Effects of interscapular Brown adipose tissue denervation on body weight and energy metabolism in ovariectomized and estradiol-treated rats

• Published in: Behavioral neuroscience 1984-01, Vol.98 (4), p.674-685
• Main Authors: Bartness, Timothy J, Wade, George N
• Format: Article
• Language: English
• Subjects: Adipose Tissue, Brown - metabolism; Adipose Tissue, Brown - physiology; Animal; Animals; Biological and medical sciences; Body Temperature Regulation; Body Weight; Castration; Denervation; Energy Expenditure; Energy Metabolism; Estradiol; Estradiol - pharmacology; Estradiol - physiology; Female; Female Animals; Food Intake; Fundamental and applied biological sciences. Psychology; Neural Lesions; Ovariectomy; Oxygen Consumption; Rats; Sympathetic Nervous System; Sympathetic Nervous System - physiology; Thermoregulation (Body); Thermoregulation. Hibernation. Estivation. Ecophysiology and environmental effects; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0735-7044; 1939-0084
• DOI: 10.1037/0735-7044.98.4.674

Ovariectomy-induced increases and estradiol-induced decreases in body weight cannot be fully accounted for by changes in energy intake and appear to reflect alterations in thermogenesis. Because changes in energy expenditure have been linked to altered sympathetic nervous system (SNS) activity in brown adipose tissue (BAT), the role of estradiol in thermogenesis and body weight, as mediated by the SNS innervation of interscapular BAT (IBAT), was examined. In 2 experiments, with 66 Sprague-Dawley rats, the IBAT of ovariectomized Ss was bilaterally or unilaterally surgically denervated. The chow-fed, bilaterally denervated group gained more weight than the unilaterally denervated or sham-operated group, an effect that was exaggerated by sucrose feeding. Food intake did not differ among the groups within each dietary condition. Estradiol benzoate (EB; [4 |mg/day, sc]) decreased body weight in all groups. Bilateral, and to a lesser extent, unilateral IBAT denervation blocked the EB-induced increase in thermogenesis. EB increased IBAT wet weight regardless of surgical treatment. The EB-induced increase in denervated IBAT wet weight was most likely due to decreased lipolysis produced by the surgical sympathectomy. Results are discussed in terms of the role of the SNS and IBAT in the mediation of estradiol-induced changes in body weight and energy metabolism. (39 ref)