Biomaterial Database

Influence of sodium homeostasis and circadian rhythm on dopaminergic modulation of 18-hydroxycorticosterone secretion in man. 1982

J R Sowers, and N Stern

This study examines the effects of sodium homeostasis and circadian rhythm on plasma 18-hydroxycorticosterone (18-OHB) responses to the dopamine antagonist metoclopramide in seven normal individuals. Responses to metoclopramide were evaluated after receiving a 10-meq sodium diet, a 100-meq sodium diet, and a 200-meq sodium diet for 5 days. On all three occasions the subjects had reached sodium equilibrium states, as determined by urinary sodium measurements, at the time that they received metoclopramide. Percentage incremental 18-OHB responses to metoclopramide were greater (P less than 0.01) in the subjects after 5 days on a 200-meq sodium intake than after 5 days on a 10-meq sodium intake. The percentage increases in plasma 18-OHB after a 200-meq sodium intake were slightly greater (P less than 0.05) than increases after a 100-meq sodium intake. Plasma 18-OHB levels demonstrated a circadian rhythm, with plasma levels reaching their zenith during the later part of sleep and shortly after awakening and reaching their nadir between 2000 and 2400 h. Although basal levels of 18-OHB at 2200 h (15.5 +/- 1.6 ng/dl) were considerably lower (P less than 0.01) than basal levels of 18-OHB at 0800 h, the 18-OHB responses to metoclopramide were similar at 0800 and 2200 h. Administration of the dopamine agonist bromocriptine (2.5 mg three times a day for 4 days) suppressed (P less than 0.01) mean 24-h plasma 18-OHB levels from 21.9 +/- 2.0 to 14.8 +/- 1.4 ng/dl. However, bromocriptine did not alter the circadian rhythm of 18-OHB secretion. These data suggest that increased sodium intake leads to greater tonic dopaminergic inhibition of 18-OHB secretion. Although dopaminergic mechanisms modulate 18-OHB secretion, they do not govern the circadian rhythm of this corticosteroid.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008787	Metoclopramide	A dopamine D2 antagonist that is used as an antiemetic.	4-Amino-5-chloro-N-(2-(diethylamino)ethyl)-2-methoxybenzamide,Cerucal,Maxolon,Metaclopramide,Metoclopramide Dihydrochloride,Metoclopramide Hydrochloride,Metoclopramide Monohydrochloride,Metoclopramide Monohydrochloride, Monohydrate,Primperan,Reglan,Rimetin,Dihydrochloride, Metoclopramide,Hydrochloride, Metoclopramide,Monohydrochloride, Metoclopramide
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D012084	Renin-Angiotensin System	A BLOOD PRESSURE regulating system of interacting components that include RENIN; ANGIOTENSINOGEN; ANGIOTENSIN CONVERTING ENZYME; ANGIOTENSIN I; ANGIOTENSIN II; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming ANGIOTENSIN I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to ANGIOTENSIN II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal VASCULAR SMOOTH MUSCLE, leading to retention of salt and water in the KIDNEY and increased arterial blood pressure. In addition, angiotensin II stimulates the release of ALDOSTERONE from the ADRENAL CORTEX, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down BRADYKININ, a powerful vasodilator and component of the KALLIKREIN-KININ SYSTEM.	Renin-Angiotensin-Aldosterone System,Renin Angiotensin Aldosterone System,Renin Angiotensin System,System, Renin-Angiotensin,System, Renin-Angiotensin-Aldosterone
D001971	Bromocriptine	A semisynthetic ergotamine alkaloid that is a dopamine D2 agonist. It suppresses prolactin secretion.	2-Bromoergocryptine,Bromocryptin,2-Bromo-alpha-ergocryptine,2-Bromo-alpha-ergokryptine,2-Bromoergocryptine Mesylate,2-Bromoergocryptine Methanesulfonate,2-Bromoergokryptine,Bromocriptin,Bromocriptine Mesylate,CB-154,Parlodel,2 Bromo alpha ergocryptine,2 Bromo alpha ergokryptine,2 Bromoergocryptine,2 Bromoergocryptine Mesylate,2 Bromoergocryptine Methanesulfonate,2 Bromoergokryptine,CB 154,CB154,Mesylate, 2-Bromoergocryptine,Mesylate, Bromocriptine,Methanesulfonate, 2-Bromoergocryptine
D002940	Circadian Rhythm	The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs or environmental and physiological stimuli.	Diurnal Rhythm,Nyctohemeral Rhythm,Twenty-Four Hour Rhythm,Nycthemeral Rhythm,Circadian Rhythms,Diurnal Rhythms,Nycthemeral Rhythms,Nyctohemeral Rhythms,Rhythm, Circadian,Rhythm, Diurnal,Rhythm, Nycthemeral,Rhythm, Nyctohemeral,Rhythm, Twenty-Four Hour,Rhythms, Circadian,Rhythms, Diurnal,Rhythms, Nycthemeral,Rhythms, Nyctohemeral,Rhythms, Twenty-Four Hour,Twenty Four Hour Rhythm,Twenty-Four Hour Rhythms
D003345	Corticosterone	An adrenocortical steroid that has modest but significant activities as a mineralocorticoid and a glucocorticoid. (From Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1437)
D004298	Dopamine	One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.	Hydroxytyramine,3,4-Dihydroxyphenethylamine,4-(2-Aminoethyl)-1,2-benzenediol,Dopamine Hydrochloride,Intropin,3,4 Dihydroxyphenethylamine,Hydrochloride, Dopamine
D006706	Homeostasis	The processes whereby the internal environment of an organism tends to remain balanced and stable.	Autoregulation