A Gene-Based Classification of Primary Adrenocortical Hyperplasias.

Primary or adrenocorticotropin-independent adrenocortical tumors and hyperplasias represent a heterogeneous group of adrenocortical neoplasms that arise from various genetic defects, either in isolation or familial. The traditional classification as adenomas, hyperplasias, and carcinomas is non-specific. The recent identification of various germline and somatic genes in the development of primary adrenocortical hyperplasias has provided important new insights into the molecular pathogenesis of adrenal diseases. In this new era of personalized care and genetics, a gene-based classification that is more specific is required to assist in the understanding of their disease processes, hormonal functionality and signaling pathways. Additionally, a gene-based classification carries implications for treatment, genetic counseling and screening of asymptomatic family members. In this review, we discuss the genetics of benign adrenocorticotropin-independent adrenocortical hyperplasias, and propose a new gene-based classification system and diagnostic algorithm that may aid the clinician in prioritizing genetic testing, screening and counseling of affected, at risk individuals and their relatives.

mTOR pathway is activated by PKA in adrenocortical cells and participates in vivo to apoptosis resistance in primary pigmented nodular adrenocortical disease (PPNAD).

Primary pigmented nodular adrenocortical disease (PPNAD) is associated with inactivating mutations of the PRKAR1A tumor suppressor gene that encodes the regulatory subunit R1α of the cAMP-dependent protein kinase (PKA). In human and mouse adrenocortical cells, these mutations lead to increased PKA activity, which results in increased resistance to apoptosis that contributes to the tumorigenic process. We used in vitro and in vivo models to investigate the possibility of a crosstalk between PKA and mammalian target of rapamycin (mTOR) pathways in adrenocortical cells and its possible involvement in apoptosis resistance. Impact of PKA signaling on activation of the mTOR pathway and apoptosis was measured in a mouse model of PPNAD (AdKO mice), in human and mouse adrenocortical cell lines in response to pharmacological inhibitors and in PPNAD tissues by immunohistochemistry. AdKO mice showed increased mTOR complex 1 (mTORC1) pathway activity. Inhibition of mTORC1 by rapamycin restored sensitivity of adrenocortical cells to apoptosis in AdKO but not in wild-type mice. In both cell lines and mouse adrenals, rapid phosphorylation of mTORC1 targets including BAD proapoptotic protein was observed in response to PKA activation. Accordingly, BAD hyperphosphorylation, which inhibits its proapoptotic activity, was increased in both AdKO mouse adrenals and human PPNAD tissues. In conclusion, mTORC1 pathway is activated by PKA signaling in human and mouse adrenocortical cells, leading to increased cell survival, which is correlated with BAD hyperphosphorylation. These alterations could be causative of tumor formation.

Moving toward personalized cell-based interventions for adrenal cortical disorders: part 1--Adrenal development and function, and roles of transcription factors and signaling proteins.

Transdifferentiation of an individual's own cells into functional differentiated cells to replace an organ's lost function would be a personalized approach to therapeutics. In this two part series, we will describe the progress toward establishing functional transdifferentiated adrenal cortical cells. In this article (Part 1), we describe adrenal development and function, and discuss genes involved in these processess and selected for use in our pilot studies of transdifferentiation that are presented in the second article (Part 2).

New genes and/or molecular pathways associated with adrenal hyperplasias and related adrenocortical tumors.

