Control of steroidogenesis by the calcium messenger system in human adrenocortical cells

1991 ◽  
Vol 6 (1) ◽  
pp. 45-51 ◽  
Author(s):  
S. M. Laird ◽  
J. P. Hinson ◽  
G. P. Vinson ◽  
N. Mallick ◽  
S. Kapas ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Adrenal Cortex ◽  
Calcium Ionophore ◽  
Zona Glomerulosa ◽  
Adrenocortical Function ◽  
Ionophore A23187 ◽  
Adrenocortical Cells ◽  
Kinase C ◽  
Messenger System

ABSTRACT The involvement of the calcium messenger system in the control of steroidogenesis in the rat and bovine adrenal cortex has been studied extensively. However the role of these second messengers in the control of human adrenocortical function is not established. This was therefore studied by incubating collagenase-dispersed human adrenocortical cells with the calcium ionophore A23187 and the protein kinase C activator phorbol 12-myristate 13-acetate (TPA). The effects of the calcium channel blocker verapamil on basal and stimulated steroidogenesis were also studied. Both TPA (1 pmol/l–10 μmol/l) and A23187 (1 nmol/l–10 μmol/l) caused a dose-dependent increase in cortisol, aldosterone and corticosterone production. Verapamil (10 μmol/l) inhibited the increase in aldosterone, corticosterone and cortisol produced in response to ACTH(1–24), potassium, and desacetyl-αMSH. Unlike previous results in the rat, these effects were not specific for aldosterone secretion. The results suggest that, as in other species, calcium mobilization and protein kinase C activation have a role in the control of steroidogenesis in the human adrenal cortex. However, in contrast to the rat, these mechanisms appear to be involved in the control of steroidogenesis in both the zona glomerulosa and inner zone cells.

scholarly journals A role for protein kinase C in the membrane fusion necessary for platelet granule secretion

Blood ◽  
1989 ◽  
Vol 74 (7) ◽  
pp. 2405-2413 ◽  
Author(s):  
JM Gerrard ◽  
LL Beattie ◽  
J Park ◽  
SJ Israels ◽  
A McNicol ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Membrane Fusion ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ultrastructural Changes ◽  
Ionophore A23187 ◽  
Kinase C ◽  
Granule Secretion ◽  
Dimethyl Amiloride

Abstract The addition of 1-oleoyl-2-acetylglycerol (OAG), or phorbol-12- myristate-13-acetate (PMA) to platelets induced the phosphorylation of a 47,000 dalton protein (47 Kd), fusion of granule membranes with membranes of the surface connected canalicular system, the formation of large vesicles and the secretion of serotonin. 1-(5- isoquinolinesulfonyl)-2-methyl-piperazine (H7), and sphingosine, inhibitors of protein kinase C, significantly inhibited the ultrastructural changes and the phosphorylation of 47 Kd. N-(2- guanidinoethyl)-5-isoquinolinesulfonamide (HA1004), structurally similar to H7, but a weaker inhibitor of protein kinase C, did not attenuate these responses to OAG or to PMA. H7, but not HA1004, also markedly inhibited secretion induced by the synergistic combination of OAG and the calcium ionophore A23187. Amiloride and 5-(N,N dimethyl)- amiloride, inhibitors of the Na+/H+ transporter, did not inhibit the ultrastructural response and the protein phosphorylation induced by OAG, or the secretion induced by the combination of A23187 and OAG. The results link the activation of protein kinase C by diglycerides to the labilization and fusion of granule membranes important for secretion.

