Effect of α2-adrenergic antagonist on some factors secreted by adipose tissue in obese male rats

Obesity is a major risk factor for type 2 diabetes, hypertension, hyperlipidemia, cardiovascular disease and certain types of cancer. Furthermore, obesity is associated with insulin resistance and hyperinsulinaemia. Hormones and cytokines such as leptin and TNF are produced by adipose tissue and have a key role in insulin resistance of obesity. The purpose of this study was to examine the effects of peripheral administration of yohimbine on some of adipose factors. Experiments were carried out on two groups of male rats: lean control group (fed standard purina rodent chow) and obese group (fed cafeteria diet). A blood sample was taken from each rat, after exposure to diet for 18 weeks. The obese group were randomly divided into two groups. Group I was injected with 4mg/kg yohimbine and group II received the equal volume of saline. Blood samples were taken 30, 60, and 120 min after drug or saline injection. Insulin level was significantly increased 30 and 60 minutes after injection (P<0.05). TNF- and leptin levels were decreased (P<0.05) while FFA level was increased in response to yohimbine, 30 minutes after injection. Glucose level was increased but it was lower than control group during 120 minutes. It has been shown previously that cAMP is the main regulatory factor of leptin, TNF- and FFA in adipocytes. In comparison to the obtained results in the control group, we conclude that probably sensitivity of – adrenergic receptors and -AR proportion are increased in obesity.