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S R Bornstein

Publications and source records attributed to S R Bornstein.

At least 91 records · Page 5Linked to original sources
PubMed1999

Detection of Ob-receptor in human adrenal neoplasms and effect of leptin on adrenal cell proliferation.

Leptin, a hormone mainly secreted from adipose tissue, communicates a metabolic signal to the adrenal gland. Ob-Receptor (Ob-R) expression was reported in rat, mice and human adrenal glands. This study intended to investigate possible differences in the Ob-R expression and distribution of Ob-R protein in human adrenal tumors as compared to normal adrenal tissue. Proliferative effects of leptin were analyzed in the human adrenocortical carcinoma cell line (NCI-H295). The full length Ob-R mRNA and the isoforms B219.1 and B219.3 could be demonstrated by RT-PCR in all adrenal tumors (n=8), the tumor cell line (NCI-H295) and normal tissue. In contrast the Ob-R isoform B219.2 was absent in the carcinoma cell line and in most of the adrenal tumors (n=5), whereas it was present in normal adrenals. The Ob-R protein could be demonstrated in benign and malignant adrenocortical tumors. Pheochromocytomas showed only a weak immunostaining with the human Ob-R antibody. Human leptin did not affect the proliferation or variability of adrenal tumor cells as demonstrated by [3H]-thymidine assay and WST-1 test. In conclusion, although functional leptin receptors are expressed in human adrenal tumors, leptin does not regulate tumor cell proliferation.

Adenoma↗
PubMed1999

Leptin levels are suppressed in primary aldosteronism.

Primary aldosteronism is associated with hypertension secondary to salt and water retention, hypokalemia and impaired insulin secretion with glucose intolerance in some patients. The secretion of leptin, a hormone produced by adipocytes, may be altered by reduced insulin secretion in primary aldosteronism. We measured plasma leptin approximately 3 months before and 3 months after curing of primary aldosteronism in 18 patients (12 male, 6 female, body mass index 29.1+/-4.4, mean +/- SD). Patients were treated by unilateral laparoscopic adrenalectomy to remove an aldosterone-producing adenoma. There was a 46% postoperative increase in plasma leptin concentrations from 6.65+/-0.81 to 9.68+/-1.50 ng/ml (P=0.004), despite a non-significant fall in body mass index. Plasma leptin was noted to increase after adrenalectomy in 16 of the 18 patients. The patients also had improved blood pressure and a significant increase in plasma potassium post-operatively. It is proposed that increased insulin secretory capacity associated with correction of negative potassium balance may account for the increase in plasma leptin after curing primary aldosteronism. Further studies are indicated to identify the mechanism of plasma leptin suppression in primary aldosteronism.

Adult↗
PubMed1999

Leptin and its receptor in normal human gastric mucosa and in Helicobacter pylori-associated gastritis.

BACKGROUND: Leptin, a newly discovered weight-reducing hormone, is mainly produced in fat cells. Recently, this hormone has been reported to be produced in rat gastric mucosa cells. In the present study we analyzed the localization and expression of leptin and its receptors in normal human gastric mucosa and in patients with Helicobacter pylori-associated gastritis. METHODS: Plasma leptin levels and gastric mucosa leptin content were determined in 39 patients with dyspepsia. Cellular localization of leptin and of the signaling receptor (Ob-RL) were assessed by immunohistochemistry. Reverse transcriptase polymerase chain reaction (RT-PCR) for leptin receptor isoforms was performed on gastric epithelial cells isolated by laser-capture-microdissection. RESULTS: Leptin content of the corpus gastric mucosa in H. pylori-positive patients was significantly increased (4.6+/-1.2. n = 15) as compared with the H. pylori-negative group (27.5+/-0.5 pg/mg, n = 24, P = 0.006). The presence of leptin immunoreactivity was shown in the lower half of corpus epithelial glands. By RT-PCR no leptin mRNA was detectable in human gastric tissue. In contrast, expression of both Ob-R(L) and the leptin receptor isoforms could be detected in gastric epithelial cells. Leptin receptor protein was detected throughout the mucosa. CONCLUSIONS: Leptin itself is stored and secreted but not produced in human gastric mucosa. The functional receptor and all isoforms are present in human gastric mucosa. H. pylori-associated gastritis leads to significant increases in local leptin concentration in the gastric corpus.