Protein kinase C activation and calcium mobilization decrease prolactin release from human decidual cells in early pregnancy

1993 ◽  
Vol 137 (2) ◽  
pp. 335-340 ◽  
Author(s):  
T. Kubota ◽  
S. Kamada ◽  
M. Taguchi ◽  
S. Sakamoto ◽  
T. Aso
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Early Pregnancy ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Calcium Mobilization ◽  
Ionophore A23187 ◽  
Prolactin Release ◽  
Kinase C ◽  
Decidual Cells

ABSTRACT The present study was undertaken to investigate the effects of protein kinase C (PKC) activation and calcium mobilization on the release of prolactin from human decidual cells in early pregnancy. Decidua obtained from patients in early pregnancy was enzymatically dispersed and cultured with phorbol myristate acetate (PMA) and calcium ionophore A23187 in a cell culture system. Prolactin in the medium was measured by enzyme-immunoassay. PMA, a PKC activator, dose-dependently attenuated the release of prolactin from cultured decidual cells, while a PKC inhibitor, H7, significantly (P < 0·001) diminished the effect of PMA on prolactin release. PMA had no effect on cell numbers or DNA synthesis in the decidual cells during culture. It did not significantly increase the generation of inositol phosphate in decidual cells prelabelled with myo[3H]inositol and it had no effect on intracellular calcium concentration ([Ca2 + ]i). Calcium ionophore A23187, a Ca2 +-mobilizing agent, also significantly (P<0·001) attenuated the release of prolactin and potentiated the PMA-induced suppression of prolactin release from decidual cells. These findings suggest that activation of PKC and mobilization of Ca2+ may be involved in regulating prolactin release from human decidual cells. The PMA-induced suppression of prolactin release is not triggered by phosphoinositide hydrolysis nor by the increase in [Ca2 + ]i in decidual cells. Journal of Endocrinology (1993) 137, 335–340

scholarly journals Protein kinase C regulates proliferation of mast cells and the expression of the mRNAs of fos and jun proto-oncogenes during activation by IgE-Ag or calcium ionophore A23187

Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2354-2364
Author(s):  
D Baranes ◽  
E Razin
Keyword(s):  
Protein Kinase C ◽  
Mast Cells ◽  
Protein Kinase ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Prolonged Treatment ◽  
Ionophore A23187 ◽  
Short Term ◽  
Kinase C ◽  
Short Term Exposure

Short-term stimulation (up to 16 hours) of interleukin-3 (IL-3)- dependent mouse bone marrow-derived mast cells, Abelson transformed mouse liver-derived mast cells, or rat basophilic leukemia cells by either IgE-Ag or calcium ionophore A23187 resulted in inhibition of their proliferation as measured by 3H-thymidine incorporation and MTT (tetrazolium) assays, and in accumulation of the mRNAs of c-fos, c-jun, junB and slightly of junD proto-oncogenes. The involvement of protein kinase C (PKC) in these responses was investigated by using several approaches of enzyme activity regulation. Direct activation of the PKC was achieved by short-term exposure of the cells to the PKC-specific activator phorbol 12-myristate-13-acetate (PMA). Inhibition of PKC activity was obtained by either prolonged treatment of the cells with PMA or by exposure of the cells to the PKC inhibitors H-7 and staurosporine. The results showed the following: (1) Short-term exposure of mast cells to PMA was sufficient to induce inhibition of proliferation. (2) An increase in PKC activity was associated with a decrease in the proliferation of IgE-dinitrophenol (DNP) or calcium ionophore A23187-stimulated cells. (3) A direct correlation was found between the increase in PKC activity and the increase in the level of the mRNAs of the jun proto-oncogenes in cells activated by both stimuli mentioned. (4) While an increase in PKC activity was associated with the upregulation of the level of c-fos mRNA during calcium ionophore A23187 stimulation, it showed the opposite effect on the expression of the mRNA of this proto-oncogene when the cells were triggered by IgE- DNP. Therefore, we concluded that PKC plays various roles in the expression of the mRNA of c-fos in activated mast cells depending on the stimulus involved. In addition, the expression of the mRNA of c-jun and junB proto-onogenes is not coordinately regulated with that of c- fos during immunologic stimulation. This discordancy, which is associated with the increase in PKC activity in mast cells, may play a role in the regulation of the transcription of AP-1-responsive genes, and therefore could be associated with the regulation of proliferation of these cells.

