INFLUENCE OF GENDER AND TIMING OF INITIATION OF TREATMENT ON LICL ENHANCEMENT OF NZB W SURVIVAL/

Daily administration of 4 mg (LiCl)-Li-6 to groups of male NZB/W mice starting at 8 weeks of age did not lead to enhancement of long-term su rvival. These results are in contrast to previous studies where simila r treatment of female NZB/W mice was very effective at enhancing long- term survivors. The finding that survival of male NZB/W mice was not i nfluenced by Li is consistent with previous observations that Li treat ment was not effective in male MRL-lpr and BxSB mice and thus gender-d ependent factors are implicated in lithium's action. Initiation of Li treatment of female NZB/W at 4 weeks of age, prior to sexual maturity, was also found to be less effective at enhancing long-term survival t han starting treatment after sexual maturity (7 to 8 weeks) but before onset of disease (16 to 28 weeks). The finding that Li treatment is m ore effective when initiated in sexually mature female NZB/W mice also support the conclusion that gender-dependent factors influence the ef fectiveness of Li action in this model of systemic lupus erythematosus .