Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2005
Publication Date: 5/12/2005
Citation: Lay Jr, D.C., Toscano, M.J., Kattesh, H.G., Mcmunn, K.A. 2005. Swine dams exposed to psychological stress or physical stress produce offspring with an altered physiologic response to weaning stress. 9th Multidisciplinary International Conference of Biological Psychiatry.
Technical Abstract: Exposing pregnant mammals to prenatal stress has been shown to alter the stress response of their resulting offspring. Most stressors are a combination of psychological and physical stressors; therefore, we designed the following study to separate some confounding factors. One of our objectives was to determine which physiological factors, altered by prenatal stress, are due to the dam experiencing psychological stress versus physical stress. Previous work in our laboratory has shown that male pigs at 2 months of age have greater concentrations of hypothalamic CRF and beta-endorphin if they were born to dams who had received injections of ACTH during pregnancy. In this study, sows treatments consisted of i.v. injections of adrenocorticotrophin (ACTH, 1 IU/kg BW) (n = 11), exposure to rough handling for a 10-minute duration (n = 13), or no treatment (control, n = 13) once a week during d 42 to d 77 of gestation. Injections of ACTH were used to elevate plasma glucocorticoids, without causing the psychological stress assumed to result from rough handling. We found that when pigs were subjected to the stress of weaning, those that were born to dams who were roughly handled during pregnancy had a lower (P < .05) free cortisol index (FCI, cortisol concentration divided by corticosteroid binding globulin concentration) when compared to pigs from dams who served as controls or were injected with ACTH. Furthermore, we found that pigs from control dams exhibited a FCI that continued to remain elevated (P < .05) at 6 days after weaning while pigs from ACTH treated and roughly handled dams reached a lower index. These data indicate that prenatal stress causes offspring to have less biologically available plasma cortisol in response to the chronic stress of weaning. In addition, these data indicate that the effects of prenatal stress are derived, in part, from direct activation of the hypothalamic-pituitary-adrenal axis. It is likely that severity and type of psychological stress will influence the degree to which prenatal stress effects are observed in offspring.