Testosterone Increases Lipolysis and the Number of β-Adrenoceptors in Male Rat Adipocytes*

Abstract

The influence of androgen status on the regulation of lipolysis and number of beta-adrenoceptors in isolated adipocytes was studied in male rats. Castration resulted in decreased catecholamine-induced as well as forskolin-induced lipolysis. beta-adrenoceptor number, examined by a whole cell cyanopindolol binding assay, was also diminished to a similar extent. Testosterone treatment of castrated rats normalized lipolysis as well as beta-adrenoceptor number. These results demonstrate that testosterone stimulates catecholamine-induced lipolysis in vivo by increasing the number of beta-adrenoceptors as well as the activity of adenylate cyclase, confirming previous in vitro studies performed in adipose precursor cells.

Expression and activity of steroid aldoketoreductases 1C in omental adipose tissue are positive correlates of adiposity in women

“…Androgens have been shown to exert a lipolytic action in adipocytes from rats (36). Accordingly, fatty acid turnover was increased in men treated with testosterone (21,22).…”

The effect of obesity on the ratio of type 3 17β-hydroxysteroid dehydrogenase mRNA to cytochrome P450 aromatase mRNA in subcutaneous abdominal and intra-abdominal adipose tissue of women

“…32 Testosterone may mediate this effect because it has been shown to increase adipocyte badrenergic receptor expression. 33,34 Increased delivery of free fatty acids to the liver has been implicated in the reduced insulin clearance and dyslipidaemia associated with central obesity. 35 In summary, these studies have suggested that adipose tissue from the subcutaneous abdominal and intra-abdominal sites of women has different steroidogenic potentials which may be influenced by body weight.…”

Free testosterone plasma levels are negatively associated with the intima-media thickness of the common carotid artery in overweight and obese glucose-tolerant young adult men

“…2 On the other hand, low testosterone levels are responsible for higher body fat; in fact, testosterone, acting through a specific receptor, 3 has lipolytic effects in adipocytes; 4,5 moreover, in vivo studies performed in men have shown that testosterone supplementation causes a more rapid turnover of triglycerides in the subcutaneous abdominal adipose tissue region 6 and inhibits lipoprotein-lipase (LPL) activity and triglyceride uptake and assimilation, 6,7 these effects being prominent in the intraabdominal fat depot. 7 An inverse association has been found between plasma testosterone levels and the extent of coronary artery disease (CAD) in men with angina pectoris, thus suggesting that low testosterone levels may be a risk factor for CAD.…”