title: Effects of bromocriptine on the circadian rhythm of 18-hydroxycorticosterone and cortisol secretion in essential hypertensives.
abstract: This study examines the influence of bromocriptine, a dopamine agonist, on circadian secretory patterns of plasma 18-hydroxycorticosterone (18-OHB) and cortisol in essential hypertension. Patients with sustained essential hypertension were studied after they had reached equilibrium on a constant 150 mmol sodium and 80 mmol potassium intake. Plasma 18-OHB and cortisol determinations were made at 30-min intervals over 24 h during a control and bromocriptine treatment period (bromocriptine, 2.5 mg t.i.d. for five days). Circadian patterns for plasma 18-OHB and cortisol were observed in all patients before and after bromocriptine. Although bromocriptine did not affect the circadian rhythm of 18-OHB and cortisol it did decrease mean 24-h recumbent 18-OHB from 23 +/- 42.2 to 14.3 +/- 1.4 ng/dl. These results suggest that there is a circadian rhythm of both 18-OHB and cortisol secretion in patients with essential hypertension as in normotensives. Dopaminergic mechanisms exert an effect on the quantitative secretion of 18-OHB. However, the circadian rhythm for 18-OHB and cortisol does not appear to be dependent on dopaminergic mechanisms.
mesh_terms: D015069:18-Hydroxycorticosterone / Q000378:metabolism*; D000328:Adult; D000450:Aldosterone / Q000378:metabolism; D001971:Bromocriptine / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects*; D003345:Corticosterone / Q000031:analogs & derivatives*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
chemical_list: D001971:Bromocriptine; D000450:Aldosterone; D015069:18-Hydroxycorticosterone; D003345:Corticosterone; D006854:Hydrocortisone