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The role of estradiol-17 beta in the regulation of ovine adipose tissue lipid metabolism and feed intake
Abstract
The effect of estradiol 17$\beta$ (E$\sb2$) on adipose tissue metabolism and feed intake was studied in five trials. In trial 1, the relationship of feed intake and E$\sb2$ in plasma were characterized in twin-bearing ewes (n = 10) during late gestation and during lactation. Feed intake decreased 1.8-fold from 60 d prepartum to parturition as E$\sb2$ in plasma increased 3-fold. Feed intake increased 2.8-fold during the first 30 d of lactation when E$\sb2$ in plasma was 13-fold lower than the last week of gestation. In trial 2, feed intake was determined (30 d) in ovariectomized ewes implanted with (n = 9) E$\sb2$ to attain concentrations of E$\sb2$ indicative of late gestation or a sham implant (n = 9). Intake decreased transiently in ewes implanted with E$\sb2$. Trials 1 and 2 indicated E$\sb2$ was a potential feed intake regulator during late gestation. In trial 3, subcutaneous adipose tissue was biopsied from thirteen twin-bearing ewes to characterize lipid metabolism during $-$30, $-$15, 0, 15 and 30 d relative to parturition. De novo lipogenesis and palmitate esterification decreased as non-esterified fatty acid and glycerol release (lipolysis) increased during late gestation. During lactation lipogenesis and esterification increased while lipolysis decreased. In trial 4, the interaction of body condition and E$\sb2$ on lipid metabolism was evaluated in lean (68 kg) and obese (87 kg) ovariectomized ewes receiving implants containing E$\sb2$ or sham implants. Biopsies of subcutaneous adipose tissue were taken at 0, 5 and 30 d post-implantation to determine lipogenesis, esterification and lipolysis. Lipogenesis was inhibited in ewes implanted with E$\sb2$ as compared to ewes without E$\sb2$. Lean ewes without E$\sb2$ had higher rates of lipogenesis over time than obese ewes without E$\sb2$. Esterification increased in lean but decreased in obese ewes without E$\sb2$. Slices of adipose tissues were cultured (48 h) to evaluate the effect of E$\sb2$ on lipid metabolism. Lipogenesis and esterification were decreased by E$\sb2$ in the culture. Lipolysis in trials 4 and 5 had little or highly variable responses to E$\sb2$. These data indicated increased concentrations of E$\sb2$ in plasma during late gestation may directly effect energy metabolism via decreasing feed intake and independently decreasing de novo lipogenesis and palmitate esterification.
Subject Area
Livestock
Recommended Citation
Green, David Alan, "The role of estradiol-17 beta in the regulation of ovine adipose tissue lipid metabolism and feed intake" (1991). ETD collection for University of Nebraska-Lincoln. AAI9133292.
https://digitalcommons.unl.edu/dissertations/AAI9133292