RT Journal Article
SR Electronic
T1 Studies on Triiodothyronine-Induced Synthesis of Liver Mitochondrial α-Glycerophosphate Dehydrogenase in the Thyroidectomized Rat
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 44
OP 51
VO 3
IS 1
A1 KAI-LIN LEE
A1 O. NEAL MILLER
YR 1967
UL http://molpharm.aspetjournals.org/content/3/1/44.abstract
AB Administration of a single small dose of triiodothymonine (T3) greatly increased liver mitochondrial L-α-glycerophosphate dehydrogenase activity of thyroidectomized rats. The induction of liver mitochondrial L-α-glycerophoshate dehydrogenase by T3 could be blocked by simultaneous administration of puromycin; in addition, time incorporation of L-leucine-14C into total liver proteins and into proteins of all subcellular fractions was greatly inhibited. Furthermore, puromycin blocked further induction when it was administered after the administration of T3. L-Ethionine prevented the induction of enzyme formation, and the inhibition could be partially reversed by L-methionine. "Pulse labeling" was used to study the incorporation of L-leucine-14C into liver proteins, and the data indicate that an increased rate of protein synthesis precedes the maximal increase in liver mitochondrial L-α-glycerophosphate dehydrogenase produced by T3-administration. These observations suggest that T3-induction of L-α-glycerophosphate dehydrogenase in the thyroidectomized rat results from acceleration of enzyme synthesis. Similar observations were reported earlier with the euthyroid rat. Administration of actinomycin D along with the T3 abolished the increase of L-α-glycerophosphate dehydrogenase in liver mitochondria. The induction was also partially inhibited by 5-fluorouracil. These results indicate that the induction process depends on the formation of an adequate amount of renewable messenger-RNA molecules. ACKNOWLEDGMENTS This work was supported by a grant from the United States Public Health Service, TIGM-648-05. Time experimental data are taken from a dissertation submitted by Kai-Lin Lee to the Graduate School of Tulane University in partial fulfillment of the requirements for the degree of Doctor of Philosophy, 1966.