Hypothalamo-pituitary-adrenocortical axis in stress-susceptible and stress-resistant pigs: endocrine responses to corticotrophin-releasing factor and vasopressin*

摘要: Summary Swiss Landrace pigs selected into genetically well-characterized low and high tissue fat lines (f F respectively) react differently to exogenous endogenous stressors. Response of the hypothalamo-pituitary-adrenocortical (HPA) axis i.v. administered ovine corticotrophin-releasing factor (oCRF) lysine vasopressin (LVP) in young females, intact pretreated with dexamethasone or metyrapone, leads conclusion that different stress susceptibility two correlates sensitivity pituitary corticotrophs oCRF stimulation. Total amount ACTH released after stimulation submaximal doses was roughly equal both lines, cortisol level is even lower f-line, most likely due considerably enhanced metabolic clearance rate (lower half-life plasma compared F-line). LVP-stimulated release comparable stronger f-line. Combined effect LVP rather additive than synergistic but ratio cortisol/ACTH this about four times higher for by separately. In cases externally stimulated HPA axis, concentration tightly cross-correlates ACTH.