Long-term effects of hypothalamic paraventricular lesion on CRF content and stimulated ACTH secretion.
The effect of short-term (1 wk) and long-term (6 wk) lesion of the paraventricular nucleus (PVN) on the hypothalamopituitary-adrenal axis was studied. Six weeks after PVN lesion there was no change in resting morning plasma ACTH and corticosterone levels. The increase of plasma ACTH levels that occurs 8 days after adrenalectomy was inhibited 6 wk after placing a lesion in the PVN. In contrast, 6 wk after PVN lesion the plasma ACTH response measured 3 min after laparatomy and intestinal traction under ether anesthesia was not significantly different from that in the controls. The responsiveness to corticotropin-releasing factor (CRF)-41 of anterior pituitary segments incubated in vitro increased slightly at 6 wk after PVN lesion. The amount of CRF-41-like immunoreactive material in the stalk-median eminence decreased to approximately 14% of the control, while that in neural lobe failed to change. We suggest that the ACTH hypersecretion after adrenalectomy is driven predominantly by CRF-and/or AVP-producing neurons in and around the PVN, whereas other sources of CRF-41, increased pituitary sensitivity or other hypothalamic factors, may restore stress-induced ACTH release in the absence of the region of the PVN.
D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism; D003345:Corticosterone / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000502:physiology*; D051381:Rats; D013312:Stress, Physiological / Q000503:physiopathology; D013997:Time Factors
D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone