Induction of spermidine/spermine N1-acetyltransferase in needle-punctured rat lens as a model of traumatic cataract.
Isolated rat lens was punctured with a needle at a single point in the equatorial region and was incubated at 37 degrees C. Spermidine/spermine N1-acetyltransferase activity was increased about 5-fold at 8 h after the puncture. Concomitantly, putrescine content in the lens increased markedly at 8-16 h after the puncture, while spermidine levels were slightly depressed. Pretreatment of the lens with actinomycin D or cycloheximide blocked the increases of spermidine/spermine N1-acetyltransferase activity and putrescine content. Ornithine decarboxylase, on the other hand, was not induced to a detectable degree by this stimulus and 5 mM difluoromethylornithine could not block the increase of putrescine content. Polyamine oxidase showed a relatively constant activity that was sufficient for the metabolism of newly formed N1-acetylspermidine. These results suggested that, in the punctured lens, the polyamine levels were regulated predominantly by the activity of spermidine/spermine N1-acetyltransferase, but not by the induction of ornithine decarboxylase.
D000123:Acetyltransferases / Q000096:biosynthesis*; D000818:Animals; D002386:Cataract / Q000201:enzymology* / Q000209:etiology; D004790:Enzyme Induction; D005131:Eye Injuries / Q000150:complications / Q000201:enzymology*; D007908:Lens, Crystalline / Q000201:enzymology*; D008297:Male; D009955:Ornithine Decarboxylase / Q000378:metabolism; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014950:Wounds, Penetrating / Q000201:enzymology; D000097667:Polyamine Oxidase; D000099228:Diamine N-Acetyltransferase
D000123:Acetyltransferases; D009955:Ornithine Decarboxylase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D011073:Polyamines; D000097667:Polyamine Oxidase; D000099228:Diamine N-Acetyltransferase