Analysis of Variance↗
PubMed1999

Adrenomedullary function is severely impaired in 21-hydroxylase-deficient mice.

Deficiency of 21-hydroxylase (21-OH), one of the most common genetic defects in humans, causes low glucocorticoid and mineralocorticoid production by the adrenal cortex, but the effect of this disorder on the adrenomedullary system is unknown. Therefore, we analyzed the development, structure, and function of the adrenal medulla in 21-OH-deficient mice, an animal model resembling human congenital adrenal hyperplasia. Chromaffin cells of 21-OH-deficient mice exhibited ultrastructural features of neuronal transdifferentiation with reduced granules, increased rough endoplasmic reticulum and small neurite outgrowth. Migration of chromaffin cells in the adrenal to form a central medulla was impaired. Expression of phenylethanolamine-N-methyltransferase (PNMT) was reduced to 27 +/- 9% (P<0.05), as determined by quantitative TaqMan polymerase chain reaction, and there was a significant reduction of cells staining positive for PNMT in the adrenal medulla of the 21-OH-deficient mice. Adrenal contents of epinephrine were decreased to 30 +/- 2% (P<0. 01) whereas norepinephrine and dopamine levels were reduced to 57 +/- 4% (P<0.01) and 50 +/- 9% (P<0.05), respectively. 21-OH-deficient mice demonstrate severe adrenomedullary dysfunction, with alterations in chromaffin cell migration, development, structure, and catecholamine synthesis. This hitherto unrecognized mechanism may contribute to the frequent clinical, mental, and therapeutic problems encountered in humans with this genetic disease.

Adrenal Hyperplasia, Congenital↗
PubMed1999

Demonstration of a probenecid-inhibitable anion exchanger involved in the release of cortisol and cAMP and in the uptake of p-aminohippurate in bovine adrenocortical cells.

Recently we provided evidence for the involvement of a probenecid-inhibitable anion exchanger in cortisol release from primary cultures of bovine adrenocortical cells. In the present study, we further characterized this exchange transporter. Adrenocorticotropic hormone stimulated 3H-p-aminohippurate (3H-PAH) uptake into as well as cortisol release from the cells about two- and tenfold, respectively. Probenecid inhibited both 3H-PAH uptake and cortisol release by about 55 and 63%. Preincubation of the cells with 1 mM PAH trans-stimulated 3H-PAH uptake by 30%, whereas cortisol release was inhibited by 30%. 3H-PAH uptake was cis-inhibited by 1 mM glutarate or by 1 mM cortisol in the medium, while cortisol release was trans-stimulated by glutarate. PAH in the incubation medium showed saturable cis-inhibition of 3H-PAH uptake. The release of cyclic adenosine monophosphate, a substrate of the renal PAH exchanger, was also inhibited by probenecid and trans-stimulated by glutarate. In summary, the trans-stimulation and cis-inhibition experiments support the concept of an anion exchanger involved in cortisol and cyclic adenosine monophosphate release from and PAH uptake into adrenocortical cells.

Adrenal Cortex↗
PubMed1999

Local renin-angiotensin system is involved in K+-induced aldosterone secretion from human adrenocortical NCI-H295 cells.

NCI-H295, a human adrenocarcinoma cell line, has been proposed as a model system to define the role of the renin-angiotensin system in the regulation of aldosterone production in humans. Because the precise cellular localization of the components of the renin-angiotensin system in human adrenal cortical cells remains unclear, we investigated their localization in this defined cell system. NCI-H295 cells expressed both angiotensinogen and renin as shown by reverse transcriptase polymerase chain reaction and immunohistochemistry. Human angiotensin-converting enzyme (ACE) was not detectable by immunocytochemistry, ACE binding, or reverse transcriptase polymerase chain reaction. However, 3.5 mmol/L K+ stimulated the formation of both angiotensin I and angiotensin II 1. 9- and 2.5-fold, respectively, and increased aldosterone release 3. 0-fold. The K+-induced stimulation of aldosterone release was decreased by captopril and enalaprilat (24% and 26%, respectively) and by the angiotensin type 1 (AT1)-receptor antagonist losartan (28%). Angiotensin II-induced stimulation of aldosterone release was abolished by losartan treatment. Specific [125I]Sar1-angiotensin II binding was detected by receptor autoradiography. The binding of [125I]Sar1-angiotensin II was completely displaced by the AT1 antagonist losartan but not by the AT2 receptor ligand PD 123319, confirming the expression of angiotensin II AT1 receptors in NCI-H295 cells. Our results demonstrate that NCI-H295 cells express most of the components of the renin-angiotensin system. Our failure to detect ACE, however, suggests that the production of angiotensin II in NCI-H295 cells may be ACE independent. NCI-H295 cells are able to produce angiotensin II, and K+ increases aldosterone secretion in part through an angiotensin-mediated pathway. The production of angiotensin II in NCI-H295 cells demonstrates that this human cell line can be useful to characterize the role of locally produced angiotensin II in the regulation of aldosterone release.