Over the course of the last 10 years, we have studied the genetic and molecular mechanisms leading to disorders that affect the adrenal cortex, with emphasis on those that are developmental, hereditary and associated with adrenal hypoplasia or hyperplasia, multiple tumors and abnormalities in other endocrine glands. On the basis of this work, we propose an hypothesis on how adrenocortical tumors form and the importance of the cyclic AMP-dependent signaling pathway in this process. The regulatory subunit type 1-alpha (RIalpha) of protein kinase A (PKA) (the PRKAR1A gene) is mutated in most patients with Carney complex and primary pigmented nodular adrenocortical disease (PPNAD). Phosphodiesterase-11A (the PDE11A gene) and -8B (the PDE8B gene) mutations were found in patients with isolated adrenal hyperplasia and Cushing syndrome, as well in patients with PPNAD. PKA effects on tumor suppression and/or development and the cell cycle are becoming clear: PKA and/or cAMP act as a coordinator of growth and proliferation in the adrenal cortex. Mouse models in which the respective genes have been knocked out see m to support this notion. Genome-wide searches for other genes responsible for adrenal tumors and related diseases are ongoing; recent evidece of the involvement of the mitochondrial oxidation pathway in adrenocortical tumorigenesis is derived from our study of rare associations such as those of disorders predisposing to adrenomedullary and related tumors (Carney triad, the dyad of paragangliomas and gastric stromal sarcomas or Carney-Stratakis syndrome, hereditary leiomyomatosis and renal cancer syndrome) which appear to be associated with adrenocortical lesions.

Heritable forms of hypertension.

Among the causes of secondary hypertension are a group of disorders with a Mendelian inheritance pattern. Recent advances in molecular biology have unveiled the pathogenesis of hypertension in many of these conditions. Remarkably, the mechanism in every case has proved to be upregulation of sodium (Na) reabsorption in the distal nephron, with accompanying expansion of extracellular volume. In one group, the mutations involve the Na-transport machinery in distal tubule cells themselves: the distal convoluted tubule (DCT) cell and the principal cell of the collecting duct. Examples include Liddle's syndrome, with an activating mutation of epithelial Na channel (ENaC); two types of Gordon's syndrome, with mutations in two regulatory kinases [with no lysine (K) serine/threonine protein kinases (WNK)1 or WNK4]; and apparent mineralocorticoid excess (AME), with an inactivating mutation in the glucocorticoid-metabolizing 11beta-hydroxysteroid dehydrogenase type 2 enzyme (11HD2). In another group, abnormal adrenal steroid production leads to inappropriate stimulation of the mineralocorticoid receptor (MR) in the distal nephron. The pathophysiology may involve inappropriate production of aldosterone [in glucocorticoid-remediable aldosteronism (GRA) and familial hyperaldosteronism type II (FH II)], of cortisol (in familial glucocorticoid resistance), or of other steroid metabolites (in congenital adrenal hyperplasia and GRA). In contrast to earlier beliefs, hypertension in many of the inherited disorders may be mild, and electrolyte and acid-base abnormalities are often not present. Monogenic hypertension should therefore enter the differential diagnosis of any child or adolescent with hypertension. Plasma renin activity (PRA) is the appropriate screening tool for all types of inherited hypertension.

Long-Term Outcome of Primary Bilateral Macronodular Adrenocortical Hyperplasia After Unilateral Adrenalectomy.

CONTEXT: Unilateral adrenalectomy has been proposed in selected patients with primary bilateral macronodular adrenocortical hyperplasia (PBMAH), but its long-term outcome is unclear. OBJECTIVE: The aim of this study was to analyze long-term clinical and biochemical outcomes of unilateral adrenalectomy vs bilateral adrenalectomy in patients with PBMAH in comparison with the outcome of cortisol-producing adenoma (CPA) treated with unilateral adrenalectomy. DESIGN: Retrospective observational study in three German and one Italian academic tertiary care center. PATIENTS AND METHODS: Twenty-five patients with PBMAH after unilateral adrenalectomy (unilat-ADX-PBMAH), nine patients with PBMAH and bilateral adrenalectomy (bilat-ADX-PBMAH), and 39 patients with CPA and unilateral adrenalectomy (unilat-ADX-CPA) were included. RESULTS: Baseline clinical and biochemical parameters were comparable in patients with unilat-ADX-PBMAH, bilat-ADX-PBMAH, and unilat-ADX-CPA. Directly after surgery, 84% of the patients with unilat-ADX-PBMAH experienced initial remission of Cushing syndrome (CS). In contrast, at last follow-up (median, 50 months), 32% of the patients with unilat-ADX-PBMAH were biochemically controlled compared with nearly all patients in the other two groups (P = 0.000). Adrenalectomy of the contralateral side had to be performed in 12% of the initial patients with unilat-ADX-PBMAH. Three of 20 patients with unilat-ADX-PBMAH (15%) died during follow-up, presumably of CS-related causes; no deaths occurred in the other two groups (P = 0.008). Deaths occurred exclusively in patients who were not biochemically controlled after unilateral ADX. CONCLUSIONS: Our data suggest that unilateral adrenalectomy of patients with PBMAH leads to clinical remission and a lower incidence of adrenal crisis but in less sufficient biochemical control of hypercortisolism, potentially leading to higher mortality.

