Genetic differences in hypothalamic-pituitary-adrenal axis activity and food restriction-induced hyperactivity in three inbred strains of rats.

摘要: We used three inbred rat strains known for significant differences in the activity and reactivity of their hypothalamic-pituitary-adrenal (HPA) axis to stress [Fischer 344 (F344), Brown Norway (BN) Lewis (Lew) rats] search a strain difference paradoxical increase running induced by food restriction explore role HPA this behaviour. Rats were randomly assigned either an ad lib sedentary group (AL), control wheel (ACT), restriction-induced hyperactivity (FR-ACT) (1.5 h/day food, 22.5 access) or pair-fed (FR). The BN Lew rats reached 25% body weight-loss criterion FR-ACT (strain effect: F(2,132) = 45.58, P < 10-6) faster than F344 due higher F(2,65) 17.43, 0.00001). FR decreased thymus weight (marker integrated activation) all strains. In strains, further decrement on compared group. Prefeeding corticosterone levels (15.00 h) increased during study rats, but not F344. Total turns correlated both final adipose (r -0.49, 0.002) 0.59, 0.0001), emphasizing relationship between fat mass activation excessive activity. Increased conditions may be linked at level central nervous system. However, involvement corticotrophin-releasing hormone, agouti-related peptide cocaine- amphetamine-regulated transcript behavioural disturbances was excluded (in situ hybridization). propose that link initial low and/or rate loss (peripheral energy stores) activity, favouring fueling through lipolysis proteolysis reinforcing self starvation via reward mechanisms, thus establishing deleterious vicious cycle.