These studies also assumed that the pituitary is not subsequently determined by infundibular induction. Our extirpation, auto-transplantation and immunohistochemical studies with Xenopus laevis were initiated to investigate early presumptive pituitary development. These studies were conducted especially with reference to the pars intermedia melanotrope cell's induction, and its production and release of α-melanophore stimulating hormone (α-MSH) from the precursor protein proopiomelanocortin (POMC). Auto-transplantation studies demonstrated that the pituitary POMC-producing cells are determined at a stage prior to pituitary-infundibular contact. The results of experiments involving the extirpation of the presumptive infundibulum also indicated that the infundibulum is not essential for the differentiation of POMC-producing cells. We also demonstrated that early pituitary development involves adherence to the prechiasmatic area of the diencephalon with the pituitary placode growing in a posterior direction toward the infundibulum where contact occurs at Xenopus stage 39/40. Overall, our studies provide a model for early tissue relations among presumptive pituitary, suprachiasmatic nucleus, pars tuberalis and infundibulum during neurulation and later neural tube stages of development. It is hypothesized that the overlying chiasmatic area suppresses pituitary differentiation.
Authors:
Gerald W Eagleson; Martijn M Selten; Eric W Roubos; Bruce G Jenks
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-4-30
Journal Detail:
Title:  General and comparative endocrinology     Volume:  -     ISSN:  1095-6840     ISO Abbreviation:  -     Publication Date:  2012 Apr 
Date Detail:
Created Date:  2012-5-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370735     Medline TA:  Gen Comp Endocrinol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier Inc. All rights reserved.
Affiliation:
Dept. Cellular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Faculty of Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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