Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.1.17 (ornithine decarboxylase)
 6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Topical application of benzo[a]pyrene (B[a]P) at dose rates of 32 or 64 micrograms/week to the dorsal skin of female Swiss (ICR) mice resulted in a marked and rapid increase in concentration of RNA for transforming growth factor beta 1 (TGF-beta 1) in epidermis. Two RNA species 1.9 and 2.5 kb, detected by a mouse TGF-beta 1 cDNA probe, were coordinately expressed. The concentration of these species appeared to be maximal 6-12 h after application, and returned to control levels after 48 h. A second, less intense maximum was observed 72-96 h after treatment. Similar effects were observed in CD-1 and HRS (both hr/hr and hr/+) mice, which are also sensitive to B[a[] tumorigenesis. In comparison with 32 and 64 micrograms/week a dose rate of 16 micrograms/week was essentially without activity in increasing TGF-beta 1 RNA concentration. All three dose rates induced an increase in epidermal RNA for ornithine decarboxylase, however, and with kinetics similar to those observed with the potent tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate. The results obtained support other findings made in this laboratory, that at high dose rates above 16 micrograms tumorigenesis by B[a]P involves a strong tumor-promoting component. The latter further appears to be mediated by increased TGF-beta 1 expression.
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PMID:Stimulation of TGF-beta 1 mRNA concentration in mouse skin treated with benzo[a]pyrene. 173 76

The effects of acute, multiple, and chronic exposure of hairless mice to ultraviolet radiation (UVR) on induction of epidermal ornithine decarboxylase (ODC) (EC 4.1.1.17) activity were investigated. Acute UVR exposure results in a biphasic time course of induction of epidermal ODC activity. Enzyme activity maxima occur at 3 and 24 h postirradiation. The biphasic time course is observed in two different strains of hairless mice (Skh:HR-1 and Jackson HRS/J) when the UVR source is either UBV fluorescent tubes or a solar simulator. The ratio of 24-h/3-h postirradiation ODC activity increases with increasing UVR dose. UVR induction of ODC activity was not significant below the mouse minimum erythemal dose (MED). The 3- and 24-h ODC activities have similar apparent Kms for ornithine (34 and 50 microM, respectively), and thermal stabilities at 52 degrees C (t1/2 = 23 and 18 min, respectively), and exhibit similar half-lives in vivo (t1/2 = 15 and 18 min, respectively). Multiple UVR exposure experiments showed 24-h ODC activity is sensitive to the preexposure history of the mouse, while 3-h ODC is not. Preexposure of hairless mice to several sub-MED levels of simulated solar radiation (SSR) specifically suppresses induction of 24-h ODC by a follow-up 2 x MED of SSR. Preexposure to a single 2 x MED of SSR specifically enhances induction of 24-h ODC induced by a second 2 x MED of SSR administered 48 h after the first. The 3-h ODC was not significantly affected by either preexposure regimen. Preexposure to a single high or low dose of UVA radiation did not affect epidermal ODC activity nor had an effect on ODC induction by UVB radiation. Several weeks of chronic exposure to UVB radiation elevated basal levels of epidermal ODC substantially (up to 350-fold). In these chronically irradiated mice, exposure to 2 x MED SSR resulted in a further 3.5-fold increase in ODC activity over the elevated basal level. These data reveal novel properties of epidermal cell expression of ODC activity in response to acute and chronic UVR insult. The results provide additional insight into the use of ODC as a marker for skin photodamage.
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PMID:Acute and chronic ultraviolet radiation induction of epidermal ornithine decarboxylase activity in hairless mice. 230 17

The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on skin of congenic haired and hairless newborn and adult HRS/J mice was studied. In all adult animals topical application of TCDD caused an involution of sebaceous glands. Epidermal/epithelial hyperplasia and hyperkeratinization was induced in the hairless, but not the haired mice. Trans-glutaminase (TG) activity was stimulated in both haired and hairless animals. A single application of 1 microgram of TCDD did not stimulate significant ornithine decarboxylase activity in the skin in either strain. Other than a reduction in the density of the inflammatory cell infiltrate in the dermis, topical treatment with antiinflammatory agents fluocinolone acetonide and indomethacin did not affect the cutaneous response to TCDD. Skin of newborn mice treated topically with TCDD over a 2-wk period reacted much the same as adult skin in that sebaceous glands were reduced in size and TG activity was stimulated in both haired and hairless neonates; but epidermal hyperplasia occurred only in the hairless, not the haired newborns.
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PMID:Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on murine skin. 289 97