Table 1.
Role and mechanism of action of T3 on activity or expression of enzymes and other proteins involved in fatty acid metabolism.
| Experimental Model | Time of Treatment | Effect of T3 on Lipid Metabolism | Mechanism of Action | Ref. | |
|---|---|---|---|---|---|
| In vitro studies | |||||
| HepG2 cells | 24 h | ↑ | FAS mRNA | Genomic | [28] |
| HepG2 cells | Up to 24 h | ↑ | SREBP-1 protein synthesis | Non genomic | [30] |
| Hepatocytes from eu- and hypothyroid rats fed chow diet | 4 h | ↑ | Synthesis of fatty acids and their incorporation into lipid fractions | Not reported | [62] |
| Cultured hepatocytes from chick embryo | Up to 49 h | ↑ | ACC promoter activity and mRNA abundance | Genomic | [66,67] |
| Cultured hepatocytes from chick embryo | Up to 48 h | ↑ | ME, FAS, ACC enzyme activity and mRNA abundance | Genomic | [76,71] |
| Hepatocytes from hypothyroid rats | 24 h | ↑ | ACLY protein level and activity | Not reported | [82] |
| HepG2 cells | 24 h | ↑ | ME promoter activity | Genomic | [83] |
| In vivo studies | |||||
| Liver from eu- and hyperthyroid rats fed chow diet. | 4 weeks | ↑ | SREBP-1 protein level | Not reported | [30] |
| Liver from eu- and hypothyroid rats fed chow diet | 4 weeks | ↑ | Mitochondrial citrate carrier expression, nuclear transcription rate and splicing efficiency | Genomic | [53,54] |
| Liver from eu- and hyperthyroid rats fed fat-enriched chow diet. | 7 days | ↑ | Fatty acid synthesis | Not reported | [63] |
| Liver from hypo- and hyperthyroid rats fed chow diet. | 7 days | ↑ | ACC mRNA abundance | Not reported | [69] |
| Liver from eu-, hypo- and hyperthyroid mice fed chow diet. | 5 days | ↓ | SREBP-1 mRNA abundance and SREBP-1 promoter activity | Genomic | [74] |
| Liver from eu-, hypo- and hyperthyroid mice fed chow diet. | 5 days | ↑ | ChREBP mRNA abundance and protein level; ChREBP promoter activity | Genomic | [77] |
| Liver from eu- and hyperthyroid mice fed chow diet or high carbohydrate diet. | Not reported | ↑ | ChREBP mRNA abundance; ChREBP promoter activity | Genomic | [78] |
| Liver from eu-, hypo-, and hyperthyroid rats, starved and refed on carbohydrate-rich diet | 7 days | ↑ | G6PD enzyme activity | Non genomic | [85] |
| Liver from eu- and hyperthyroid rats fed chow diet or high carbohydrate, fat-free diet. | 7 days | ↑ | ME mRNA abundance and enzyme activity | Not reported | [92] |
| Liver from eu- and hyperthyroid rats fed chow diet or high carbohydrate, fat-free diet. | 7 days | ↑ | ME, G6PD and 6PGD enzyme activity, mRNA abundance and relative rate of enzyme synthesis | Genomic and non-genomic | [95] |
| Liver from hypo- and hyperthyroid rats fed chow diet | Up to 4 h | ↑ | Spot 14 protein (S14) mRNA abundance | Not reported | [96] |
| Liver from eu- and hyperthyroid rats fed chow diet | 1 day | ↑ | Induction of citrate carrier activity | Not reported | [80] |
↓ Decrease; ↑ Increase.