The thyroids of precociously hypophysectomized chick embryos cease their process of differentiation during the eleventh to twelfth day of incubation. To ascertain whether this process is under the control of the hypophysis, in precociously hypophysectomized embryos (White Leghorn and Wyandotte) on the 12th day of incubation, a hypophysis of eighteen days was transplanted onto the chorio-allantois. The thyroids of the embryos which received the grafts reacquired the morphological and cytological characteristics of the controls after 4 days. The diameter of the follicular light and the width of the epithelial cells increased. The cytomembranes increased, the amount of free ribosomes decreased. Also the colloid chromophobe in the hypophysectomized embryos becomes chromophylic as in the controls.
Referenze Bibliografiche
CORUJO A., MATROLIA L. e MANELLI H. (1976) - Sul differenziamento della tiroide in embrioni di pollo normali e ipofisectomizzati. (In corso di stampa su «Riv. di Biol.»).
FUGO N. W. e WITSCHI E. (1938) - Removal of the hypophyseal primordium in the chick during the second day of incubation, «Acta Biol. Latvica», 73-80.
MARAUD R., AUDINE M. e R. STOLL (1975) - Sur l'existence des relations hypothalamo-hypophysaires chez l'embryon de poulet, «C.R. Soc. Biol.», 169, 923—927.
MESS B., STAZNICKY K. e HAJOS F. (1966) - La differenziazione della ghiandola tiroide e la sua dipendenza dall'ormone tireotropo (TSH) in embrioni di pollo normali e decapitati, «Rass. Neurol. Veg.», 20, 359-374
REYNOLDS E. S. (1963) - The use of lead citrate at high pH as an electron-opaque stain in electron microscopy, «J. Cell. Biol.», 17, 208.
STOLL R., MARAUD R. e SPARFEL A. (1959) - Recherches sur le rôle des u-cytoniembranes dans le développement de la thyroide et dans ses tumeurs, «Arch. Anat. Morph. Exp.», 48, 1-24.
STOLL R., MARAUD R. e LACOURT P. (1961) - L'ultrastructure de la thyroide, «Ann. Endo crinol.», 22, 281-304.
TIXIER A. (1954) - «Compt. Rend. Soc. Biol.», 148, 874-891.
TIXIER-VIDAL A. (1954) - Étude histophysiologique de l'hypophyse anterieur de l'embryon de poulet, «Arch. Anat. micr. Morph. Exp.», 43, 163-186.
Con il contributo del Ministero per i Beni e le Attività Culturali