cyclic-gmp and Adrenal-Cortex-Neoplasms

Topics: Adrenal Cortex; Adrenal Cortex Neoplasms; Adrenocorticotropic Hormone; Angiotensin II; Animals; Cyclic AMP; Cyclic GMP; Humans; Nucleotides, Cyclic; Nutritional Physiological Phenomena; Phosphorylation; Prostaglandins; Protein Kinases; Steroids

In this study, we demonstrate that B-type natriuretic peptide (BNP) opposed angiotensin II (Ang II)-stimulated de novo cholesterol biosynthesis, cellular cholesterol uptake, cholesterol transfer to the inner mitochondrial membrane, and steroidogenesis, which are required for biosynthesis of steroid hormones such as aldosterone and cortisol in primary human adrenocortical cells. BNP dose-dependently stimulated intracellular cGMP production with an EC(50) of 11 nm, implying that human adrenocortical cells express the guanylyl cyclase A receptor. cDNA microarray and real-time RT-PCR analyses revealed that BNP inhibited Ang II-stimulated genes related to cholesterol biosynthesis (acetoacetyl coenzyme A thiolase, HMG coenzyme A synthase 1, HMG coenzyme A reductase, isopentenyl-diphosphate Delta-isomerase, lanosterol synthase, sterol-4C-methyl oxidase, and emopamil binding protein/sterol isomerase), cholesterol uptake from circulating lipoproteins (scavenger receptor class B type I and low-density lipoprotein receptor), cholesterol transfer to the inner mitochondrial membrane (steroidogenic acute regulatory protein), and steroidogenesis (ferredoxin 1,3beta-hydroxysteroid dehydrogenase, glutathione transferase A3, CYP19A1, CYP11B1, and CYP11B2). Consistent with the microarray and real-time PCR results, BNP also blocked Ang II-induced binding of (125)I-labeled low-density lipoprotein and (125)I-labeled high-density lipoprotein to human adrenocortical cells. Furthermore, BNP markedly inhibited Ang II-stimulated release of estradiol, aldosterone, and cortisol from cultured primary human adrenocortical cells. These findings demonstrate that BNP opposes Ang II-induced steroidogenesis via multiple steps from cholesterol supply and transfer to the final formation of steroid hormones. This study provides new insights into the cellular mechanisms by which BNP modulates Ang II-induced steroidogenesis in the adrenal gland.

Topics: Adrenal Cortex; Adrenal Cortex Hormones; Adrenal Cortex Neoplasms; Adrenocortical Carcinoma; Adult; Angiotensin II; Cell Line, Tumor; Cells, Cultured; Cholesterol; Cyclic GMP; Drug Interactions; Gene Expression Profiling; Gene Expression Regulation; Humans; Lipoproteins; Male; Middle Aged; Natriuretic Peptide, Brain; Oligonucleotide Array Sequence Analysis; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Steroids; Vasoconstrictor Agents

The inhibitory effect of atrial natriuretic peptide (ANP) on angiotensin II (AII)-stimulated aldosterone secretion has been previously studied in rat and bovine adrenal zona glomerulosa cells in primary culture. However the understanding of the mode of action of ANP at the molecular level has been hampered by limitations of those primary cell culture systems and by the lack of cell lines from human adrenal cortex. Here we demonstrate the presence of fully functional ANP receptors in the recently characterized AII-responsive adrenocortical carcinoma cell line H295R. Specific saturable binding of 125I-rANP to H295R cell membrane preparations revealed a single class of high affinity binding sites with a density of 20 fmol/mg of protein. The pharmacological profile of this ANP receptor was documented by competitive binding of 125I-rANP with naturally occurring natriuretic peptides. rANP was the most potent with a Kd of 42 pM. pBNP32 was less potent with a Kd of 174 pM. 125I-rANP binding was not competed by pCNP (NPRB-specific ligand) nor by C-ANF (NPRC-specific ligand). Photoaffinity labeling of membrane preparations with 125I-BPA-ANP revealed a single specific protein of molecular weight around 130 kDa. This protein was further identified by immunodetection with a specific antibody directed to the human ANP-specific receptor NPRA. Natriuretic peptides stimulated cGMP production by the receptor-coupled guanylate cyclase with the same specificity. Aldosterone production by AII-stimulated H295R cells was dose-dependently inhibited by rANP with an ED50 of 1.5 nM. In addition, we used this model to test two chimeric analogs of ANP and BNP. pBNP1 and pBNP3 were, respectively, 4- and 2-fold more potent than rANP in competing for 125I-rANP binding with Kd of 10 and 20 pM. pBNP1 was 24-fold more potent in inhibiting AII-stimulated aldosterone production with ED50 of 63 pM. pBNP1 is therefore the most potent natriuretic peptide analog tested. In summary, the human H295R cell line contains NPRA receptors positively coupled to the particulate guanylate cyclase and that antagonize angiotensin II stimulation of aldosterone secretion.