Expression of progesterone and estradiol receptors in normal adrenal cortex, adrenocortical tumors, and primary pigmented nodular adrenocortical disease.

Adrenal tumors occur more frequently in women and are the leading cause of Cushing's syndrome during pregnancy. We aimed to evaluate the potential role of sex steroids in the susceptibility of women to adrenocortical tumors. We evaluated the presence of the progesterone receptor (PR), estradiol receptors (ERs), and aromatase in 5 patients with primary pigmented nodular adrenal disease (PPNAD), 15 adrenocortical adenomas (ACAs) and adjacent normal tissues, 12 adrenocortical carcinomas (ACCs), and 3 normal adrenal glands (NA). The expression of PR and ERalpha was evaluated by enzyme immunoassays, real-time RT-PCR, immunohistochemistry, and cytosol-based ligand-binding assays. ERbeta and aromatase levels were evaluated by real-time RT-PCR. ERalpha concentrations were low in NA, in adrenal tissues adjacent to ACA (51+/-33), in ACC (53+/-78), and lower in ACA (11+/-11 fmol/mg DNA). Conversely, PR concentrations were high in NA and adrenal tissues adjacent to ACA, at 307+/-216 fmol/mg DNA, and were even higher in tumors - 726+/-706 fmol/mg DNA in ACA and 1154+/-1586 fmol/mg DNA in ACC - and in isolated PPNAD nodules. Binding study results in four tumors were compatible with binding to a steroid receptor. In patients with PPNAD, a strong positive immunohistochemical signal was associated with the sole isolated nodular regions. ERbeta transcript levels were very high in all samples except those for two ACCs, whereas aromatase levels were low. PR and ERbeta are clearly present in normal adrenal glands and adrenal tumors. Further studies may shed light on the possible pathogenic role of these receptors in adrenal proliferation.

Case report of familial Carney complex due to novel frameshift mutation c.597del C (p.Phe200LeufsX6) in PRKAR1A.

Carney complex is an autosomal dominantly inherited disease characterized by skin pigmentation, myxoma, primary pigmented nodular adrenocortical disease (PPNAD), and acromegaly. However, only a few incidences of PPNAD combined with acromegaly are observed in patients. The type 1alpha regulatory subunit of cAMP-dependent protein kinase (PRKAR1A) has been identified in patients as a causative gene for Carney complex by a positional cloning approach. Here, we report a female patient diagnosed with Cushing's syndrome and a GH-producing pituitary adenoma without otherwise evident acromegaly that could be diagnosed only by specialized endocrinological tests. Based on family history of acromegaly (mother and sister) and the fact that the combination of both diseases is very rare, genetic diagnosis involving Carney complex was considered to be appropriate. The 10 exons and flanking regions of PRKAR1A were screened for mutations by direct DNA sequencing. The patient and her mother and sister were found to have the same, novel frameshift mutation resulting from a single base deletion in exon 6 coding cAMP-binding domain A, denoted c.597delC in PRKAR1A. This single base deletion generated an immature stop codon at the sixth codon (p.Phe200LeufsX6). Even family members with the same mutation can show distinct phenotypes, suggesting that Carney complex is a multifactorial disorder comprising various genetic and environmental factors. Genetic diagnosis makes it possible to prepare more effective therapeutic strategies for patients and gene carriers and to avoid unnecessary tests for non-carriers in the family of the patient.

Opioid endocrinopathy in women consuming prescribed sustained-action opioids for control of nonmalignant pain.

