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Regulation of the hypothalamic-pituitary-adrenal axis during water deprivation.
Endocrinology. 1993 Jan; 132(1):241-8.E

Abstract

The contribution of the magnocellular vasopressinergic system to the regulation of ACTH secretion was studied by analysis of hypothalamic-adrenal axis function in rats subjected to water deprivation for 48 h. Water deprivation resulted in marked increases in plasma osmolarity and vasopressin (VP) levels and hypothalamic VP mRNA and immunoreactive (ir) VP in magnocellular neurons. While CRH mRNA levels in the paraventricular nucleus were decreased, irCRH accumulation in paraventricular nucleus neurons after colchicine treatment was normal or increased. Similarly, the irCRH content in the median eminence and its release under stress were similar in control and water-deprived rats. While basal plasma ACTH levels were similar in both groups (34.5 +/- 3.8 and 39.8 +/- 3.3 pg/ml), levels stimulated by CRH injection (10 micrograms, i.v.) or 15-min immobilization stress were reduced by 47% (P < 0.01) and 43% (P < 0.05), respectively, in water-restricted rats. The decreased ACTH responses were not prevented by injection of CRH (7.5 micrograms/day, sc) during the period of water deprivation. In contrast to the ACTH responses, basal and CRH-stimulated plasma corticosterone levels were significantly elevated (P < 0.001), and the responses to acute stress were normal. The inhibition of ACTH secretion was not due to increased glucocorticoid feedback, since similar blunted ACTH responses to acute immobilization stress were observed in adrenalectomized rats receiving corticosterone replacement. Despite similar levels of pituitary POMC mRNA, pituitary ACTH content was reduced in water-deprived rats, suggesting a posttranscriptional inhibition of POMC synthesis or processing. The data demonstrate that osmotic activation of the magnocellular VP system is accompanied by reduced responsiveness of the corticotrophs, an effect that is not due to increased glucocorticoid feedback or hypothalamic CRH deficiency. These findings suggest that the magnocellular vasopressinergic system does not play an important role in the regulation of ACTH secretion during chronic osmotic stimulation.

Authors+Show Affiliations

Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

8380375

Citation

Aguilera, G, et al. "Regulation of the Hypothalamic-pituitary-adrenal Axis During Water Deprivation." Endocrinology, vol. 132, no. 1, 1993, pp. 241-8.
Aguilera G, Lightman SL, Kiss A. Regulation of the hypothalamic-pituitary-adrenal axis during water deprivation. Endocrinology. 1993;132(1):241-8.
Aguilera, G., Lightman, S. L., & Kiss, A. (1993). Regulation of the hypothalamic-pituitary-adrenal axis during water deprivation. Endocrinology, 132(1), 241-8.
Aguilera G, Lightman SL, Kiss A. Regulation of the Hypothalamic-pituitary-adrenal Axis During Water Deprivation. Endocrinology. 1993;132(1):241-8. PubMed PMID: 8380375.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Regulation of the hypothalamic-pituitary-adrenal axis during water deprivation. AU - Aguilera,G, AU - Lightman,S L, AU - Kiss,A, PY - 1993/1/1/pubmed PY - 1993/1/1/medline PY - 1993/1/1/entrez SP - 241 EP - 8 JF - Endocrinology JO - Endocrinology VL - 132 IS - 1 N2 - The contribution of the magnocellular vasopressinergic system to the regulation of ACTH secretion was studied by analysis of hypothalamic-adrenal axis function in rats subjected to water deprivation for 48 h. Water deprivation resulted in marked increases in plasma osmolarity and vasopressin (VP) levels and hypothalamic VP mRNA and immunoreactive (ir) VP in magnocellular neurons. While CRH mRNA levels in the paraventricular nucleus were decreased, irCRH accumulation in paraventricular nucleus neurons after colchicine treatment was normal or increased. Similarly, the irCRH content in the median eminence and its release under stress were similar in control and water-deprived rats. While basal plasma ACTH levels were similar in both groups (34.5 +/- 3.8 and 39.8 +/- 3.3 pg/ml), levels stimulated by CRH injection (10 micrograms, i.v.) or 15-min immobilization stress were reduced by 47% (P < 0.01) and 43% (P < 0.05), respectively, in water-restricted rats. The decreased ACTH responses were not prevented by injection of CRH (7.5 micrograms/day, sc) during the period of water deprivation. In contrast to the ACTH responses, basal and CRH-stimulated plasma corticosterone levels were significantly elevated (P < 0.001), and the responses to acute stress were normal. The inhibition of ACTH secretion was not due to increased glucocorticoid feedback, since similar blunted ACTH responses to acute immobilization stress were observed in adrenalectomized rats receiving corticosterone replacement. Despite similar levels of pituitary POMC mRNA, pituitary ACTH content was reduced in water-deprived rats, suggesting a posttranscriptional inhibition of POMC synthesis or processing. The data demonstrate that osmotic activation of the magnocellular VP system is accompanied by reduced responsiveness of the corticotrophs, an effect that is not due to increased glucocorticoid feedback or hypothalamic CRH deficiency. These findings suggest that the magnocellular vasopressinergic system does not play an important role in the regulation of ACTH secretion during chronic osmotic stimulation. SN - 0013-7227 UR - https://www.unboundmedicine.com/medline/citation/8380375/Regulation_of_the_hypothalamic_pituitary_adrenal_axis_during_water_deprivation_ L2 - https://academic.oup.com/endo/article-lookup/doi/10.1210/endo.132.1.8380375 DB - PRIME DP - Unbound Medicine ER -