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Insulin regulates enzyme activity, malonyl-CoA sensitivity and mRNA abundance of hepatic carnitine palmitoyltransferase-I.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Park, Edwards Amasa Mynatt, Randall L. Cook, Gregory A. Kashfi, Khosrow |
| Copyright Year | 1995 |
| Abstract | The regulation of hepatic mitochondrial carnitine palmitoyltransferase-I (CPT-I) was studied in rats during starvation and insulin-dependent diabetes and in rat H4IIE cells. The Vmax. for CPT-I in hepatic mitochondrial outer membranes isolated from starved and diabetic rats increased 2- and 3-fold respectively over fed control values with no change in Km values for substrates. Regulation of malonyl-CoA sensitivity of CPT-I in isolated mitochondrial outer membranes was indicated by an 8-fold increase in Ki during starvation and by a 50-fold increase in Ki in the diabetic state. Peroxisomal and microsomal CPT also had decreased sensitivity to inhibition by malonyl-CoA during starvation. CPT-I mRNA abundance was 7.5 times greater in livers of 48-h-starved rats and 14.6 times greater in livers of insulin-dependent diabetic rats compared with livers of fed rats. In H4IIE cells, insulin increased CPT-I sensitivity to inhibition by malonyl-CoA in 4 h, and sensitivity continued to increase up to 24 h after insulin addition. CPT-I mRNA levels in H4IIE cells were decreased by insulin after 4 h and continued to decrease so that at 24 h there was a 10-fold difference. The half-life of CPT-I mRNA was 4 h in the presence of actinomycin D or with actinomycin D plus insulin. These results suggest that insulin regulates CPT-I by inhibiting transcription of the CPT-I gene. |
| File Format | PDF HTM / HTML |
| DOI | 10.1042/bj3100853 |
| Alternate Webpage(s) | http://www.biochemj.org/content/ppbiochemj/310/3/853.full.pdf |
| PubMed reference number | 7575418 |
| Alternate Webpage(s) | https://doi.org/10.1042/bj3100853 |
| Journal | Medline |
| Volume Number | 310 |
| Part | 3 |
| Journal | The Biochemical journal |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