UNLABELLED: Hypogonadotrophic hypogonadism is characteristically induced in men by intrathecal, transdermal, or sustained-action opioids. Although women receiving intrathecal opioids have similar changes, often accompanied by amenorrhea, hypogonadotrophic hypogonadism has not been documented in women receiving sustained-action, transdermal, or oral opioids. Dehydroepiandrosterone sulfate deficiency, indicating adrenal inhibition, is present in most men and women chronically consuming sustained-action oral or transdermal opioids. We recorded menstrual histories and measured gonadotrophin, androgen, and estradiol levels in 47 women ages 30 to 75 years who were consuming sustained-action oral or transdermal opioids for control of nonmalignant pain and in 68 non-opioid-consuming control subjects. Testosterone, estradiol, and dehydroepiandrosterone sulfate values were 48% to 57% lower in opioid-consuming women with intact ovarian tissue than in control subjects (P < .01-.05). Luteinizing hormone and follicle-stimulating hormone values averaged 30% lower in premenopausal and 70% lower in postmenopausal opioid consumers (P < .001). Among oophorectomized women not consuming estrogen, free testosterone levels were 39% lower in opioid consumers (P < .05), indicating impaired adrenal androgen production. Additional lowering of free testosterone levels was associated independently with oral estrogen replacement and low body mass index. Menses had often ceased soon after beginning sustained-action opioid therapy. Our observations document hypogonadotrophic hypogonadism plus decreased adrenal androgen production in most women consuming sustained-action oral or transdermal opioids. PERSPECTIVE: These observations demonstrate profound inhibition of ovarian sex hormone and adrenal androgen production among women chronically consuming sustained-action opioids. Related consequences include altered menstrual flow, probable reduced fertility, and possible contributions to opioid-associated depression, osteoporosis, and hyperalgesia. Measurements of bone density, estradiol, and free testosterone may guide appropriate therapy.

Acute adrenal cortex injury during cardiopulmonary bypass in a canine model.

OBJECTIVE: Cardiopulmonary bypass (CPB) might induce systemic inflammatory responses that cause acute injuries to multiple organs. However, no direct evidence exists to determine whether CPB leads to adrenal cortex injury or to describe its underlying mechanism. METHODS: Twelve healthy adult beagles were randomly assigned into control and CPB groups. After cannulation, mild hypothermia CPB was performed in the CPB group but not in the control group. The serum concentrations of various cytokines, cortisol, and aldosterone were assessed. Adrenal cortex injuries were evaluated using standard histological methods. Steroidogenic enzymes and the nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome pathway were detected using quantitative polymerase chain reaction and Western blot analysis. RESULTS: During CPB, serum interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor α, cortisol, and aldosterone levels were significantly higher in the CPB group. The pathologic study revealed higher injury scores (3.6 ± 0.6 vs 0.7 ± 0.7) and significantly more severe edema, inflammatory cell infiltration (lymphocytes and neutrophils), and apoptosis in the CPB group. The electron microscopic examination showed swollen mitochondria, ruptured mitochondrial cristae, reduced lipid droplets, and increased secondary lysosomes in the CPB group. The mRNA expression levels of NLRP3 and the protein levels of 17α-hydroxylase and IL-1ß in adrenal tissue were significantly upregulated in the CPB group. CONCLUSIONS: CPB induces significant systemic and local inflammation in the adrenal cortex and results in cytological architectural and ultrastructural alterations in adrenocorticocytes. In addition, the NLRP3 inflammasome pathway might promote adrenal gland injury during CPB and might represent a novel potential therapeutic target.

Primary bilateral adrenal nodular disease with Cushing's syndrome: varying aetiology.

Primary adrenal disorders contribute 20%â€"30% of patients with endogenous Cushing's syndrome. Most of the primary adrenal diseases are unilateral and include adenoma and adrenocortical carcinoma, whereas bilateral adrenal lesions are uncommon and include primary pigmented nodular adrenocortical disease, primary bilateral macronodular adrenocortical hyperplasia, isolated micronodular adrenocortical disease, bilateral adenomas or carcinomas, and rarely pituitary adrenocorticotropic hormone-dependent adrenal nodular disease. Cyclic adenosine monophosphate-dependent protein kinase A signalling is the major activator of cortisol secretion in primary adrenal nodular disorders. We report two cases of bilateral adrenal nodular disease with endogenous Cushing's syndrome, including one each of primary pigmented nodular adrenocortical disease and primary bilateral macronodular adrenocortical hyperplasia.