Modulation of histamine release from canine fundic mucosal mast cells

1988 ◽  
Vol 254 (1) ◽  
pp. G40-G48 ◽  
Author(s):  
A. H. Soll ◽  
M. Toomey ◽  
D. Culp ◽  
F. Shanahan ◽  
M. A. Beaven
Keyword(s):  
Protein Kinase C ◽  
Mast Cells ◽  
Protein Kinase ◽  
Histamine Release ◽  
Immunoglobulin E ◽  
Calcium Ionophore ◽  
Ionophore A23187 ◽  
Con A ◽  
Kinase C ◽  
Mucosal Mast Cells

To study the control of histamine release, we developed techniques for culturing fundic mucosal mast cells. After enzyme dispersion, enrichment by elutriation, and overnight suspension culture, mast cells accounted for 30% of the cells present. Histamine release into the medium, measured by radioenzymatic assay, was stimulated by the lectin concanavalin A (Con A). Ragweed antigen released histamine in antisera-sensitized cultures. Con A-induced histamine release was enhanced by adenosine, but adenosine alone was inactive. The relative potency of adenosine analogues was consistent with interaction at an adenosine A1-receptor site. The calcium ionophore A23187 (0.1-1 microM) also induced histamine release. Phorbol esters that activate protein kinase C, such as phorbol 12-myristate 13-acetate, did not release histamine but enhanced release when added to low concentrations of A23187. In contrast, inactive phorbols, such as 4 alpha-phorbol 12,13-didecanoate, failed to enhance A23187-induced release. Parallel studies with canine hepatic mast cells yielded comparable results. We conclude that canine fundic mast cells possess receptors for immunoglobulin E and adenosine. Our data are consistent with increases in cytosolic calcium and protein kinase C activation working synergistically to stimulate fundic mast cells.

scholarly journals Rapid expression of protooncogenes c-fos and c-myc in B-chronic lymphocytic leukemia cells during differentiation induced by phorbol ester and calcium ionophore

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1656-1663 ◽  
Author(s):  
HG Drexler ◽  
JW Janssen ◽  
MK Brenner ◽  
AV Hoffbrand ◽  
CR Bartram
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Chronic Lymphocytic Leukemia ◽  
Phorbol Ester ◽  
Messenger Rna ◽  
Calcium Ionophore ◽  
Lymphocytic Leukemia ◽  
Calcium Flux ◽  
Ionophore A23187 ◽  
Kinase C

Abstract The peripheral blood mononuclear cells from patients with B-chronic lymphocytic leukemia (B-CLL) were incubated for 0.5 h to 72 h in the presence of the phorbol ester TPA, the calcium ionophore A23187, or a combination of these reagents. Using Northern blot analysis, total cellular RNA was prepared from cells harvested at different time points and hybridized with DNA clones specific for the protooncogenes c-fos and c-myc. While untreated control cells lacked detectable amounts of messenger RNA (mRNA), increase in the level of c-fos mRNA was noted as early as 0.5 h after exposure to the inducers. Peaks of c-fos and c-myc transcript accumulation were seen at 1 h and 4 h after induction, respectively. The most effective inducer was double stimulation with TPA plus A23187. The kinetics of c-fos and c-myc mRNA accumulation in B- CLL appear to be similar to those reported for normal lymphocytes that have been either activated by physiologic external stimuli or by direct activators of protein kinase C and calcium flux (such as TPA and A23187). No direct link between oncogene expression and proliferation or differentiation parameters could be established. These results document that expression of c-fos and c-myc genes, which are among the earliest events following stimulation of the protein kinase signal transduction pathway, can be successfully induced in B-CLL cells. The data provide further evidence for the hypothesis that signal transmission downstream of protein kinase C is intact in B-CLL.

scholarly journals Regulation of endothelin-1- and lysophosphatidic acid-stimulated tyrosine phosphorylation of focal adhesion kinase (pp125fak) in Rat-1 fibroblasts