Topics: Adrenal Cortex; Adrenal Cortex Neoplasms; Aldosterone; Atrial Natriuretic Factor; Biological Assay; Cyclic GMP; Humans; Receptors, Atrial Natriuretic Factor; Recombinant Proteins; Tumor Cells, Cultured

The effects of atrial natriuretic peptide (ANP) on adrenocortical fasciculata cells were examined in the ACTH-responsive Y-1 mouse adrenocortical tumor cell line. Y-1 cell membranes rapidly bound [125I]ANP, with equilibrium binding (22 C) reached within 45 min. Binding of [125I]ANP was inhibited in a concentration-dependent manner by unlabeled ANP and atriopeptin-I (IC50, approximately 1.2 X 10(-9) and 1.6 X 10(-8) M, respectively), but not by C- or N-terminal-deleted ANP fragments, ACTH, or arginine vasopressin (up to 10(-6) M). Scatchard analysis revealed a single class of high affinity binding sites with a Kd of 1.6 X 10(-10) M and a binding capacity of 560 fmol/mg protein. Photo-affinity labeling demonstrated the specific binding of ANP to two protein entities of 130 and 63 kDa. ANP stimulated both cGMP synthesis and secretion from Y-1 cells (EC50, approximately 3.5 X 10(-9) M). Release of the nucleotide was inhibited by probenecid (IC50, approximately 5 X 10(-5) M). The atrial peptide partially inhibited ACTH-stimulated cAMP formation (IC50, approximately 10(-8) M) and partially antagonized basal and ACTH-stimulated steroidogenesis. The data demonstrate the presence in Y-1 cells of specific and saturable ANP receptors, activation of which leads to changes in cyclic nucleotide metabolism and inhibition of steroidogenesis.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Adrenal Cortex Neoplasms; Adrenocorticotropic Hormone; Animals; Atrial Natriuretic Factor; Binding, Competitive; Cell Line; Cell Membrane; Corticosterone; Cyclic AMP; Cyclic GMP; Kinetics; Mice; Probenecid; Receptors, Atrial Natriuretic Factor; Receptors, Cell Surface

The effects of synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) on cortisol secretion by adrenocortical adenoma cells from patients with Cushing's syndrome (CS cells) in primary monolayer cultures, compared to cultured normal adrenal cells, were studied. alpha-hANP significantly inhibited cortisol secretion by human normal adrenal cells in culture, but had no direct effect on cortisol secretion from CS cells, in the presence or absence of 10(-8) M ACTH. alpha-hANP enhanced the accumulation of intracellular cyclic GMP in normal adrenal cells in culture, but not in CS cells. Visualization of [125I] iodo-alpha-hANP-specific binding sites by an in vitro receptor autoradiographic technique showed that these sites were lacking in adrenocortical adenoma tissues. These results suggest that the loss of alpha-hANP inhibitory effect on cortisol secretion in CS cells may be due to the absence of alpha-hANP receptor sites.

Topics: Adenoma; Adrenal Cortex Neoplasms; Adrenal Glands; Adult; Aldosterone; Atrial Natriuretic Factor; Cells, Cultured; Cushing Syndrome; Cyclic GMP; Female; Humans; Hydrocortisone; Middle Aged; Peptide Fragments; Tumor Cells, Cultured

