Simultaneous determination of intracellular free calcium and aldosterone production in bovine adrenal zona glomerulosa.
Angiotensin II (AII) induces an initial rapid but transient rise in [Ca2+]i detected with aequorin in bovine adrenal capsule strips. The rise in [Ca2+]i begins immediately after AII addition, reaches a peak in 30 seconds, and returns to near basal values within 5 minutes. The [Ca2+]i transient is receptor-mediated and its height is dose-dependent. The increase in [Ca2+]i is largely due to the release of Ca2+ from an intracellular pool. The uncorrected peak rise in [Ca2+]i after 1 X 10(-6) M beta-[asp1]-AII stimulation is approximately 3 fold, from 110 nM to 300 nM; the peak rise, corrected for diffusion and nonsynchronous cellular response, is from 110 nM to 1.2 microM. Perifusion of aequorin-loaded strips with beta-[asp1]-AII, an aminopeptidase-resistant analog of AII, allows the simultaneous measurement of [Ca2+]i and aldosterone production rate. Levels of agonist which generate a transient rise in [Ca2+]i also produce a sustained increase in aldosterone production rate, but the two events are temporally separated: the transient rise in [Ca2+]i precedes the increase in aldosterone production rate. However, there is a strong correlation, r = 0.94, between the amplitude of the initial [Ca2+]i transient and the magnitude of the sustained increase in steroid production rate.
Apfeldorf
W J
WJ
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.
Rasmussen
H
H
D000302:Adrenal Cortex / Q000378:metabolism; D000311:Adrenal Glands / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D000331:Aequorin; D000450:Aldosterone / Q000096:biosynthesis* / Q000378:metabolism; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D002417:Cattle; D008163:Luminescent Measurements; D010477:Perfusion; D013997:Time Factors
D000804:Angiotensin II; D000450:Aldosterone; D000331:Aequorin; D002118:Calcium