Whole-body autoradiographic study of [3H]-PK 11195 distribution in dunning AT-1 tumour-bearing rats

In vivo binding of [3H]-PK 11195 to peripheral benzodiazepine binding sites in Dunning AT-1 prostatic tumour-bearing rats was investigated by whole-body autoradiography. Distribution and retention of PK 11195 in tumour and other organs was examined at different time intervals. Autoradiograms indicated PK 11195 binding sites in the periphery of the tumour, whereas no or little binding was detected in the prostate. Among other organs, adrenal cortex was most intensely radiolabelled. Administration of nonradioactive PK 11195 before [3H]-PK 11195 blocked binding in all organs more completely than in tumour, kidney, and adrenal cortex, where low levels of radioactivity still were present. Radioactivity in the tumour, contrary to other organs, seemed to increase with time, indicating a slow uptake with large capacity. High performance liquid chromatography analysis of extracted radioactivity from the tumour showed that almost all radioactivity consisted of intact [3H]-PK 11195. These results indicate binding in vivo of PK 11195 to peripheral benzodiazepine receptors in Dunning AT-1 rat prostatic tumours and a large capacity for uptake and retention of [3H]-PK 11195 in tumours.     

Transforming growth factor alpha, epidermal growth factor, and epidermal growth factor receptor expression in normal and diseased human adrenal cortex by immunohistochemistry and in situ hybridization

Because epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and epidermal growth factor receptor (EGFR) have been implicated in the regulation of adrenocortical function, we used immunohistochemistry and in situ hybridization of EGF and TGF-alpha to study 41 specimens of human adrenal cortex, including 10 normal specimens, 15 aldosteronomas, five Cushing's adenomas, six adrenocortical incidentalomas, and five carcinomas to determine what role these growth factors play in controlling human adrenocortical function. Neither immunoreactivity nor mRNA hybridization signals to EGF was detected in any specimens, and EGF therefore may exert its effects on adrenal function as an endocrine hormone. TGF-alpha expression was detected at both protein and mRNA levels in normal and neoplastic adrenal cortex, demonstrating that TGF-alpha is synthesized locally in human adrenal cortex. TGF-alpha expression was observed in the cells with increased steroidogenesis, including compact tumor cells and zona fasciculata cells with lipid depletion, but did not necessarily correlate with production sites of any specific steroid hormone. EGFR immunoreactivity was more widely distributed than TGF-alpha immunoreactivity. Both TGF-alpha and EGFR expression were markedly elevated in adrenocortical carcinomas. TGF-alpha and EGFR thus appear to be involved in biological function in both normal and neoplastic human adrenal cortex. In addition, TGF-alpha and EGFR may play important roles in some biological features of adrenocortical malignancy.     

Differential expression of prolactin receptor (PRLR) in normal and tumorous adrenal tissues: separation of cellular endocrine compartments by laser capture microdissection (LCM)

PRL stimulates adrenal steroidogenesis. In this study, we compared the PRLR expression in normal and tumorous adrenal tissues and investigated a potential proliferative effect of PRL in adrenal cells. mRNA expression of long and intermediate forms of PRLR was detected in both normal adrenal cortex as well as benign and malignant adrenal tumors and in the human adrenocortical carcinoma cell line NCI-H295. Molecular analysis of cells procured by LCM clearly demonstrated that PRLR mRNA is expressed in the adrenal cortex but not in the medulla. Immunostaining revealed PRLR protein in all three zones of the normal adrenal cortex. Furthermore, adrenal carcinomas and adenomas stained positive for the PRLR, while in phaeochromocytomas as in the normal adrenal medulla, no specific staining was observed. By WST-1 test, we could show that PRL (10(-7) M) decreased proliferation and viability of adrenal cells in primary cell culture suggesting that PRL is not a mitogenic factor of adrenocortical cells.     