Rat adrenocortical carcinoma cells possess a high density of atrial natriuretic factor (ANF) receptors which are coupled with membrane guanylate cyclase and corticosterone production. Herein we show that pretreatment of these cells with phorbol 12-myristate 13-acetate (PMA), a known activator of protein kinase C, attenuates the ANF-stimulated cyclic GMP accumulation in a dose-dependent manner. The half maximum inhibitory concentration of PMA was 10(-10) M. When these cells were incubated with PMA in the presence of 1-(5-isoquinolinyl-sulfonyl)-2-methyl piperazine, a protein kinase C inhibitor, the PMA-mediated attenuation of ANF-stimulated cyclic GMP formation is blocked. These results suggest that protein kinase C negatively regulates the ANF-receptor coupled membrane guanylate cyclase system in these cells.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Adrenal Cortex Neoplasms; Animals; Atrial Natriuretic Factor; Cyclic GMP; Enzyme Activation; Guanylate Cyclase; Isoquinolines; Phosphorylation; Piperazines; Protein Kinase C; Rats; Receptors, Atrial Natriuretic Factor; Receptors, Cell Surface; Tetradecanoylphorbol Acetate

alpha 2-adrenergic receptor-mediated signal transduction in rat adrenocortical carcinoma cells occurs through the opposing regulation of two second messengers, cyclic GMP and cyclic AMP, in which guanylate cyclase is coupled positively and adenylate cyclase negatively to the receptor signal. We now show that in these cells phorbol 12-myristate 13-acetate (PMA), a known activator of protein kinase C, inhibits the alpha 2-agonist (p-aminoclodine)-dependent production of cyclic GMP in a dose-dependent and time-dependent fashion. The half-maximal inhibitory concentration of PMA was 10(-10) M. A protein kinase C inhibitor, 1-(5-isoquinolinyl-sulfonyl)-2-methyl piperazine (H-7), caused the release of the PMA-dependent attenuation of p-aminoclodine-stimulated cyclic GMP formation. These results suggest that protein kinase C negatively regulates the alpha 2-receptor coupled cyclic GMP system in these cells, a feature apparently shared with the other cyclic GMP-coupled receptors such as those of muscarine, histamine, and atrial natriuretic factor.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Adrenal Cortex Neoplasms; Animals; Carcinoma; Clonidine; Cyclic GMP; Dose-Response Relationship, Drug; Enzyme Activation; Guanylate Cyclase; Isoquinolines; Kinetics; Piperazines; Protein Kinase C; Rats; Receptors, Adrenergic, alpha; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

Isolated adrenocortical carcinoma cells of rat contain alpha 2- and beta-adrenergic receptors. When these cells are incubated with alpha 2-adrenergic agonists, there is a concentration-dependent increase of cyclic GMP that is blocked by the alpha 2-adrenergic antagonist yohimbine but not by the beta-antagonist propranolol. Concomitantly, both p-aminoclonidine (20 microM) and clonidine (100 microM), the alpha 2-adrenergic agonists, stimulate membrane guanylate cyclase activity. In calcium free medium there is no alpha 2-agonist-dependent increase in cyclic GMP. Isoproterenol, a beta-agonist, and forskolin cause an increase in cyclic AMP but not cyclic GMP. The cyclic AMP increase induced by isoproterenol is blocked by propranolol but not by yohimbine. Isoproterenol- and forskolin-dependent increases in cyclic AMP are inhibited by p-aminoclonidine and the inhibition is relieved by yohimbine. These results indicate a dual regulation of guanylate cyclase and adenylate cyclase by the alpha 2-receptor signal: guanylate cyclase is coupled to the receptor in a positive fashion, whereas adenylate cyclase is coupled in a negative fashion. Calcium is obligatory in the cyclic GMP-mediated response.

Topics: Adenylyl Cyclases; Adrenal Cortex Neoplasms; Animals; Cyclic AMP; Cyclic GMP; Guanylate Cyclase; Rats; Receptors, Adrenergic, alpha; Receptors, Adrenergic, beta

Isolated fasciculata cells of rat adrenal cortex, when incubated with atrial natriuretic factor (ANF), stimulated the levels of cyclic GMP and corticosterone production in a concentration-dependent manner without a rise in the levels of cyclic AMP. The ANF-dependent elevation of cyclic GMP was rapid, with a detectable increment in 30 s. ANF also stimulated the particulate guanylate cyclase. These results not only indicate the coupling of cyclic GMP and corticosterone production with ANF signal, but also demonstrate that, like the ACTH signal, cyclic AMP is not the mediator of ANF-induced adrenocortical steroidogenesis.

