Effects of dopamine, high potassium concentration and field stimulation on the secretion of aldosterone by the perfused rat adrenal gland.
The rat adrenal cortex contains quantities of dopamine that are compatible with its function as a neurotransmitter, suggesting that locally released dopamine may act as a neuroregulator within the gland. This possibility has been tested by comparing the effects of dopamine on aldosterone secretion in the perfused adrenal with the effects of stimuli designed to provoke the release of intraglandular dopamine. Infusion of dopamine (0.1-100 mumol/l for 10-min periods) into the isolated perfused rat adrenal gland resulted in a transient, dose-related reduction of aldosterone secretion to a minimum of approximately 50% of the basal value at 1 mumol dopamine/l (ratio of experimental to control measurements, R = 0.53 +/- 0.06 (S.E.M.); n = 5). In contrast, dopamine (1-100 mumol/l) had no effect on aldosterone production by dispersed zona glomerulosa cell preparations incubated in vitro. The effects of changes in K+ concentration (3.9-52 mmol/l) on aldosterone secretion in the perfused gland and dispersed cell preparations were also compared. A similar bell-shaped dose-response relationship was seen in both preparations between 6 and 32 mmol K+/l, with a maximum at 8.4 mmol K+/l and a return to control values with 16, 24 or 32 mmol K+/l. However, infusion of media with very high K+ concentrations (42 or 52 mmol K+/l) reduced the secretion of aldosterone by the perfused gland to approximately 50% of the basal value (R = 0.51 +/- 0.05, n = 9; R = 0.49 +/- 0.08, n = 9; respectively) but produced no change in aldosterone production by zona glomerulosa cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Porter
I D
ID
Biomedical Sciences Division, King's College London, U.K.
Whitehouse
B J
BJ
Price
G M
GM
Hinson
J P
JP
Vinson
G P
GP
D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D000450:Aldosterone / Q000378:metabolism*; D000818:Animals; D004298:Dopamine / Q000494:pharmacology / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D008297:Male; D009924:Organ Culture Techniques; D011188:Potassium / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D000450:Aldosterone; D011188:Potassium; D004298:Dopamine