Hypothalamic-pituitary adrenal (HPAA) axis function in adult Fischer-344 rats exposed during development to neurotoxic chemicals perinatally.
The major objective of these experiments was to determine long-term effects on the hypothalamic-pituitary adrenal axis (HPAA) of adult rats exposed during development to chlordecone, an organochlorine insecticide. Chlordecone was administered to mothers prenatally plus the first 12 days of the neonatal period (6 ppm in the diet) or neonatally via a single subcutaneous injection to rats at 4 days of age (1 mg/pup in 20 micrograms of DMSO). DMSO (20 microliters/pup) and dexamethasone (100 micrograms/pup in 20 microliters saline) were also injected on day 4. HPAA function was evaluated at 70-80 days of age. Responsiveness of the HPAA to a repeated stressor was evaluated by exposing rats of each treatment group to a 7-day stress-induced analgesia (SIA) paradigm consisting of a daily 15 sec foot-shock (0.9 mA) exposure which was preceded by a 15 sec white noise conditioned stimulus. The behavioral response to daily stress was evaluated by measuring tail-flick latencies immediately before and/or after each stress exposure. The conditioned response to stress was evaluated 24 hours after the last of 7 daily foot-shock sessions in which rats of each treatment and experimental group were exposed to the shock chamber only. All rats were killed 15 minutes after the final session and tissue (serum and adrenals) were removed and frozen for later chemical analysis; serum and adrenal corticosterone (CS) and serum prolactin (Prl) levels were measured. Perinatal exposure to chlordecone did not significantly alter the behavioral and/or neuroendocrine responses to stress. Ambient hormone levels (both CS and Prl), however, were uniformly attenuated by chlordecone.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D007631:Chlordecone / Q000633:toxicity*; D004597:Electroshock; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000503:physiopathology; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009498:Neurotoxins / Q000633:toxicity*; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000503:physiopathology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D011916:Rats, Inbred F344; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D013045:Species Specificity; D013315:Stress, Psychological / Q000187:drug effects / Q000503:physiopathology
D007306:Insecticides; D009498:Neurotoxins; D007631:Chlordecone