Effect of Thyroxine on Fatty Acid Synthesisin Vitro

Effect of Thyroxine on Δ6 and Δ9 Desaturation Activity

“…Under these conditions it was found that treatment of the rats with thyroxine greatly stimulated the desaturation of stearic acid to oleic acid. Faas et al (1972) provide additional data in this respect adding thyroxine to subcellular fractions of rat liver, and studying de novo synthesis of fatty acids. Regarding the proportion of saturated fatty acids formed in the presence of thyroxine, these authors indicate that the hormone stimulates the microsomal desaturation reactions but has no effect on the chain elongation reactions.…”

Effects of Hypo- and Hyper-Thyroidism on In Vivo Lipogenesis in Fed and Fasted Rats

“…Increased oxidation of cholesterol and fatty acids had been documented in thyrotoxic states (Dayton 1960;Kritchevsky 1962;Myant 1968;Spirtes 1(53). However, the role of thyroid hormones in the regulation of lipogenesis has still to be established, as recently suggested by Faas, Carter andWynn (1972, 1977 In the present study, the "in vivo" Iipogenesis was studied in both Iiver and adipose tissue in thyroidectomized rats, treated with exogenous thyroxine during a prolonged period of time in order to obtain different thyroid status. These experiments were carried out in both fed, 3 and 24h fasted rats, to determine the sensitivity of the antilipogenetic effect of food deprivation.…”

Adenine nucleotide translocation in liver mitochondria of hypothyroid rats

“…Such treatment is known to restore within 2 days several rates of synthesis that are depressed in hypothyroid liver cells: RNA and protein synthesis (24), and the synthesis of the phospholipids of the membranes of microsomes, mitochondria, and nuclei (25). The desaturation of essential polyenoic fatty acids (34,44) is also accelerated by thyroid hormone in uitro. Each of these systems seems a possible target for hormone action to explain our observations.…”