Adrenal Cortex↗
PubMed1999

Prenatal dexamethasone treatment does not prevent alterations of the hypothalamic pituitary adrenal axis in steroid 21-hydroxylase deficient mice.

A major difficulty in the clinical management of congenital adrenal hyperplasia (CAH) is adjustment of glucocorticoid doses to suppress ACTH and androgens without causing iatrogenic hypercortisolism. The possibility that structural alterations of the adrenal or a dysfunction of the hypothalamic pituitary adrenal (HPA) axis caused by glucocorticoid deficiency during fetal life contribute to this problem was studied in 21-hydroxylase deficient mice caused by deletion of the cytochrome P-450 21-hydroxylase gene. Homozygotes showed about 200-fold elevations in plasma progesterone, hyperplastic adrenal cortices lacking zonation, and structural alterations of adrenocortical mitochondria. Histochemical studies showed increases in hypothalamic CRH messenger RNA (mRNA) and immunoreactive (ir) CRH, and pituitary POMC mRNA in homozygous mice. VP mRNA levels in PVN perikarya were normal, but irVP in parvicellular terminals of the median eminence was increased in homozygotes. Prenatal dexamethasone treatment (0.5 to 2 microg/day) prevented the increases in CRH mRNA, whereas dexamethasone only partially decreased POMC mRNA levels, and had no effect on serum progesterone levels. The data suggest that intrauterine glucocorticoid deficiency in CAH causes hyperactivity of the hypothalamic-pituitary-corticotroph axis and insensitivity to glucocorticoid feedback. These studies in 21-hydroxylase deficient mice may provide new insights on the mechanism, clinical manifestations and management of some types of human CAH.

Adrenal Glands↗
PubMed1999

Lymphocytes stimulate dehydroepiandrosterone production through direct cellular contact with adrenal zona reticularis cells: a novel mechanism of immune-endocrine interaction.

Adrenal androgen production was reduced by 80% in patients receiving T lymphocyte-suppressive medications compared to that in age-matched controls. In vitro, however, neither tacrolimus nor cyclosporin A reduced dehydroepiandrosterone (DHEA) release by adrenocortical cells. Therefore, we examined the potential role of lymphocytes in adrenal androgen production, using cocultures of human T lymphocytes and adrenocortical primary or transformed cells. Co-cultures led to a 4-fold elevation of DHEA levels (490.4 +/- 94.8% over basal), which was greater than the increase observed after the addition of maximal concentrations of ACTH (117.4 +/- 14.8%). Separation of cells by semipermeable membranes abolished this effect, and transfer of leukocyte-conditioned medium had little androgen-stimulating effect. These data suggested that the observed stimulation of androgen secretion required cell contact rather than soluble paracrine factor(s). Furthermore, we examined human adrenal glands for the presence of T lymphocytes and contact between these cells and steroid-secreting cells of the zona reticularis. Indeed, T lymphocytes expressing CD4 and CD8 antigens were present within human adrenal zona reticularis by immunohistochemical subtyping. Electron microscopic analyses demonstrated direct cell-cell contact between T lymphocytes and adrenocortical cells in situ. This study provides evidence for a novel mechanism of immune-endocrine interactions of direct T lymphocyte-adrenocortical cell contact-mediated stimulation of adrenal androgen secretion.

