Radioprotection by 16, 16 dimethyl prostaglandin E2 is equally effective in male and female mice

Pretreatment with 16, 16 dimethyl prostaglandin E2 (DiPGE2) provides effective protection against radiation and chemical injury. Cytoprotection against chemical injury is known to be influenced by sex factors, and is more effective in females than males. Since prostaglandin metabolism and biological responses to prostaglandin may vary between sexes, studies were conducted to compare DiPGE2-induced radioprotection in male and female mice. Pretreatment with 400 μg DiPGE2/kg body wt substantially enhanced 30-day survival in males and females. There was no significant difference in the LD50/30 of male and female mice receiving vehicle alone prior to irradiation, 8.34 Gy versus 8.46 Gy, respectively. DiPGE2 treatment increased the LD50/30 in males to 12.1 Gy, providing a dose modification factor (DMF) of 1.45. Similar increases were observed in females, with a LD50/30 of 11.6 and a DMF of 1.37. The reported difference in DiPGE2-induced cytoprotection between males and females exposed to ethanol injury, and the lack of variation in the present radioprotection study suggests that separate mechanisms are involved in the two processes. (author)