Strategies for the characterization of disorders in cortisol sensitivity.

CONTEXT: The clinical presentation of abnormalities in glucocorticoid (GC) sensitivity is diverse, and therefore it is difficult to diagnose this condition. OBJECTIVE AND DESIGN: The objective of the study was to develop strategies for the characterization of GC sensitivity disorders. SETTING: The study was conducted in an outpatient clinic. PATIENTS: Nine patients with GC sensitivity disorders participated. INTERVENTIONS: Sequence analysis of the GC receptor (GR), determination of GR number per cell, GR ligand-binding affinity, and GR splice regulation were performed in freshly prepared peripheral blood mononuclear lymphocytes and Epstein-Barr virus-transformed lymphoblasts. Cellular GC sensitivity was determined ex vivo by measuring the effect of dexamethasone on GC-induced leucine-zipper and IL-2 mRNA levels and on cell proliferation. RESULTS: Differences in GR number per cell, GR affinity, GR splice variants, and effects on transactivation or transrepression of GC-sensitive genes were observed between patients and controls. Epstein-Barr virus transformation of lymphoblasts had no influence on GR affinity but increased the GR number 5-fold in healthy controls. In patients diagnosed as cortisol resistant, however, GR number after transformation was increased significantly less than 5-fold, whereas a higher GR number was observed in a patient suspected of cortisol hypersensitivity. CONCLUSION: This study illustrates several strategies to define abnormalities in GC sensitivity by describing nine patients with affected GC sensitivity, all with a unique clinical course and background.

PKA regulatory subunit 1A inactivating mutation induces serotonin signaling in primary pigmented nodular adrenal disease.

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent hypercortisolism. The disease is primarily caused by germline mutations of the protein kinase A (PKA) regulatory subunit 1A (PRKAR1A) gene, which induces constitutive activation of PKA in adrenocortical cells. Hypercortisolism is thought to result from PKA hyperactivity, but PPNAD tissues exhibit features of neuroendocrine differentiation, which may lead to stimulation of steroidogenesis by abnormally expressed neurotransmitters. We hypothesized that serotonin (5-HT) may participate in the pathophysiology of PPNAD-associated hypercortisolism. We show that PPNAD tissues overexpress the 5-HT synthesizing enzyme tryptophan hydroxylase type 2 (Tph2) and the serotonin receptors types 4, 6, and 7, leading to formation of an illicit stimulatory serotonergic loop whose pharmacological inhibition in vitro decreases cortisol production. In the human PPNAD cell line CAR47, the PKA inhibitor H-89 decreases 5-HT4 and 5-HT7 receptor expression. Moreover, in the human adrenocortical cell line H295R, inhibition of PRKAR1A expression increases the expression of Tph2 and 5-HT4/6/7 receptors, an effect that is blocked by H-89. These findings show that the serotonergic process observed in PPNAD tissues results from PKA activation by PRKAR1A mutations. They also suggest that Tph inhibitors may represent efficient treatments of hypercortisolism in patients with PPNAD.

Molecular cloning, chromosomal localization of human peripheral-type benzodiazepine receptor and PKA regulatory subunit type 1A (PRKAR1A)-associated protein PAP7, and studies in PRKAR1A mutant cells and tissues.

