Pubertal-related changes in hypothalamic-pituitary-adrenal axis reactivity and cytokine secretion in response to an immunological stressor.
Pubertal development is marked by profound changes in stress reactivity. For example, following a brief stressor, such as foot shock, ether inhalation or restraint, prepubertal rats display a prolonged adrenocorticotrophic hormone (ACTH) and corticosterone response that takes twice as long to return to baseline compared to adults. Pubertal-related differences in the recovery of the hormonal stress response following a more protracted systemic stressor, such as an immunological challenge, have not yet been investigated. Moreover, it is unclear whether an immunological stressor leads to a differential cytokine response in animals before and after pubertal maturation. To examine these issues, we used a single injection of lipopolysaccharide (LPS; 0.1 mg/kg) to induce a hormonal stress and innate immune response and measured plasma ACTH, corticosterone, and the pro-inflammatory cytokines interleukin (IL)-1β and IL-6 in prepubertal and adult male rats 0, 2, 4, 6, 8, or 24 h after LPS exposure. In a follow-up experiment, we assessed neural activation, as indexed by FOS immunohistochemistry, in the paraventricular nucleus of the hypothalamus (PVN) in prepubertal and adult males 0, 4, 8, or 24 h after a 0.1 mg/kg injection of LPS. By contrast to the prolonged response observed in prepubertal animals following a variety of acute stressors, we found that corticosterone and IL-6 responses induced by LPS recover toward baseline faster in prepubertal compared to adult rats. Along with these different peripheral responses, we also found that LPS-induced neural activation in the PVN of prepubertal animals showed a faster return to baseline compared to adults. Together, these data indicate that prepubertal and adult animals react in distinct ways, both peripherally and centrally, to an immunological stressor.
Goble
K H
KH
Department of Psychology and Neuroscience Behavior Program, Barnard College of Columbia University, New York, NY10027, USA.
Bain
Z A
ZA
Padow
V A
VA
Lui
P
P
Klein
Z A
ZA
Romeo
R D
RD
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000367:Age Factors; D000818:Animals; D003345:Corticosterone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D053583:Interleukin-1beta / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012741:Sexual Maturation / Q000276:immunology*; D013312:Stress, Physiological / Q000276:immunology*
D053583:Interleukin-1beta; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016760:Proto-Oncogene Proteins c-fos; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone