Chronotypic induction of tyrosine aminotransferase by. cap alpha. -methyl-p-tyrosine. [Rat liver]

Journal Article · Mon Apr 06 04:00:00 EST 1981 · Life Sci.; (United States)

DOI:https://doi.org/10.1016/0024-3205(81)90323-4· OSTI ID:6569045

Cahill, A L; Ferguson, S M; Ehret, C F

..cap alpha..Methyl-p-tyrosine induced hepatic tyrosine aminotransferase activity to different extents depending upon the time of day of administration of the drug. Maximal induction occurred when ..cap alpha..-methyl-p-tyrosine (100 mg/kg) was injected intraperitoneally during the first several hours of the light phase of the daily cycle, but the magnitude of the induction depended on the nutritional state of the animal. Induction was 4- to 5-fold greater in fasting rats. The effect of ..cap alpha..-methyl-ptyrosine on hepatic tyrosine aminotransferase is believed to be mediated by decreases in hypothalamic norepinephrine. This hypothesis was supported by the demonstration that decreasing levels of hypothalamic norepinephrine at times of day when hypothalamic turnover of norepinephrine was greatest resulted in the greatest induction of tyrosine aminotransferase, while lowering hypothalamic norepinephrine at times when turnover was minimal resulted in minimal induction of tyrosine aminotransferase.

• Research Organization: Argonne National Lab., IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6569045
• Journal Information: Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 28:14; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
551000 -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
AMINOTRANSFERASES
ANIMALS
BIOLOGICAL EFFECTS
BODY
CARBOXYLIC ACID ESTERS
DAILY VARIATIONS
DIGESTIVE SYSTEM
ENZYME ACTIVITY
ENZYME REACTIVATION
ENZYMES
ESTERS
GLANDS
INJECTION
INTAKE
INTRAPERITONEAL INJECTION
LIVER
MAMMALS
NITROGEN TRANSFERASES
NOREPINEPHRINE
NUTRITION
ORGANIC COMPOUNDS
ORGANS
RATS
RODENTS
TIME DEPENDENCE
TRANSFERASES
VARIATIONS
VERTEBRATES