Angiotensin alters 45Ca2+ fluxes in bovine adrenal glomerulosa cells.

Elliott, Mary; Goodfriend, Theodore L.

doi:10.1073/pnas.78.5.3044

Cited by 33 publications

(9 citation statements)

References 41 publications

(44 reference statements)

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“…Furthermore, for ACTH, 5-HT and cyclic AMP stimulation of aldosterone production, modified Medium 199 produced either no change or a fall in the proportional response. These data, together with the failure of high concentrations of BSA to inhibit angiotensin II-stimulated steroidogenesis, are consistent with recent evidence that the mechanism by which angiotensin II stimulates steroidogenesis differs from that involved in K+ stimulation (Elliott & Goodfriend, 1981; Williams, McDougall, Tait & Tait, 1981).…”

Section: Discussionsupporting

confidence: 89%

Effect of composition of incubation medium on aldosterone and corticosterone production by isolated rat zona glomerulosa cells

Campbell¹

1982

Journal of Endocrinology

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The role of the composition of the incubation medium in determining the steroidogenic responsiveness of collagenase-dispersed rat zona glomerulosa cells was examined by studying the effect on production of aldosterone and corticosterone of (1) changes in the bovine serum albumin (BSA) concentration in Krebs\p=n-\Ringer bicarbonate buffer (KRBGA), (2) dialysis of the BSA and (3) comparison of KRBGA with 'modified' Medium 199. Medium 199 was modified so that its electrolytic content was identical to that of KRBGA.Compared with 0\ m=. \ 1\ p=n-\ 0\ m=. \ 2% BSA in KRBGA, BSA concentrations of 0\m=.\5and 4% caused inhibition of both basal and K+-stimulated, but not angiotensin II-stimulated steroidogenesis. This inhibitory property of BSA was not removed by dialysis. The BSA did, however, contain a dialysable factor which increased both basal steroidogenesis and the steroidogenic response to maximal K+ and angiotensin II stimulation.Both incubation media contained 0\m=.\2% BSA for the comparison of KRBGA with modified Medium 199. Modified Medium 199 increased both basal steroidogenesis and the aldosterone response to K+ stimulation (per cent increase above basal) by two-to threefold compared with KRBGA, with smaller increases in the response to ACTH and 5\ x =r eq-\ hydroxytryptamine (5-HT) and a decrease in the response to cyclic AMP. In contrast, modified Medium 199 increased the aldosterone response to angiotensin II by sevenfold, from 60% (in KRBGA) to 420%.In KRBGA, angiotensin II inhibited K+-stimulated aldosterone production. This effect was produced by concentrations of angiotensin II below the threshold for steroidogenesis and could be reproduced with the angiotensin II antagonist [Sar1, Ileu8]-angiotensin II.These data emphasize the importance of the composition of the incubation medium in determining the steroidogenic responsiveness of rat zona glomerulosa cells in vitro. Furthermore, these data indicate that the steroidogenic response to angiotensin II, compared with K +, ACTH, 5-HT and cyclic AMP, is more readily influenced by other, as yet unidentified, factors in the incubation medium, and are consistent with recent evidence that angiotensin II and K+ do not share a common mode of action on steroidogenesis by these cells.

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Section: Discussionsupporting

confidence: 89%

Effect of composition of incubation medium on aldosterone and corticosterone production by isolated rat zona glomerulosa cells

Campbell¹

1982

Journal of Endocrinology

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“…Some reports showed an increase in the Ca 2+ influx rate during A II stimulation (4, 10-12), while others found no change in the Ca 2+ influx rate under similar conditions (13,14). Where an increase in…”

Section: )mentioning

confidence: 95%

“…Some reports showed an increase in the Ca 2+ influx rate during A II stimulation (4,(10)(11)(12), while others found no change in the Ca 2+ influx rate under similar conditions (13,14). Where an increase in Ca 2+ influx is observed, evidence points to the activation of voltage-dependent Ca 2+ conductance.…”

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confidence: 91%

Electrophysiological Responses to Angiotensin II of Isolated Rat Adrenal Glomerulosa Cells*

