In vivo Effects of T-2 Mycotoxin on Protein and DNA Synthesis in Rat Tissues

摘要

Rats were given an ip injection of T-2 mycotoxin (T-2); the T-2 metabolite, T-2tetraol (tetraol); or cycloheximide. Serum, liver, heart, kidney, spleen, muscle, and intestine were collected at 3, 6 and 9 hr post injection after a 2-hr pulse at each time with (14)C-leucine and (3)H-thymidine. Protein and DNA synthesis levels in rats were determined by dual-label counting of the acid-precipitable fraction of tissue homogenates. With a lethal dose of T-2, tetraol, or cycloheximide, maximum levels of protein synthesis inhibition were observed in all the tissues at the earliest time period and continued for the duration of the study (9 hr). Additional rates given the same dose of any of the three treatments died between 14 and 20 hr. With sub-lethal doses of T-2 or tetraol, the same early decrease in protein synthesis was observed, but recovery in most of the tissues was seen with time. DNA synthesis in the T-2 treated rats was also suppressed, although to a lesser degree, in the six tissues studied. With sub-lethal doses, complete recovery of DNA synthesis took place in four of the six tissues by 9 hr after toxin exposure. An increase in tissue-pool levels of free leucine and thymidine in response to T-2 mycotoxin was also noted. T-2 mycotoxin caused a very rapid inhibition of protein and DNA synthesis in all of the tissues studied. Its effects in whole animals were the same as those of the T-2 metabolite, tetraol, and a known protein synthesis inhibitor, cycloheximide. Keywords: Protein synthesis; DNA Synthesis. (KT)