Jaundiced Gunn rats, treated with phenobarbital (60 mg per kg i.p. for 7 to 10 days) showed 25 and 36% decreases in mean plasma bilirubin levels in two experiments (p < 0.01). Kinetic studies with tracer 14C-bilirubin revealed that there was no change in bilirubin turnover or total pool size due to
Effect of combined treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin and phototherapy on bilirubin metabolism in the jaundiced gunn rat
β Scribed by Arnold N. Cohen; Jaime Kapitulnik; J. Donald Ostrow; Cecile C. Webster
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 576 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0270-9139
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β¦ Synopsis
Tetrachlorodibenzo-p-dioxin, a potent inducer of microsomal cytochrome P448-dependent monoxygenases, and phototherapy both accelerate bilirubin metabolism and decrease jaundice in Gunn rats. The effects of combined treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin and light were studied in these rats by applying phototherapy for 65 hr, beginning 5 days after induction with 2,3,7,8-tetrachlorodibenzo-p-dioxin.
2,3,7,8-Tetrachlorodibenzo-p-dioxin pretreatment caused a 75% decline in plasma bilirubin in 5 days, with no change thereafter, whether or not the rats were exposed subsequently to phototherapy. In the uninduced rats, plasma bilirubin levels declined by 55% after 40 hr of phototherapy. As determined by [ 14C]bilirubin kinetics, both 2,3,7,8-tetrachlorodibenzo-p-dioxin and phototherapy increased fractional bilirubin turnover and decreased the total bilirubin pool. In the 2,3,7,8tetrachlorodibenzo-p-dioxin-induced rats, the contracted bilirubin pool shifted from skin to liver, but these tissue pools did not change further during phototherapy. By contrast, in uninduced rats, phototherapy decreased the cutaneous bilirubin pool, which is the main target of phototherapy. 2,3,7&Tetrachlorodibenzo-p-dioxin was more effective than phototherapy in diminishing plasma bilirubin levels and the total bilirubin pool, but the combined treatment (2,3,7,8-tetrachlorodibenzo-p-dioxin followed by phototherapy) was no more effective than 2,3,7,8-tetrachlorodibenzo-pdioxin alone.
Phototherapy with intense visible light (1-4), as well as induction of microsomal cytochrome P448-dependent monoxygenases (P448) with 2,3,7,8-tetrachlorodibenzo-~ ~
π SIMILAR VOLUMES
The distribution of iron, copper, zinc, and magnesium in hepatic subcellular fractions of male and female rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was determined. Animals received 40 micrograms TCDD per kilogram per day for three days by mouth (po) or the vehicle and were killed
## Abstract An acutely toxic dose of 2,3,7,8βtetrachlorodibenzoβ__p__βdioxin (TCDD) leads to a drastically and permanently reduced feed intake and wasting by an unknown mechanism. We focused on the possible interference of TCDD with hypothalamic factors known to take part in the regulation of eatin