In vitro and in vivo primate evaluation of carbon-11-etomidate and carbon-11-metomidate as potential tracers for PET imaging of the adrenal cortex and its tumors

METHODS: With the purpose of developing a PET imaging agent for tumors of the adrenal cortex, we developed syntheses for 11C-etomidate and its methyl analog, 11C-metomidate. (R)-[O-ethyl-1-11C]Etomidate and (R)-[O-methyl-11C]metomidate were prepared by reaction of the appropriate respective 11C-labeled alkyl iodide and the tetrabutylammonium salt of the carboxylic acid derivative. The specificity of binding to the adrenal cortex was tested through the use of frozen section autoradiography of different tissues of the rat, pig and human. Inhibition of tracer binding was evaluated with etomidate, ketoconazole and metyrapone, well-known inhibitors of enzymes for steroid synthesis. Tracer binding to different human tumor samples was compared to immunohistochemical staining with antibodies for the steroid synthesis enzymes P450 11beta (11beta-hydroxylase), P450 scc (cholesterol side-chain cleavage enzyme), P450 C21 (21 -hydroxylase) and P450 17alpha (17alpha-hydroxylase). Three PET investigations, one with 11C-etomidate and two with 11C-metomidate, were performed in rhesus monkey sections, including the adrenals, liver and kidneys. Time-activity curves were generated from measured tracer uptake in these organs. RESULTS: In frozen section autoradiography of various tissues, high binding was seen in the adrenal cortex from all species, as well as in the tumors of adrenal cortical origin. The level of liver binding was about 50% of that in the adrenals, whereas that of all other organs was <10% of the adrenal binding. The adrenal binding was blocked by etomidate and ketoconazole at low doses but not by metyrapone. The binding in the adrenal tumor samples correlated with immunostaining for P450 11beta . PET studies in the monkey demonstrated high uptake in the adrenals with excellent visualization. The uptake increased with time without indication of washout. Slightly lower uptake was seen in the liver as compared to the adrenals, and in the late images, no organs other than adrenals and liver were seen. CONCLUSION: These investigations indicate that 11C-etomidate and 11C-metomidate have the potential to be useful specific agents for the visualization of the normal adrenal cortex and to provide positive identification of adrenal cortical tumors.     

Localization and differential expression of adenylyl cyclase messenger ribonucleic acids in rat adrenal gland determined by in situ hybridization

The expression of adenylyl cyclases (ACs) in the adult rat adrenal gland was examined. In situ hybridization revealed specific patterns of AC messenger RNA (mRNA) distribution. AC1 was limited exclusively to the adrenal medulla. AC5 and AC6 were mainly expressed in the adrenal medulla, with a weak expression in the zona glomerulosa. AC9 was found in all the three regions of the adrenal cortex but not in the adrenal medulla. All these ACs were detected on postnatal day 1 (PN1), and their pattern of expression was unchanged on PN7, PN21, and PN90 (adult). We analyzed the response of these ACs to various physiological conditions known to affect the synthesis of aldosterone and corticosterone in the adrenal cortex. Our study demonstrates a specific increase of AC6 but not AC5 mRNA in the zona glomerulosa of rats given a low sodium diet. AC9 mRNA was increased in all the three cortical zones of rats treated with ACTH. We suggest that AC6 and AC9 play important roles in different pathways associated with the regulation of aldosterone and corticosteroid production.     

Development of adrenal zonation in fetal rats defined by expression of aldosterone synthase and 11beta-hydroxylase

