Tumor-promoting phorbol ester amplifies the inductions of tyrosine aminotransferase and ornithine decarboxylase by glucocorticoid

Journal Article · Tue Apr 21 00:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00382a041· OSTI ID:5596219

Kido, H; Fukusen, N; Katunuma, N

In adrenalectomized rats, the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) markedly enhanced the inductions of tyrosine aminotransferase (TAT) and ornithine decarboxylase by glucocorticoids, even with sufficient concentration of glucocorticoids to have a maximal effect, whereas it had no effect on TAT activity and increased ornithine decarboxylase activity only slightly in the absence of glucocorticoids. Phorbol derivatives and components of TPA such as 4..beta..-phorbol, phorbol 12-tetradecanoate, phorbol 13-acetate, and 4-O-methylphorbol 12-tetradecanoate 13-acetate, which have no tumor-promoting activity or ability to activate protein kinase C, did not have any effect on TAT induction by glucocorticoid. TPA enhanced the induction of TAT by various glucocorticoids but had no effect on induction of TAT by glucagon or insulin and did not enhance the induction of glucose-6-phosphate dehydrogenase by 17..beta..-estradiol. These results suggest that TPA specifically enhances the induction of TAT and ornithine decarboxylase by glucocorticoids. Similar effects of TPA on TAT induction by glucocorticoid were observed in primary cultures of adult rat hepatocytes. Another activator of protein kinase C, rac-1,2-dioctanoylglycerol, was also found to have similar effects on the cells.

• Research Organization: Univ. of Tokushima, Japan
• OSTI ID: 5596219
• Journal Information: Biochemistry; (United States), Vol. 26:8
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
59 BASIC BIOLOGICAL SCIENCES
GLUCOCORTICOIDS
BIOLOGICAL EFFECTS
PHORBOL ESTERS
AMINOTRANSFERASES
CARBON 14 COMPOUNDS
DECARBOXYLASES
DEXAMETHASONE
DOSE-RESPONSE RELATIONSHIPS
ENZYME ACTIVITY
ENZYME INDUCTION
RATS
TUMOR PROMOTERS
ADRENAL HORMONES
ANIMALS
CARBON-CARBON LYASES
CARBOXY-LYASES
CARCINOGENS
CORTICOSTEROIDS
ENZYMES
ESTERS
GENE REGULATION
HORMONES
HYDROXY COMPOUNDS
KETONES
LABELLED COMPOUNDS
LYASES
MAMMALS
NITROGEN TRANSFERASES
ORGANIC COMPOUNDS
PREGNANES
PROMOTERS
RODENTS
STEROID HORMONES
STEROIDS
TRANSFERASES
VERTEBRATES
550603* - Medicine- External Radiation in Therapy- (1980-)
550201 - Biochemistry- Tracer Techniques