Characterizing the postnatal hypothalamic-pituitary-adrenal axis response of in utero heat stressed pigs at 10 and 15 weeks of age

Authors: MASKAL, JACOB - Purdue University; BRITO, LUIZ - Purdue University; DUTTLINGER, ALAN - Purdue University; KPODO, KOUASSI - Purdue University; MCCONN, BETTY - Purdue University; BYRD, CHRISTOPHER - Purdue University; RICHERT, BRIAN - Purdue University; Marchant, Jeremy; Lay Jr, Donald; PERRY, SHELBI - University Of Missouri; LUCY, MATTHEW - University Of Missouri; SAFRANSKI, TIM - University Of Missouri; Johnson, Jay

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2021
Publication Date: 11/18/2022
Citation: Maskal, J.M., Brito, L.F., Duttlinger, A.W., Kpodo, K.R., Mcconn, B.R., Byrd, C.J., Richert, B.T., Marchant, J.N., Lay Jr, D.C., Perry, S.D., Lucy, M.C., Safranski, T.J., Johnson, J.S. 2022. Characterizing the postnatal hypothalamic-pituitary-adrenal axis response of in utero heat stressed pigs at 10 and 15 weeks of age. Scientific Reports. 11. Article 22527. https://doi.org/10.1038/s41598-021-01889-w.
DOI: https://doi.org/10.1038/s41598-021-01889-w

Interpretive Summary: In utero heat stress alters postnatal physiological and behavioral stress responses in pigs. However, the mechanisms underlying these postnatal alterations have yet to be determined. Therefore, the study objective was to characterize the postnatal hypothalamic-pituitary-adrenal axis response in pigs exposed to in utero heat stress. Pigs derived from mothers that were exposed to heat stress or normal conditions during pregnancy were subjected to tests designed to evaluate how the hypothalamic-pituitary-adrenal axis functions at 10 and 15 weeks of age. It was determined that in utero heat stressed pigs had an altered stress hormone response to the hypothalamic-pituitary-axis challenge relative to controls. In addition, advancing age altered the stress hormone response to the hypothalamic-pituitary-adrenal axis challenge. In summary, both in utero heat stress and age alters the hypothalamic-pituitary-adrenal axis response in pigs.

Technical Abstract: In utero heat stress alters postnatal physiological and behavioral stress responses in pigs. However, the mechanisms underlying these postnatal alterations have yet to be determined. The study objective was to characterize the postnatal hypothalamic-pituitary-adrenal axis response in pigs exposed to in utero heat stress. All pigs were subjected to a dexamethasone suppression test followed by a corticotrophin releasing hormone challenge at 10 and 15 weeks of age. Following the challenge, hypothalamic, anterior pituitary, and adrenal tissues were collected from all pigs for mRNA abundance analyses. At 10 weeks of age, in utero heat stressed pigs had a reduced (P < 0.05) cortisol response to the corticotrophin releasing hormone challenge when compared to controls. In addition, the cortisol response tended to be greater (P < 0.10) in 15 versus 10-week-old pigs in response to the dexamethasone suppression test, regardless of in utero treatment. The cortisol response tended to be reduced (P < 0.10) in 15 versus 10-week-old pigs in response to the corticotrophin releasing hormone challenge, regardless of in utero treatment. Hypothalamic and anterior pituitary glucocorticoid receptor mRNA abundance was reduced (P < 0.05) in 15 versus 10-week-old pigs, regardless of in utero treatment. In summary, in utero heat stress altered some aspects of the hypothalamic-pituitary-adrenal axis related to corticotropin releasing hormone signaling, and age influenced this response.