Regulation of cholinephosphotransferase by thyroid hormone

We have demonstrated earlier that thyroid hormone (T-3) regulates the activ ity of cholinephosphotransferase (CPT) in guinea pig lung. This effect of T -3 is not organ specific because we found T-3 also regulates CPT activity i n the guinea pig liver. Northern blot analysis using two oligonucleotide pr obes, one synthesized on the basis of the yeast CPT gene sequence and anoth er on the basis of partial cDNA clone from guinea pig CPT clone, revealed t hat T-3 stimulates the expression of new CPT mRNA, Studies with transcripti onal and translational inhibitors indicated that T-3 enhanced the translati on of the CPT mRNA as well as translocation of preformed CPT enzyme protein from cytosol to mitochondria, Furthermore, it strengthens our previous fin ding that yeast CPT and guinea pig CPT have high homology in their sequence as both the oligonucleotide probes gave the similar type of Northern blot in the present study. (C) 2001 Academic Press.