Type 2 diabetes is related to oxidative stress. The incidence of type 2 diabetes is higher in men than in pre-menopausal women. The role of estrogens on the protection against oxidative stress has been demonstrated.

Aim: 

To evaluate oxidative stress differences between male and female diabetic rats and its importance to the development of the disease.

Methods: 

We used male and female Goto-Kakizaki (GK) rats. They exhibit similar metabolic, hormonal and vascular disorders to the human diabetes disease and are non-obese.

Results: 

The rate of the progression of diabetes was higher in male than in female rats. Males reached a hyperglycaemia of 200 mg/dL at around 20 weeks old and females at 36 weeks old. When the animals reached this concentration, we determined in vivo glucose consumption, sacrificed them and measured oxidative stress parameters. We found that hepatic isolated mitochondria from males produce 40% more hydrogen peroxide, show a 50% higher ratio of GSSG/GSH and 200% higher MDA levels that those from females. Moreover, xanthine oxidase activity in plasma was significantly higher in males than in females. Brain and heart glucose consumption determined by positron emission tomography was lower in males than in females, thus demonstrating a lower capacity of male rats to uptake glucose into the cells.

In conclusion, we find significant gender differences in oxidative stress parameters as well as those related to glucose consumption in diabetic rats, which could explain, at least in part, the lower incidence of type 2 diabetes in pre-menopausal women compared to men.

This work has been supported by BFU2007-65803/BFI and ISCIII2006-RED13-027 from the 'Red Temática de investigación cooperativa en envejecimiento y fragilidad' (RETICEF RD06/003–027) to J.V., by grant GV/2007/263 to C.B and by grants GVPRE/2008/138 and Catholic University 2008-011-002 to J. G.