The adult rat adrenal cortex is comprised of three concentric steroidogenic zones that are morphologically and functionally distinguishable: the zona glomerulosa, zona intermedia, and the zona fasciculata/reticularis. Expression of the zone-specific steroidogenic enzymes, cytochrome P450 aldosterone synthase (P450aldo), and P450 11beta hydroxylase (P45011beta), produced by the zona glomerulosa and zona fasciculata/reticularis, respectively, can be used to define the adrenal cortical cell phenotype of these two zones. In this study, immunohistochemistry and in situ hybridization were used to determine the ontogeny of expression of P450aldo and P45011beta to monitor the pattern of development of the rat adrenal cortex. RIA was used to measure adrenal content of aldosterone and corticosterone, the resulting products of the two enzymatic pathways. Double immunofluorescent staining for both enzymes at gestational day 16 (E16) showed P45011beta protein expressed in cells distributed throughout most of the adrenal intermixed with a separate, but smaller, population of cells expressing P450aldo protein. Whereas expression of P45011beta protein retained a similar pattern of distribution from E16 to adulthood (ignoring distribution of SA-1 positive, presumptive medullary cells), P450aldo protein changed its pattern of distribution by E19, becoming localized in a discontinuous ring of cells adjacent to the capsule. By postnatal day 1, P450aldo protein distribution was similar to that observed in adult glands; P450aldo-positive cells formed a continuous zone underlying the capsule. In situ hybridization showed that the pattern of P45011beta messenger RNA expression paralleled protein expression at all times, whereas P450aldo messenger RNA paralleled protein at E19 and after, but was undetectable before E19. However, adrenal aldosterone and corticosterone, as measured by RIA, were detected by E16, supporting the functional capacity of both phenotypes for all ages studied. These data suggest that the development of the adrenal zona glomerulosa occurs in two distinct phases; initial expression of the glomerulosa phenotype in scattered cells of the inner cortex before E17, followed by a change in distribution to the outer cortex between E17 and E19. It is hypothesized that this change in distribution occurs via cell differentiation, rather than cell migration, and that a possible regulator of these events is the fetal renin-angiotensin system.     

Differential expression of SNAP-25 isoforms and SNAP-23 in the adrenal gland

In the rat adrenal gland, we previously observed that SNAP-25 is not restricted to the plasmalemma in noradrenergic cells as it is in adrenergic cells, and hypothesized that SNAP-25 isoform expression is different in the two phenotypes. Expression of SNAP-25 isoforms and SNAP-23 was examined by immunoblotting, immunofluorescence, and RT-PCR. Amplifications of SNAP-25 mRNAs were combined with Southern hybridization, restriction enzyme analysis, and sequencing of cloned PCR products to compare SNAP-25 isoform expression in rat and bovine adrenal glands. SNAP-25 and SNAP-23 mRNA and protein are expressed in the glands; SNAP-23 is enriched in the adrenal cortex, whereas SNAP-25 is restricted to the adrenal medulla. Furthermore, high levels of SNAP-25 and low levels of SNAP-23 are observed in the PC12 cells, whereas both SNAP-25 and SNAP-23 are expressed in adrenal medullary cultures. In all extracts, the SNAP-23 mRNA corresponded to SNAP-23a. SNAP-25a is the major form expressed in rat adrenal glands (75%), as it is in PC12 cells (80%), but both SNAP-25a and SNAP-25b (40% vs. 60%) are expressed in bovine adrenal medulla in situ and in culture. In addition, an enriched population of adrenergic cells (93%) expressed a higher level of SNAP-25b (70%), suggesting that this isoform may not be restricted to fast neurotransmission.     

A survey of Coccidia on 43 poultry farms in Argentina

This study aimed to characterize the influence of dietary salt intake on the gene expression of angiotensin II type 1 (AT1) receptor subtypes in different organs. Male Sprague-Dawley rats were fed low salt (0.2 mg/g), normal salt (6 mg/g), or high salt (40 mg/g) diets for 5, 10, and 20 days. mRNA levels for the two AT1 receptor subtypes were determined in adrenal gland, kidney, liver, and lung. In all of the organs examined, with the exception of the adrenal glands, low salt diet led to a transient decrease in the abundance of AT1A receptor mRNA but not of AT1B mRNA, which reached their nadirs between days 5 and 10 of feeding. In the adrenal gland, in which the AT1B receptor is predominant, low salt diet led to a transient increase in the expression of this receptor gene, with a maximum around day 10 of feeding. High salt diet exerted no significant influence on AT1 receptor gene expression in these organs. These findings indicate that the rate of salt intake, in particular, a reduction of salt intake, significantly influences AT1 receptor gene expression in an organ-, time-, and subtype-dependent fashion. It appears that AT1 receptor subtypes are differentially influenced by low salt intake, in that AT1B receptor gene expression increases and AT1A receptor gene expression decreases in this situation. This differential response of AT1 receptor gene expression may be relevant for the organism to be able to adapt to a reduction in oral salt intake.     

