Anomalous adrenalectomy-induced Fos-like immunoreactivity in the hypothalamic paraventricular nucleus of stress-hyporesponsive rats.
Cellular activity in the paraventricular nucleus of the hypothalamus (PVN) in response to adrenalectomy (ADX) and sham-ADX was measured in adult male rats, lactating females, and nursing pups using c-fos immunocytochemistry. Increased Fos-like immunoreactivity (FLI) was seen in the PVN of male rats at 4 h following ADX or sham-ADX but this increase was transient, and basal values were restored within 24 h. In suckling pups, ADX induced a marked FLI response in the PVN at 3 days and at 18 days postpartum. At 11 days postpartum, however, the FLI response was attenuated relative to adult animals, and 3- and 18-day-old pups. Similarly, in nursing mothers, ADX induced FLI at 3 days, but this response disappeared by 7 days and did not reappear by the end of the suckling period (day 21). These data indicate that c-fos expression is a sensitive indicator of hyporesponsiveness in the hypothalamic-pituitary-adrenal (HPA) system.
Wintrip
N
N
Department of Obstetrics and Gynaecology, Grace Maternity Hospital, Halifax, NS, Canada.
Nance
D M
DM
Wilkinson
M
M
D000311:Adrenal Glands / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D000833:Animals, Suckling; D005260:Female; D007774:Lactation / Q000502:physiology; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000737:chemistry*; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000378:metabolism*
D016760:Proto-Oncogene Proteins c-fos