Preweaning treatment with methamphetamine induces increases in both corticosterone and ACTH in rats

Treatment with methamphetamine (MA) on postnatal days P11-20 induces adult spatial learning and memory deficits without affecting monoamine levels in various brain regions. In this study, we examined the pituitary and adrenal response of animals administered MA four times daily on P11, P11-15, or fr om P11-20. Corticosterone (CORT) and adrenocorticotropin hormone (ACTH) lev els were assessed over a 1-hour period following MA exposure. On P11, MA pr oduced marked elevations of both CORT and ACTH; this is during the stress h yporesponsive period (SHRP). On P15 and P20, the maximal effect of MA on CO RT titers was observed at 30 min, with lower, but still significantly incre ased, levels at 60 min compared to controls. Males receiving MA on P15 had higher levels of ACTH than did control males, while no differences were not ed among females. On P20, MA treatment resulted in higher levels of ACTH re lative to vehicle-injected controls, but levels were not different from con trols that were only weighed at each drug administration. MA treatment inhi bited body, but not brain weight gain, resulting in hippocampal weights tha t were heavier in the MA-treated animals when expressed as a percent of bod y weight. The elevations of adrenal steroids by MA, during late phases of h ippocampal neurogenesis, may contribute to neuronal alterations that are la ter manifested in deficits of learning and memory. (C) 2000 Elsevier Scienc e Inc. All rights reserved.