کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2800700 1156121 2012 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Pituitary melanotrope cells of Xenopus laevis are of neural ridge origin and do not require induction by the infundibulum
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی علوم غدد
پیش نمایش صفحه اول مقاله
Pituitary melanotrope cells of Xenopus laevis are of neural ridge origin and do not require induction by the infundibulum
چکیده انگلیسی

Classical studies in amphibians have concluded that the endocrine pituitary and pars intermedia are derived from epithelial buccal epidermis and do not 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.


► This study followed early pituitary development in Xenopus laevis.
► Extirpation and grafting studies investigated the role(s) of the brain upon melanotrope differentiation.
► Removal of the presumptive suprachiasmatic area enhanced melanotrope differentiation.
► The infundibulum is not a pituitary inductor.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: General and Comparative Endocrinology - Volume 178, Issue 1, 1 August 2012, Pages 116–122
نویسندگان
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