Thyroxine treatments in vivo and ultrastructural differentiation of chicken (Gallus gallus) embryo duodenum

Abstract

BREWER, L. M., and T. W. BETZ. 1982. Thyroxine treatments in vivo and ultrastructural differentiation of chicken (Gallus gallus) embryo duodenum. Can. J. Zool. 60: 676-686.Previously, L-thyroxine (L-T4) treatment of 16.5-day-old chicken embryos (approximately stage 42) correlated with a precocious increase in prehatching duodenal alkaline phosphatase specific activity. This paper examines the effects of similar L-T4 treatment on ultrastructural differentiation of the absorptive epithelium. White Leghorn embryos (strain Hyline 934F of Gallus gallus) were given 0.1 mL of saline containing 5-pg doses of either L -T~, or D-T~, or saline vehicle alone through windows in the shell. Untreated windowed and intact unwindowed embryos were additional controls. At the time of treatment (16.5 days) and 24,48, and 72 h later embryos were killed and their duodena were fixed. At least three embryos were examined in each group. Twenty-four hours after treatment stage 43 epithelial cells resembled stage 42 cells. Forty-eight and 72 h following L-T4 treatment stage 44 and 45 embryos showed evidence of increased Golgi and lysosome activity but depletion of lipid droplets and glycogen stores. Control treatments with D -T~ or saline vehicle did not appear to affect epithelial cell ultrastructure as these embryos resembled unwindowed and windpwed control embryos at all stages. BREWER, L. M., et T. W. BETZ. 1982. Thyroxine treatments in vivo and ultrastructural differentiation of chicken ( Gallus gallus) embryo duodenum. Can. J. Zool. 60: 676-686. I1 est prouvC qu'un traitement la L-thyroxine (L-T4) administrC a des embryons de poulet de 16,5 jours (stade 42 environ) entraine une augmentation prCcoce de I'activitC spkcifique de la phosphatase alcaline du duodenum avant I'Cclosion. On examine cette fois les effets d'un traitement a la L-T4 sur la differenciation de l'ultra-structure de 1'CpithClium absorbant. Des embryons de la Leghorn blanche (souche Hyline 934 F de Gallus gallus) ont r e p soit 0,l mL de solution saline contenant des doses de 5 pg de L-T4 ou de D-T~, soit la solution saline seulement, administrC par des fenCtres dans la coquille. Des embryons a coquille trouCe et d'autres A coquille intacte ont aussi semi de tCmoins. Des embryons ont kt6 tuCs et leur duodCnum fix6 au moment du traitement (16,5 jours), d'autres 24, 48 et 72 h aprks le traitement. Au moins trois embryons ont Ct C examinks dans chaque groupe. Vingt-quatre heures aprks le traitement, les cellules CpithCliales de stade 43 ressemblent a celles de stage 42. Quarante-huit heures et 72 h aprh le traitement a la L -T~, les embryons de stade 44 et 45 portent des traces d'une activitC accrue des appareils de Golgi et des lysosomes, mais les gouttelettes de lipide et les rksemes de glycoghe ont diminuk.Chez les embryons traitCs a la D-T4 ou a la solution saline seulement, l'ultra-structure des cellules CpithCliales n'est pas affectke puisque ces cellules restent semblables a celles des embryons tCmoins de tous stades a coquille trouCe ou intacte.[Traduit par le jou...

Thyroxine Treatment and Chicken (Gallus gallus) Embryo Duodenumin vitro

“…During the week preceding hatching, the duodenum undergoes rapid enzymic and structural development (Moog 1950). Recent papers have reviewed duodenal morphogenesis, enzymic development and mucosal cytodifferentiation in chicken embryos (Black 1978, Black and Moog 1Y77, 1978, Brewer and Betz 1979, 1982. These events appear to be controlled by the embryonic adenohypophysis, adrenal glucocorticoids, thyroid hormones, ingested albumen (Moog and Nehari 1954, Moog and Kirsch 1955, Moog and Richardson 1955, Moog 1961, 1962, Hinni and Watterson 1963, Hayes 1965, Dobbins et al 1967, Betz 1968, Bellware and Betz 1970, Mallon and Betz 1970, Struthers 1970, Hart and Betz 1972a, 1972b, Mallon 1972 Hulan and Betz 1973, Betz 1975, Betz and Hart 1977, Black 1978, Black and Moog 1977, 1978, Brewer and Betz 1979.…”