1994 ◽  
Vol 301 (2) ◽  
pp. 407-414 ◽  
Author(s):  
M K Saville ◽  
A Graham ◽  
K Malarkey ◽  
A Paterson ◽  
G W Gould ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Lysophosphatidic Acid ◽  
Calcium Ionophore ◽  
Mitogen Activated Protein Kinase ◽  
Ionophore A23187 ◽  
Endothelin 1 ◽  
Kinase C

The characteristics of protein tyrosine phosphorylation were examined in Rat-1 fibroblasts in response to endothelin-1 (ET-1) and 1-oleoyl-lysophosphatidic acid (LPA). Both agonists stimulated the biphasic tyrosine phosphorylation of at least three major proteins of approx. 120 kDa (pp116, pp120 and pp130) and two of 80 kDa (pp80 and pp70). Immunoprecipitation experiments indicated that the pp120 protein corresponded to the recently described focal adhesion protein kinase pp125fak. Phorbol 12-myristate 13-acetate, alone or in combination with the calcium ionophore A23187, also stimulated the phosphorylation of pp125fak but to a smaller extent than LPA or ET-1. Removal of both extracellular and intracellular Ca2+ did not significantly reduce LPA- and ET-1-stimulated tyrosine phosphorylation of pp125fak. In cells where protein kinase C activity was down-regulated or inhibited, ET-1-stimulated tyrosine phosphorylation of pp125fak was reduced to a greater extent than phosphorylation in response to LPA. In addition, ET-1-stimulated tyrosine phosphorylation of pp80 was decreased by 50-70% in response to protein kinase C inhibition at both 2 and 60 min whereas LPA-stimulated tyrosine phosphorylation of this protein was only reduced at 2 min. Pretreatment with pertussis toxin reduced the tyrosine phosphorylation of pp42 and pp44 forms of mitogen-activated protein kinase in response to both ET-1 and LPA but reduced the tyrosine phosphorylation of pp125fak only in response to LPA. These results indicate agonist-specific differences in the regulation of pathways mediating the tyrosine phosphorylation of pp125fak and other target proteins.

Regulation of aldosterone secretion by avian adrenocortical cells

1988 ◽  
Vol 118 (3) ◽  
pp. 447-453 ◽  
Author(s):  
J. Rosenberg ◽  
M. Pines ◽  
S. Hurwitz
Keyword(s):  
Protein Kinase C ◽  
Angiotensin Ii ◽  
Protein Kinase ◽  
Inositol Phosphate ◽  
Ionophore A23187 ◽  
Channel Blockers ◽  
Aldosterone Secretion ◽  
Adrenocortical Cells ◽  
Adrenal Cells ◽  
Kinase C

ABSTRACT Dispersed chick adrenocortical cells were incubated with mammalian and avian angiotensin-II, Ca2+, K+, verapamil, nifedipine, Ca2+ ionophore (A23187), protein kinase-C activator (phorbol 12-myristate 13-acetate; TPA), atrial natriuretic peptide (ANP), sodium nitroprusside (SNP) and ACTH. Secretion of aldosterone and corticosterone, and accumulation of cyclic nucleotides were assessed. Secretion of aldosterone was not affected by angiotensin-II, Ca2+ channel blockers, Ca2+ ionophore or TPA. ANP stimulated production of cyclic GMP (cGMP), and inhibited aldosterone secretion with a similar dose–response relationship. SNP also stimulated cGMP production and inhibited the ACTH-stimulated aldosterone secretion. The results indicate that ANP is an inhibitor of aldosterone secretion in birds and suggest that this inhibition is mediated by cGMP. In contrast to mammalian glomerulosa cells, angiotensin-II and the calcium-inositol phosphate-protein kinase C pathway appear not to be involved in the regulation of aldosterone secretion by avian adrenal cells. J. Endocr. (1988) 118, 447–453

Muscarinic regulation of potassium transport in a human submandibular epithelial cell line

