Effect of Estrogen on Adipose Tissue Accumulation in Chicks, with Reference to Changes in Triglyceride Synthesis and Fatty acid Oxidation

Abstract

Triglyceride synthesis and fatty acid oxidation in chick adipose tissue were studied by measuring the incorporation of [1-14C] acetate or [1-14C] palmitate into triglyceride and CO2 in vivo and in vitro in order to investigate the effect of estrogen on adipose tissue accumulation in chicks. Estrogen treatment increased the incorporation of 14C-acetate into total fatty acid and of 14C -palmitate into triglyceride . This result suggests that de novo triglyceride synthesis is stimulated by estrogen. Incorporation of 14C-palmitate into CO2 was increased by estrogen treatment, whereas that of 14C-acetate into CO2 was decreased. This result suggests that fatty acid oxidation is also stimulated by Jpn. J. Zootech. Sci., 51 (9): [673][674][675][676][677][678][679] 1980

Enzyme Activities Related to Lipid Metabolism in the Liver and Adipose Tissue of Tsaiya Ducks under Fasting and Ad libitum Feeding Conditions

“…When birds are laying, the ovarian follicles secrete estrogen to stimulate liver lipogenesis and to depress the rate of fatty acid β-oxidation. This event obviously enhances plasma TG (Hasegawa et al, 1980b;Leclercq, 1984). This study demonstrated that the activities of liver lipogenesis enzymes of ducks are higher during the laying period than during the growing period.…”

Effects of Estrogen on Triglyceride Metabolism in Chick Liver

“…Major factors contributing to the increase in serum triglyceride level may be as follows; (a) enhanced synthesis of triglyceride in the liver, (b) diminished oxidation of fatty acid in the liver, (c) enhanced secretion of triglyceride from the liver into the blood, (d) impaired removal of serum triglyceride by adipose tissue or muscle and (e) the combination of (a), (b), (c) and (d). Since estrogen significantly increased the triglyceride content in adipose tissue and muscle3, 6,8,9), the contribution of factor (d) to the hypertriglyceridemia could be ruled out. Hepatic output of triglyceride was increased by estrogen treatment in chicks and rats35,38) and Weinstein et al31) have reported that the increased rate of secretion of triglyceride by the liver produced by estrogen, regardless of mechanisms, is probably the result of a net increase in the rate of biosynthesis of triglyceride.…”