A mouse protein that interacts with the peripheral-type benzodiazepine receptor (PBR) and cAMP-dependent protein kinase A (PKA) regulatory subunit RIalpha (PRKAR1A), named PBR and PKA-associated protein 7 (PAP7), was identified and shown to be involved in hormone-induced steroid biosynthesis. We report the identification of the human PAP7 gene, its expression pattern, genomic structure, and chromosomal mapping to 1q32-1q41. Human PAP7 is a 60-kDa protein highly homologous to the rodent protein. PAP7 is widely present in human tissues and highly expressed in seminal vesicles, pituitary, thyroid, pancreas, renal cortex, enteric epithelium, muscles, myocardium and in steroidogenic tissues, including the gonads and adrenal cortex. These tissues are also targets of Carney complex (CNC), a multiple neoplasia syndrome caused by germline inactivating PRKAR1A mutations (PRKAR1A-mut) and associated with primary pigmented nodular adrenocortical disease (PPNAD) and increased steroid synthesis. PAP7 and PRKAR1A expression were studied in PPNAD and in lymphoblasts from patients bearing PRKAR1A-mut. Like PRKAR1A, PAP7 was decreased in CNC lymphocytes and PPNAD nodules, but not in the surrounding cortex. These studies showed that, like in the mouse, human PAP7 is highly expressed in steroidogenic tissues, where it follows the pattern of PRKAR1A expression, suggesting that it participates in PRKAR1A-mediated tumorigenesis and hypercortisolism.

Growth hormone receptor messenger ribonucleic acid in normal and pathologic human adrenocortical tissues--an analysis by quantitative polymerase chain reaction technique.

GH receptor (GHR) has been reported to express in both normal rat and human adrenals. However, no study examined GHR expression in diseased human adrenal cortex. We quantitated, with RT-PCR, GHR messenger RNA (mRNA) in both normal and diseased human adrenal cortex with the following results: GHR mRNA levels in four histologically normal, not steroid-stimulated, control adrenal cortices was 1.5-11 x 10(4) molecules/microgram total RNA; in three diffusely hyperplastic adrenals (DH): 6.7-17.7 x 10(4); in two nonfunctioning tumors (NF): 0.84-1.9 x 10(4); in five androgen-producing neoplasms (AP): 4.6-34 x 10(4); and in five glucocorticoid-producing neoplasms (GP): 6.7-87 x 10(4). GHR transcript levels among adrenal cortices, DH, NF, AP, and GP reached statistically significant difference (P < 0.03). The GP group exhibited higher GHR mRNA levels than controls (P < 0.006). NF, as well as GP and AP, tumors had less GHR mRNA than their histologically normal adjacent cortex (P < 0.05). A positive correlation between urinary cortisol and GHR messenger RNA (mRNA) levels from GP and DH was observed (r = 0.93, P < 0.003). Our data suggest that GHR is expressed in both normal and diseased adrenal cortex and that GHR mRNA accumulation is less efficient in adrenocortical neoplasm than their adjacent nonneoplastic cortex. GHR expression in adrenal cortex provides an evidence of direct GH action in this tissue.

Glucocorticoid receptor abnormalities in fibroblasts from patients with idiopathic resistance to dexamethasone diagnosed when evaluated for adrenocortical disorders.

A retrospective survey was accomplished on 420 consecutive patients who had undergone dexamethasone suppression tests between 1975-1988 due to suspected adrenal disorders. We found 7 patients in whom glucocorticoid resistance was apparent. They showed 4-6 abnormalities of the 7 investigations used: insensitivity to dexamethasone inhibition (n = 7), increased urinary cortisol (n = 3), glucocorticoid receptor (GR) thermolability (n = 4), decreased number of glucocorticoid receptors (n = 4), abnormal ligand affinity of GR (n = 4), abnormal basal GR mRNA expression (n = 4), and abnormal down-regulation of basal GR mRNA levels by dexamethasone (n = 1). The four patients with GR thermolability also showed increased basal GR mRNA levels. In the other patients the number of GR per cell was decreased without an up-regulation of GR mRNA. It is concluded that the syndromes of glucocorticoid resistance vary notably, clinically as well as biochemically; in patients evaluated for adrenocortical disorders the syndrome is apparently encountered in 1-2% of the patients.

Synaptophysin immunoreactivity in primary pigmented nodular adrenocortical disease: neuroendocrine properties of tumors associated with Carney complex.

