1. Differential Dependence of ACTH Secretion Induced by Various Cytokines on the Integrity of the Paraventricular Nucleus
- Author
-
Elenkov Ij and Kovács Kj
- Subjects
Male ,endocrine system ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Radioimmunoassay ,Alpha (ethology) ,Stimulation ,Lesion ,Cellular and Molecular Neuroscience ,Endocrinology ,Adrenocorticotropic Hormone ,Internal medicine ,medicine ,Animals ,Humans ,Secretion ,Rats, Wistar ,Beta (finance) ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Endocrine and Autonomic Systems ,business.industry ,Rats ,medicine.anatomical_structure ,Cytokines ,Tumor necrosis factor alpha ,Corticotropic cell ,medicine.symptom ,business ,Nucleus ,hormones, hormone substitutes, and hormone antagonists ,Interleukin-1 ,Paraventricular Hypothalamic Nucleus - Abstract
Effect of different cytokines, human recombinant interleukin-1 alpha and beta (IL-1 alpha, IL-1 beta), interleukin-6 and tumor necrosis factor-alpha (TNF) on adrenocorticotropin (ACTH) secretion was compared in sham-operated rats and those with lesions of the hypothalamic paraventricular nucleus. IL-1 alpha was less active than IL-1 beta in stimulating ACTH in sham-operated rats. Intravenous injection of IL-1 beta in sham-operated animals resulted in a rapid elevation of ACTH secretion. Five days after surgical lesion of the paraventricular nucleus, the main hypothalamic source of hypophysiotropic corticotropin-releasing factor-41, the response to IL-1 beta was attenuated but not abolished. This suggests involvement of extra-paraventricular releasing factors in mediation of ACTH-releasing activity of IL-1 beta, altered responsiveness of pituitary to CRFs, and/or direct action of IL-1 beta on the corticotrope cells. TNF resulted in a biphasic stimulation of ACTH concentration, with peaks at 15 min and 90 min. In paraventricular-lesioned, TNF injected rats both of these ACTH peaks disappeared, suggesting that CRFs from the paraventricular origin mediates ACTH-inducing activity of TNF. IL-6 elevated ACTH secretion much later than the other intravenously injected cytokines, the peak was at 1 h in sham-lesioned rats. Paraventricular lesion completely prevented the increase of ACTH plasma levels after IL-6 injection. These data suggest that: (1) Effect of TNF and IL-6 on hypothalamo-pituitary-adrenal axis is mediated through the hypothalamic paraventricular nucleus and (2) IL-1 beta is able to release ACTH even in the absence of hypothalamic drive.
- Published
- 1995
- Full Text
- View/download PDF