Topics: Adrenal Cortex; Adrenal Cortex Neoplasms; Animals; Atrial Natriuretic Factor; Carcinoma; Corticosterone; Cyclic AMP; Cyclic GMP; Rats; Stimulation, Chemical

The effects of synthetic alpha-human atrial natriuretic polypeptide (alpha hANP) on aldosteronogenesis in normal and aldosterone-producing adenoma cells (APA cells) in primary monolayer cultures were studied. alpha hANP significantly inhibited aldosterone secretion from normal adrenal cells in culture, but had no inhibitory effect on aldosterone secretion from APA cells in the presence or absence of 10(-8) M ACTH. alpha hANP enhanced the accumulation of intracellular cGMP in normal adrenal cells in culture, but not in APA cells. Visualization of [125I]iodo-alpha hANP-specific binding sites in APA and adjacent normal adrenal tissues by an in vitro receptor autoradiographic technique showed that these sites were localized only in normal adrenal tissue, but not in APA tissue. These results suggest that the lack of an inhibitory effect of alpha hANP on aldosteronogenesis in APA cells may be due to the absence of alpha hANP-specific receptor sites in APA cells.

Topics: Adenoma; Adrenal Cortex Neoplasms; Adult; Aldosterone; Atrial Natriuretic Factor; Autoradiography; Cells, Cultured; Cyclic GMP; Female; Humans; Middle Aged; Radioligand Assay; Receptors, Atrial Natriuretic Factor; Receptors, Cell Surface

Primary cultures of dissociated parenchymal cells from Conn's adenomata causing primary hyperaldosteronism were successfully set up by a method previously used with normal adult human and rat adrenocortical tissue. In such cultures the adenomatous cells largely prevailed (making up 87% of the whole cell population), could survive for lengthy terms (at least up to 30 days), and were endowed with a spontaneous, discrete capability to proliferate. The de novo RNA- and DNA-synthetic and mitotic activities of Conn's cells were markedly stimulated in cultures exposed between 16 and 21 to daily doses of exogenous cyclic AMP, either alone or in equimolar association with cyclic GMP. A significantly weaker, though still prominent enhancement of adenomatous cell growth was elicited also by daily administrations of an equimolar mixture of ACTH1-24 and angiotensin II. In contrast, little stimulation or inhibition of growth or no effect at all could be observed when cyclic GMP, ACTH1-24, and angiotensin II were respectively administered, each by itself.

Topics: Adrenal Cortex Neoplasms; Adrenocorticotropic Hormone; Angiotensin II; Cell Division; Cosyntropin; Culture Techniques; Cyclic AMP; Cyclic GMP; Humans; Hyperaldosteronism; Time Factors

In the normal adrenal cell, epinephrine does not activate the rise of either cGMP or cAMP concentrations. In contrast, epinephrine activates the rise of cGMP but not cAMP concentrations in a concentration-dependent manner in isolated adrenocortical carcinoma cells. This effect was duplicated by the alpha-adrenergic agonist, phenylepherine, but was unaffected by the beta-adrenergic agonist, isoproterenol. The epinephrine-activated increase in cGMP was blocked by the alpha-adrenergic antagonist, phentolamine, but was not interfered with by the beta-adrenergic antagonist, propranolol. Neither acetylcholine, a cholinergic agonist, nor exogenous calcium caused any increase in cGMP. The rise of cGMP maximally activated by ACTH was additive with that obtained with epinephrine. These results indicate that the adrenal neoplastic cell possesses ectopic alpha-adrenergic receptors, and that epinephrine causes a rise of the cGMP level through these receptors. The data, furthermore, suggest that the receptors for ACTH and epinephrine are distinct.

Topics: Acetylcholine; Adrenal Cortex Neoplasms; Adrenocorticotropic Hormone; Animals; Atropine; Cell Line; Cyclic AMP; Cyclic GMP; Dose-Response Relationship, Drug; Epinephrine; Isoproterenol; Phentolamine; Phenylephrine; Propranolol; Rats

The decline of the ACTH-stimulated cGMP to the basal level in isolated adrenocortical carcinoma cells was inhibited by cyclic phosphodiesterase inhibitors. Time-course experiments showed that the ACTH-induced level of cGMP preceded the activation of phosphodiesterase. Cells incubated with increasing concentrations of exogenous cGMP responded with a corresponding increase in the cGMP-phosphodiesterase activity. cAMP was 100-fold less effective than cGMP in the activation of cGMP-phosphodiesterase, indicating the nucleotide specificity of enzyme activation. The activation of cGMP-phosphodiesterase by ACTH-induced cGMP or exogenous cGMP was rapid. In contrast to these observations, there was no activation of cAMP-phosphodiesterase by exogenous cAMP or cGMP. These results indicate that one mechanism by which isolated adrenocortical carcinoma cells regulate the ACTH-induced increase in cGMP is the cyclic nucleotide control of the activity of its phosphodiesterase, thereby regulating cGMP degradation.

Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Adrenal Cortex Neoplasms; Adrenocorticotropic Hormone; Animals; Cyclic AMP; Cyclic GMP; Enzyme Activation; Kinetics; Neoplasms, Experimental; Rats

Topics: Adenylyl Cyclases; Adrenal Cortex Neoplasms; Adrenal Gland Neoplasms; Adrenocorticotropic Hormone; Carcinoma; Cell Line; Corticosterone; Cyclic AMP; Cyclic GMP; Cycloheximide; Dactinomycin; Guanylate Cyclase; Protein Kinases

In the adrenocortical carcinoma cell, in contrast to normal isolated adrenal cells, 10 to 50 muunits of ACTH do not raise the level of adenosine cyclic 3':5'-monophosphate (cyclic AMP), protein kinase activity, and steroidogenesis. This indicates a lesion in the tumor adenylate cyclase system. Two-tenths to 10 mM cyclic AMP and guanosine cyclic 3':5'-monophosphate (cyclic GMP) which stimulate steroidogenesis in a normal cell, activate protein kinase activity in a concentration-response manner without any detectable rise in steroidogenesis in the adrenocortical carcinoma cell. Cycloheximide and actinomycin D do not inhibit the stimulation of the phosphorylation. These results suggest that the tumor cyclic nucleotide-dependent protein kinase activity is unrelated to steroidogenesis and is also not under the transcriptional or translational control steps. Curiously, muM concentrations of cyclic AMP, in contrast to cyclic GMP, stimulate protein kinase activity. In a normal cell, both cyclic AMP and cyclic GMP, in this concentration range, stimulate protein kinase without an increase in steroidogenesis. It is therefore proposed that, in contrast to the normal cell, there is an additional defect in cyclic GMP-dependent protein kinase.

Topics: Adenylyl Cyclases; Adrenal Cortex Hormones; Adrenal Cortex Neoplasms; Adrenal Gland Neoplasms; Adrenal Glands; Adrenocorticotropic Hormone; Animals; Corticosterone; Cyclic AMP; Cyclic GMP; Cycloheximide; Dactinomycin; Enzyme Activation; In Vitro Techniques; Neoplasms, Experimental; Oxidative Phosphorylation; Protein Kinases; Rats

Protein kinase activity has been studied in four human adrenocortical tumors and compared to the one of the normal human adrenal. In two cases where the lack of action of ACTH was related to an anomaly of ACTH receptor, the protein kinase activity was normal. In the other two cases the ACTH receptor was normal, but the protein kinase activity was different from that of the normal adrenal. In one of these cases where the steroidogenesis response of isolated tumor cells to ACTH and DcAMP was higher than in normal adrenal, basal and cAMP stimulated protein kinase activities were significantly higher than those of the normal adrenal, but the activation constants of both nucleotides were similar to those of the normal gland. In the other case, the basal and the cAMP stimulated protein kinase activities were significantly lower, as well as the activation constant of cAMP. However, the binding affinity of 3H-cAMP was normal. Normal adrenal cytosol contains three protein kinases, as resolved by DEAE-cellulose, two of which designated I and II, are cAMP-dependent. The DEAE-cellulose chromatography of the last tumor showed a loss of isoenzyme II. In addition, the protein kinase eluted at the same molarity as that of isoenzyme I of the normal adrenal was not activated by cAMP. Therefore, the lack of response to ACTH of some adrenocortical human tumors may be attributed either to an anomaly of the ACTH receptor or to some defect of the cAMP-dependent protein kinase.

Topics: Adrenal Cortex Neoplasms; Adrenal Gland Neoplasms; Cyclic AMP; Cyclic GMP; Enzyme Activation; Female; Humans; Kinetics; Protamine Kinase; Protamines; Protein Kinases