1987

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The membrane response of isolated rat glomerulosa cells to the application of angiotensin II (A II) has been studied using intracellular voltage measurements. The membrane response is biphasic. The first, brief phase involves an increase in membrane conductance and a hyperpolarization from the resting membrane potential. The second, long-lasting phase is characterized by a large decrease in membrane conductance and a depolarization from the resting membrane potential. The reversal potential for the second phase is -94 +/- 1.2 mV, and a linear relationship between reversal potential and external K+ indicates that the A II-mediated response is predominantly inhibition of K+ permeability. The A II response can be elicited when external Ca2+ is replaced by Sr2+ or Ba2+, but the response is inhibited when Mn2+ is added to the bath or when stimulated in a Ca2+-free solution. A II appears to inhibit at least two conductances, when the cell is stimulated by long current steps. External application of A II inhibited the Ca2+ regenerative response found in glomerulosa cells in a dose-dependent manner. The rate of rise of the regenerative response was greatly attenuated by A II; half-maximal inhibition was produced by about 10(-9) M A II. In addition, rectification, evident at voltages more positive than -60 mV during current stimulation, was also inhibited. In conclusion, A II causes rat glomerulosa cells to depolarize due to the inhibition of resting K+ permeability. Action potential activity is not observed during A II-mediated membrane depolarization; rather, both Ca2+ and K+ conductances appear to be inhibited during A II application.

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“…On the other hand, applied at lower (sub-nanomolar) concentration, AII could also enhance the inactivation of a Ca2+-entry mechanism or activate Ca2è xtrusion, thereby determining the steady-state cytoplasmic Ca2+ concentration. Activation of Ca2+ efflux by AII in adrenal glomerulosa cells has been described previously [23,24], together with the ability of the hormone to decrease total or exchangeable Ca2+ content of the cells [23,25,26].…”

Section: Discussionmentioning

confidence: 99%

Angiotensin II inhibits K+-induced Ca2+ signal generation in rat adrenal glomerulosa cells

Balla

Holló

Várnai

et al. 1991

Biochemical Journal

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The Ca2+-mobilizing hormone angiotensin II (All) dose-dependently inhibited the K+-induced sustained increase of cytoplasmic Ca2+ concentration in adrenal glomerulosa cells and caused a rapid decrease of cytoplasmic Ca2+ when added to cells already stimulated with K+. These effects of All on the K+-induced Ca2+ signal were mimicked, although less effectively, by other Ca2+-mobilizing agonists such as [Arg8]vasopressin (AVP) and thapsigargin. Phorbol esters did not show such effects, nor did corticotropin (ACTH), a secretagogue acting via cyclic AMP. The K+-stimulated initial 45Ca2+ uptake, a measure of Ca2+ entry into glomerulosa cells, was also prevented by All pretreatment, and was inhibited by AVP, but not by ACTH. The stimulatory effect of K+ on aldosterone production, however, was not inhibited by All, and the AII-induced aldosterone production was further increased by increasing K+. These data indicate that All is able to inhibit static increases in cytoplasmic Ca2+ by inhibiting Ca2+ entry through voltage-sensitive Ca2+ channels and, possibly, by activating Ca2+ extrusion from the cells. It is also concluded that the Ca2+ signal evoked by All is very efficient in stimulating hormone secretion, and the secretory response of the cells becomes more sensitive to any further increase of Ca2+ entry through voltage-sensitive Ca2+ channels.

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Angiotensin alters 45Ca2+ fluxes in bovine adrenal glomerulosa cells.

Cited by 33 publications

References 41 publications

Effect of composition of incubation medium on aldosterone and corticosterone production by isolated rat zona glomerulosa cells

Effect of composition of incubation medium on aldosterone and corticosterone production by isolated rat zona glomerulosa cells

Electrophysiological Responses to Angiotensin II of Isolated Rat Adrenal Glomerulosa Cells*

Angiotensin II inhibits K+-induced Ca2+ signal generation in rat adrenal glomerulosa cells

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