scholarly journals DEVELOPMENT OF PHENOBARBITAL-SENSITIVE CONTROL MECHANISMS FOR URIDINE DIPHOSPHATE GLUCURONYLTRANSFERASE ACTIVITY IN CHICK EMBRYO LIVER

1972 ◽  
Vol 55 (2) ◽  
pp. 448-456 ◽  
Author(s):  
Brian Burchell ◽  
Geoffrey J. Dutton ◽  
Andrew M. Nemeth
Keyword(s):  
Enzyme Activity ◽  
Chick Embryo ◽  
Organ Culture ◽  
Culture Medium ◽  
Developmental Changes ◽  
Regulatory Mechanisms ◽  
Control Mechanisms ◽  
Uridine Diphosphate ◽  
In Ovo ◽  
Embryo Liver

Uridine diphosphate (UDP) glucuronyltransferase activity in chick liver rises at hatching from near zero to adult levels. This rise will occur prematurely in embryo liver during organ culture. Increase in enzyme activity during organ culture differs with embryo age: in liver from 11-day old embryos it ceases at adult values; in liver from 5-day old embryos it continues to much higher-than-adult levels. Phenobarbital added to culture medium accelerates these rises in enzyme activity and elevates the plateau reached in 11-day embryo liver to that observed in 5-day embryo liver. Kinetic analysis of the changes in enzyme activity induced by phenobarbital during culture suggests that the regulatory mechanisms for enzyme activity are different in 5- and 11-day embryo liver and that these differences reflect developmental changes occurring in ovo.

scholarly journals Studies of tRNAVal isolated from chick embryo liver irradiated in ovo

1975 ◽  
Vol 32 (6) ◽  
pp. 766-767
Author(s):  
L Gyenge ◽  
E Bölöni ◽  
A Benkó ◽  
L D Szabó ◽  
F Joliot-Curie
Keyword(s):  
Chick Embryo ◽  
In Ovo ◽  
Embryo Liver

Development of chick embryo liver during organ culture: Requirement for zinc-insulin

1972 ◽  
Vol 79 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Camillo A. Benzo ◽  
Gabriel de la Haba
Keyword(s):  
Chick Embryo ◽  
Organ Culture ◽  
Embryo Liver

scholarly journals Some properties of the uridine diphosphate glucuronyltransferase activity synthesizing thio-β-d-glucuronides

1973 ◽  
Vol 131 (1) ◽  
pp. 139-147 ◽  
Author(s):  
H. P. A. Illing ◽  
G. J. Dutton
Keyword(s):  
Enzyme Activity ◽  
Phenolic Compounds ◽  
Organ Culture ◽  
Tissue Distribution ◽  
Glucuronic Acid ◽  
Uridine Diphosphate ◽  
Intracellular Location ◽  
Gunn Rats ◽  
Optimum Ph

1. Some properties of the UDP-glucuronyltransferase synthesizing thio-β-d-glucuronides were investigated and compared with those of the enzyme synthesizing the O-glucuronides of analogous phenols. 2. Enzyme activity was generally similar for both classes of substrate in tissue distribution, intracellular location, optimum pH, perinatal development and induction by organ culture or by phenobarbital. 3. Certain differences were noted between the two types of activity in behaviour on storage and on activation, in kinetic behaviour and in distribution between Wistar and Gunn rats; the Gunn rats were not deficient in hepatic UDP-glucuronyltransferase activity towards o-aminothiophenol. 4. These differences are no greater than those exhibited in the synthesis of various O-glucuronides; therefore thiolic substrates could compete in vivo with phenolic compounds for access to the UDP-glucuronyltransferase complex as well as for UDP-glucuronic acid.

scholarly journals Precocious development of UDP-glucuronyltransferase activity in chick-embryo liver after administration of adrenocorticotropic hormone and of certain 11β-hydroxy corticosteroids

1976 ◽  
Vol 158 (2) ◽  
pp. 419-426 ◽  
Author(s):  
J E Leakey ◽  
G J Wishart ◽  
G J Dutton
Keyword(s):  
Chick Embryo ◽  
Pituitary Gland ◽  
Adrenocorticotropic Hormone ◽  
In Ovo ◽  
Synthetic Compound ◽  
Natural Development ◽  
Wide Range ◽  
Embryo Liver ◽  
Precocious Development

1. Precocious development of UDP-glucuronyltransferase (EC 2.4.1.17) and of glucuronidation by endogenous compounds of known chemical composition is reported for the first time. 2. This development occurs precociously in chick-embryo liver after administration to the egg of mammalian adrenocorticotropic hormone, of Synacthen (a synthetic compound possessing adrenocorticotropic activity), or of certain corticosteroids possessing a hydroxy or an oxo group at C-11. 3. Corticosterone-dependent transferase development parallels the rise of infused corticosterone in plasma, but does not require the presence of embryo pituitary in ovo, and is demonstrable in embryo liver explants in vitro. 4. Competence of embryo liver transferase to respond to corticosterone (or dexamethasone) begins over days 13-14, the time of competence to respond to grafted pituitary gland. 5. The transferase appearing after treatment with corticosterone or adrenocorticotropic hormone, like that appearing after pituitary grafting or on natural development and unlike that from the untreated embryo, is markedly activated by membrane-perturbation procedures, suggesting it appears through induction, not activation. 6. Thyroxine and tri-iodothyronine accelerate transferase development after treatment with adrenocorticotropic hormone or corticosteroid to the rate seen after pituitary grafting. 7. A wide range of other hormones and steroids did not obviously influence transferase development in this system. 8. We suggest that grafted pituitary gland evokes precocious transferase development in embryo liver through production of adrenocorticotropic hormone and hence of the active corticosteroids; thyrotropin and thyroxine hasten the process. The role of this mechanism in the natural development of UDP-glucuronyltransferase is discussed.

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