Carney complex (CNC) is characterized by lentiginosis and myxomatosis together with a variety of endocrine, neural crest-derived, and other tumors, including primary pigmented nodular adrenocortical disease (PPNAD). PPNAD is characterized by lipofuscin-containing, autonomously functioning, cortisol-producing nodules surrounded by mostly atrophic adrenocortical and normal adrenomedullary tissue. The nature and origin of the tumors, including the myxomas and PPNAD, are unclear. In this study, seven paraffin-embedded PPNAD tumors, one skin myxoma, and two cell lines (one myxoma and one PPNAD) established from patients with CNC were stained with antisera for synaptophysin (SYN), neuron-specific enolase, chromogranin A, tyrosine hydroxylase, and the neural cell adhesion molecule (NCAM). In addition, one PPNAD specimen and one myxoma were analyzed by electron microscopy. The results showed that chromogranin A and tyrosine hydroxylase stained adrenomedullary tissue, but not the PPNAD nodules or the extranodular adrenal cortex. SYN, neuron-specific enolase, and NCAM also stained the medulla. PPNAD nodules and the PPNAD cell line, but not the extranodular adrenal cortex, stained intensely for SYN. The myxoma cell line, but not normal fibroblasts, stained for SYN and NCAM. Ultrastructural analysis of a PPNAD tumor and a skin myxoma revealed a well developed rough endoplasmic reticulum, prominent mitochondria, and vesicle-like structures dispersed throughout the cytoplasm. We conclude that immunostaining for SYN, a marker protein for neuroendocrine cells, clearly distinguishes PPNAD nodules from surrounding adrenocortical tissue and can be helpful in the detection of small nodules in apparently unaffected cortex. The cells of a cutaneous myxoma were also stained positive by two of the three neuroendocrine markers. Finally, both PPNAD and myxoma cells demonstrated ultrastructural features suggestive of neuroendocrine properties. These results support the previously suggested hypothesis that the genetic mechanism leading to CNC involves genes with a neuroendocrine role.

Renal inactivation, mineralocorticoid generation, and 11beta-hydroxysteroid dehydrogenase inhibition ameliorate the antimineralocorticoid effect of progesterone in vivo.

Progesterone (P) is a strong mineralocorticoid receptor (MR) antagonist in vitro. The high P concentrations seen in normal pregnancy only moderately increase renin and aldosterone concentrations. In previous in vitro studies we hypothesized that this may be explained by intrarenal conversion of P to less potent metabolites. To investigate the in vivo anti-MR potency of P, we performed an infusion study in patients with adrenal insufficiency (n = 8). They omitted 9alpha-fluorocortisol for 4 d and hydrocortisone for 0.5 d before a continuous iv infusion of aldosterone for 8.5 h, with an additional iv P infusion commenced at 4 h. During aldosterone infusions the initially elevated urinary sodium to potassium ratio decreased significantly. Despite the 1000-fold excess of P over aldosterone, the urinary sodium to potassium ratio and urinary sodium excretion increased only slightly after 3 h of P infusion. We detected inhibition of renal 11beta-hydroxysteroid dehydrogenase type 2 by P, thus giving cortisol/prednisolone access to the MR. Urinary and plasma concentrations of 17alpha-hydroxyprogesterone, a major metabolite of renal P metabolism, and those of serum androstenedione and deoxycorticosterone, a mineralocorticoid itself, increased significantly during P infusion. This supports the hypothesis of an effective protection of the MR from P by efficient extraadrenal downstream conversion of P.

Plasma cortisol response to thyrotrophin releasing hormone and luteinizing hormone releasing hormone in healthy kennel dogs and in dogs with pituitary-dependent hyperadrenocorticism.

The change in the plasma concentration of cortisol after the administration of thyrotrophin releasing hormone (TRH) and LH releasing hormone (LH-RH) was studied in normal dogs and in dogs with pituitary-dependent hyperadrenocorticism (PDH). The normal dogs showed a small but significant increase in the plasma concentration of cortisol 15 min after intravenous injection of TRH and LH-RH. In ten of the dogs with PDH the response to TRH was not significantly different from that in the normal dogs, but in 13 the response was significantly greater. In 15 of the dogs with PDH the response to LH-RH administration was within or below the range of responses in the normal dogs and in only one dogs was the response to LH-RH greater than that in the normal dogs. These findings are discussed in relation to the pathogenesis of PDH.