© 1994 Oxford University Press
research-article |
Erythrocyte and Plasma Cholinesterase Activity in Male and Female Rhesus Monkeys before and after Exposure to Sarin1





*United States Army Medical Research & Development Command Fort Detrick, Frederick, Maryland 21702-5012
United States Naval Medical Research Unit Cairo, Republic of Egypt. FPO AE 09835-007 United States Army Medical Research Institute of Chemical Defense Aberdeen Proving Ground, Maryland 21010-5425
Walter Reed Army Institute of Research Washington, DC 20307
Received October 12, 1993; accepted April 20, 1994
The rhesus monkey (Macaca mulatta) has a menstrual cycle similar to the human. Differences in hormone levels have been demonstrated between the sexes and in females during the menstrual cycle but these differences in terms of organophosphorus toxicity have not been explored. Plasma cholinesterase (ChE/BuChE) and erythrocyte (RBC) acetylcholinesterase (AChE) activity were measured before and after exposure to the organophosphorus compound sarin (11 µg/kg, iv; 0.75 LD50) in six male and six female rhesus monkeys. After baseline measurements were obtained, sarin was administered to atropinized monkeys to determine in vivo differences between the sexes in their response to sarin. With the baseline values, the intraanimal and intragroup BuChE/AChE variations were found to be minimal. Following sarin intoxication and 2-PAM treatment no significant differences were seen between the sexes in the rate of reactivation of BuChE or AChE by 2-PAM. The rate of aging of sarin phosphonylated RBC AChE between the sexes was also similar. De novo regeneration of RBC AChE and plasma BuChE after sarin intoxication was different between the male and female monkeys. The female plasma BuChE recovery rate was 48% slower than the male recovery rate, while the early (first 63 days) RBC AChE recovery rate was 24.5% faster in the females. In conclusion, there probably are not any clinically significant differences between male and female rhesus monkeys acutely intoxicated with sarin. However, on subsequent exposure clinical differences may be observed due to substantial differences in the rate of de novo synthesis of both plasma BuChE and RBC AChE.