The effect of salt-loading on corticotropin releasing hormone and arginine vasopressin mRNA levels in the mouse hypothalamus: a quantitative in situ hybridization analysis.
Previously, we showed that during salt-loading in mice there was an acute rise in plasma ACTH levels after 2 days followed by a transient decrease after 4 and 9 days. Pro-opiomelanocortin (POMC) mRNA levels in the anterior pituitary increased after 2 days and returned to normal thereafter. In this study, changes in hypothalamic CRH and AVP mRNA levels during salt-loading were investigated using quantitative in situ hybridization histochemistry. CRH mRNA was expressed only in the paraventricular nucleus (PVN), while AVP mRNA was expressed in both the supraoptic (SON) and paraventricular nuclei. CRH mRNA levels were unchanged after 2 days salt-loading, but declined to 77% of control levels after 9 days. AVP mRNA levels rose to 260% and 634% of control levels in the SON, and to 352% and 522% of control levels in the PVN, after 2 and 9 days salt-loading, respectively. These data suggest a major role of AVP in the acute stimulation of ACTH secretion and POMC mRNA levels seen after 2 days salt-loading. Desensitization of AVP receptors at the corticotroph level and a centrally mediated inhibition of CRH release may account for the decrease of ACTH secretion and POMC mRNA levels in the anterior pituitary with prolonged salt-loading.
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Section on Cellular Neurobiology, National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
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D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000096:biosynthesis* / Q000235:genetics; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000502:physiology; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012965:Sodium Chloride / Q000494:pharmacology*; D013495:Supraoptic Nucleus / Q000187:drug effects* / Q000378:metabolism
D012333:RNA, Messenger; D001127:Arginine Vasopressin; D012965:Sodium Chloride; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone