ISSN:
1432-0878
Keywords:
Adenohypophysis
;
Chicken
;
Developmental endocrinology
;
Epithelial differentiation
;
Light and electron microscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Anlagen of the pars distalis (Rathke's pouch), adjacent ectoderm, endoderm, infundibulum and mesenchyme left in situ were put in 3% glutaraldehyde between 1–3 pm and fixed overnight. Epon sections of this material from six White Leghorn, Gallus gallus, embryos fixed at each stage, and of two control partes distales from laying hens of the same flock were examined. At stage 17 (∼12 hours after formation) Rathke's pouch cells were stratified, uninnervated, non-vascularized and stellate, with high nucleo-cytoplasmic ratios and few organelles. Except for lipid inclusions, pouch cells did not appear appreciably different by stage 27, either regionally within the pouch wall or from the adjacent epithelioid cells. Apparent major changes indicative of cytoplasmic maturation by stage 27 included: reduction in number of polysomes; appearance of single-membraned, dumb-bell shaped to rounded, dense granula which were usually in basal position but also in areas of the Golgi apparatus; greater prominence of rough endoplasmic reticulum with cisternae containing dense material, and of the Golgi apparatus, notably with variously dense and/or coated vesicles and material; reduction in lipid inclusions by stage 24. Non-terminating axons in the infundibulum were first seen at stage 27. We found no convincing evidence for any possible morphogenetic or other relationship between the pars distalis and surrounding tissues. “Melanophore-stimulating hormone-activity”, reported to appear on day 5 of incubation, “stored thyroid-stimulating hormone” or pars distalis hormone granula or activities could not be identified. Rathke's pouch and other epithelioid structures may have been secreting, taking up nutrients and/or differentiating, activities which could be important for yolk sac development, nutrition and/or cytodifferentiation, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00222808
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