1990 ◽  
Vol 259 (2) ◽  
pp. C340-C348 ◽  
Author(s):  
J. A. Ship ◽  
L. L. Patton ◽  
R. B. Wellner
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Epithelial Cell ◽  
Cell Line ◽  
Calcium Ionophore ◽  
Epithelial Cell Line ◽  
Ionophore A23187 ◽  
Muscarinic Agonist ◽  
Kinase C ◽  
86Rb Influx

Results of previous studies suggest that the transport of K+ by salivary ducts is under muscarinic control. The mechanisms by which this regulation occurs have not been well defined, however. In this paper, we describe mechanisms involved in the muscarinic regulation of K+ (86Rb) transport in HSG-PA, an epithelial cell line derived from human submandibular gland duct. Stimulation of HSG-PA cells by carbachol, a muscarinic agonist, increases both 86Rb influx and efflux, which results in a decrease in the equilibrium content of 86Rb within the cells. Increases in both fluxes are dose dependent with respect to carbachol concentration, and both responses can be blocked by atropine, a muscarinic antagonist. The carbachol-stimulated 86Rb fluxes appear to be calcium dependent since 1) the calcium ionophore A23187 increases 86Rb fluxes in these cells, 2) cells loaded with 1,2-bis(2-aminophenoxy)ethane- N,N,N',N'-tetraacetic acid (BAPTA; a calcium chelator) exhibit a reduced ability to respond to carbachol stimulation, and 3) removal of extracellular calcium concentration reduces the carbachol-stimulated effects. Treatment of HSG-PA cells with 10(-7) M phorbol myristate acetate (PMA) partially blocks the carbachol-stimulated changes in 86Rb fluxes, suggesting that protein kinase C plays a role in this response. PMA also partially blocks A23187-stimulated 86Rb influx, suggesting that activation of protein kinase C inhibits muscarinic-stimulated K+ influx by blocking either the Ca2+ signal (X. He, X. Wu, and B.J. Baum. Biochem. Biophys. Res. Commun. 152: 1062-1069, 1988), steps subsequent to this effect, or both.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of phorbol ester and calcium ionophore on chloride secretion in canine tracheal epithelium

1987 ◽  
Vol 253 (6) ◽  
pp. C828-C834 ◽  
Author(s):  
M. J. Welsh
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Calcium Ionophore ◽  
Tracheal Epithelium ◽  
Ionophore A23187 ◽  
Regulatory Pathway ◽  
Cl Secretion ◽  
Prostaglandin Production ◽  
Kinase C

The control of Cl- secretion was examined by two of the terminal events in the phosphoinositide regulatory pathway: activation of protein kinase C and an increase in cell Ca2+. The phorbol ester phorbol 12-myristate 13-acetate (PMA), which activates protein kinase C, stimulated Cl- secretion in both native and cultured monolayers of tracheal epithelium. Approximately 1.5 nM of mucosal PMA was required for half-maximal stimulation. Stimulation was not dependent on prostaglandin production nor was it accompanied by an increase in cellular levels of cAMP. Although the maximal rate of PMA-induced Cl- secretion was less than that induced by cAMP, there was a synergistic effect between PMA and forskolin, an agent that activates adenylate cyclase. The response to PMA was at least partly transient and PMA may also attenuate Cl- secretion under some circumstances. Thus the response to PMA, and presumably protein kinase C activation, may be complex. An increase in cell Ca2+ produced by addition of the Ca2+ ionophore A23187 also stimulated Cl- secretion. However, the effect was at least partly indirect. A23187 enhanced prostaglandin E2 production and the prostaglandin synthesis inhibitor, indomethacin, blocked A23187-induced secretion in native epithelia and attenuated the effect of A23187 in cultured monolayers. These results indicate the presence of a non-cAMP-dependent regulatory pathway capable of controlling Cl- secretion in tracheal epithelium. Activation of protein kinase C may stimulate secretion directly or modulate the response to cAMP. An increase in cell Ca2+ may stimulate secretion at least partly by stimulating endogenous prostaglandin production.

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