Dopaminergic control of aldosterone: modulation of the response of rat adrenal zona glomerulosa cells to alpha-Msh by pretreatment with bromocriptine or metoclopramide.
Bromocriptine treatment in rats (3 mg/kg per day, 7 days) significantly reduced alpha-msh and aldosterone plasma levels 2 hrs after the final treatment in animals on low, normal and high sodium diets. Alpha-MSH dose response curves for corticosterone and 18-hydroxydeoxycorticosterone (18-OH-DOC) in subsequently incubated glomerulosa cells gave stimulation at lower concentrations of alpha-MSH (10(-10) moles per litre) than in cells from untreated animals (10(-9) moles per 1). Curves for aldosterone (ald) and 18-hydroxycorticosterone (18-OH-B) were also affected in cells from animals on a low sodium diet. Fasciculata-reticularis cell responses to ACTH were unaffected. Metoclopramide (4 mg/kg per day, 7 days) elevated plasma alpha-MSH, although ald was unaffected, but inhibited the glomerulosa cell response to alpha-MSH in vitro. Acute dopaminergic responses in plasma ald may be mediated through alpha-MSH in rats, but chronically alpha-MSH may down- regulate glomerulosa cell alpha-MSH receptors. It is unlikely that alpha-MSH mediates the adrenocortical response to sodium depletion.
D000302:Adrenal Cortex / Q000187:drug effects* / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000097:blood*; D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D004039:Diet, Sodium-Restricted; D004305:Dose-Response Relationship, Drug; D005260:Female; D009074:Melanocyte-Stimulating Hormones / Q000097:blood / Q000494:pharmacology*; D008787:Metoclopramide / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D001971:Bromocriptine; D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D008787:Metoclopramide