Adrenocorticotropic Hormone↗
PubMed1999

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.

Adolescent↗
PubMed1998

[Progress in molecular medicine: "laser capture microdissection"].

BACKGROUND: With the unravelling of the human genome, we now face the challenge of defining the function and clinical relevance of single genes. To do this, we should be able to isolate normal and diseased cells from complex tissue structures to make them accessible to sensitive molecular analyses. Laser Capture Microdissection (LCM) was developed to meet this challenge. METHOD AND APPLICATION: LCM allows the precise dissection of cells with the help of a laser beam under direct visualization in the microscope, and the sterile transfer of these cells into a DNA or RNA isolation buffer. The technique is ideal for investigating cell-cell interactions, for performing mutation analyses, and for the production of high-quality cDNA libraries. Expression studies of known and unknown genes are currently employed successfully to define tissue- and simple cell-specific patterns which help elucidate the etiology and pathogenesis of colon, lung, breast, prostate, adrenal, ovary, and other organ tumors. The LCM system developed at the NIH is, therefore, an important part of the Cancer-Genome Anatomy Project (CGAP), which sequences and publishes the structures of genes that are expressed in human tumors. In combination with the modern cDNA arrays, it will thus be possible to analyze the expression of several thousands of genes in one step and to develop individual therapeutic strategies in the not too distant future. CONCLUSIONS: The LCM is a major advance in molecular medicine, enabling us to combine highly-sensitive gene analysis techniques with conventional histologic and morphologic methods. Applications range from research to diagnosis, and to monitoring disease progression.

Cell Separation↗
PubMed1998

Tissue remodelling in the adrenal gland.

Adaptation of the adrenal gland to the demands of the organism is regulated functionally and structurally. Three common hypotheses on zonation in the adrenal gland, the migrational, zonal, and transformation field theories, try independently to reconcile the findings on structure, proliferation, and cell death. The classical theories on zonation are revisited in the light of recent data on cell death and renewal. In accordance with data on cell death as immunoreactivity against FAS(CD 95), an apoptosis-inducing receptor, in situ end labelling of fragmented DNA, and ultrastructural analyses, programmed cell death (PCD) occurs throughout the whole organ. The angiotensin II receptor subtypes described in the adrenal allow an additional regulation of tissue homeostasis by proliferative and even by the antiproliferative effects of the angiotensin II type 2 receptor. Proto-oncogenes are involved in the regulation of cell cycle and PCD, and adrenocorticotropin asserts its tissue integrating and differentiating effects by regulating proto-oncogenes such as c-jun, c-fos, jun-B and c-myc. Polypeptides involved in proliferation and DNA repair, such as proliferating cell nuclear antigen and Ki-67, have been found within zones of expected cell senescence. The expression of the class II major histocompatibility complex on normal adrenocortical cells allows cell-to-cell communication with the immune system and may trigger the Fas/Fas-ligand system to permit tissue regression and decreasing activity in both systems. In summary, new data allow us to reappraise and to reconcile the classical theories. Apoptosis is a physiological process in the adrenal gland. There is a differential regulation of apoptosis in the different zones. An investigation of this process may elucidate the basic mechanisms of adrenal zonation.

Adrenal Glands↗
PubMed1998

Human adrenocortical NCI-H295 cells express VIP receptors. Steroidogenic effect of vasoactive intestinal peptide (VIP).

VIP receptors are frequently overexpressed by various endocrine tumors. In this study the expression of VIP receptors in the human adrenocortical carcinoma cell line NCI-H295 and their involvement in the regulation of steroidogenesis was investigated. NCI-H295 cells express VIP1 and VIP2 receptors as demonstrated by RT-PCR, whereas they do not express VIP itself. The receptors are functionally coupled to steroidogenesis since VIP (10(-9) M to 10(-6) M) exerted a dose-dependent stimulatory effect on the release of aldosterone, cortisol, and DHEA. VIP increased ACTH-stimulated releases of aldosterone and cortisol. The proliferation rate of NCI-H295 cells was not affected by VIP. These data show that NCI-H295 cells express both forms of the VIP receptor and that VIP is involved in an ACTH-independent regulation of steroidogenesis in the adrenal tumor cells.

Adrenal Cortex↗