Angiotensin antagonists and the adrenal cortex and medulla

Several analogs of angiotensin in which the phenylalanine in position 8 of the peptide chain was replaced by an aliphatic amino acid residue are specific antagonists of angiotensin in aorta, the adrenal medulla, and adrenal zona glomerulosa. In the adrenal cortex and medulla, all actapeptide analogs have more agonist activity than in aortic strips. In studies with N-terminally substituted analogs, it appears that adrenal degradation of the angiotensin molecule by aminopeptidase(s) does not occur or is not retarded by N-terminal mocifications such as sarcosine substitution. The decapeptide analog [Ile8]-angiotensin I and heptapeptide analog [des-Asp1, Ile8]-angiotensin II were excellent antagonists in the adrenal medulla and each peptide was devoid of intrinsic activity. These substituted homologs of angiotensin may offer a novel approach for the development of selective antagonists of angiotensin receptors. In the adrenal cotex, [des-Asp1, Ile8]-heptapeptide possessed greater receptor affinity than any of the angiotensin octapeptides studied. This C-terminally substituted heptapeptide does have significant intrinsic activity in the adrenal cortex which would limit the use of this compound as an antagonist of vascular responses to angiotensin II. In studies with [Ile8]-angiotensin II, [Sar1, Ile8]-angiotensin II, and [des-Asp1, Ile8]-angiotensin II, the pA2 values calculated indicate that the N-terminal residue is not important for receptor binding in the adrenal cortex but may be of significance in binding to adrenal medullary and aortic smooth muscle receptors. At the present time it appears unlikely that any single animal model or assay system can reliably predict the agoinst/antagonist activities of angiotensin analogs for all the various end organs which respond to the angiotensins.     

Expression patterns of class I and class IV alcohol dehydrogenase genes in developing epithelia suggest a role for alcohol dehydrogenase in local retinoic acid synthesis

Vitamin A (retinol) regulates embryonic development and adult epithelial function via metabolism to retinoic acid, a pleiotrophic regulator of gene expression. Retinoic acid is synthesized locally and functions in an autocrine or paracrine fashion, but the enzymes involved remain obscure. Alcohol dehydrogenase (ADH) isozymes capable of metabolizing retinol include class I and class IV ADHs, with class III ADH unable to perform this function. ADHs also metabolize ethanol, and high levels of ethanol inhibit retinol metabolism, suggesting a possible mode of action for some of the medical complications of alcoholism. To explore whether any ADH isozymes are linked to retinoic acid synthesis, herein we have examined the expression patterns of all known classes of ADH in mouse embryonic and adult tissues, and also measured retinoic acid levels. Using in situ hybridization, class I ADH mRNA was localized in the embryo to the epithelia of the genitourinary tract, intestinal tract, adrenal gland, liver, conjunctival sac, epidermis, nasal epithelium, and lung, plus in the adult to epithelia within the testis, epididymis, uterus, kidney, intestine, adrenal cortex, and liver. Class IV ADH mRNA was localized in the embryo to the adrenal gland and nasal epithelium, plus in the adult to the epithelia of the esophagus, stomach, testis, epididymis, epidermis, and adrenal cortex. Class III ADH mRNA, in contrast, was present at low levels and not highly localized in the embryonic and adult tissues examined. We detected significant retinoic acid levels in the fetal kidney, fetal/adult intestine and adrenal gland, as well as the adult liver, lung, testis, epididymis, and uterus--all sites of class I and/or class IV ADH gene expression. These findings indicate that the expression patterns of class I ADH and class IV ADH, but not class III ADH, are consistent with a function in local retinoic acid synthesis needed for the development and maintenance of many specialized epithelial tissues.     

Implication of ZOG protein (zona glomerulosa-specific protein) in zone development of the adrenal cortex

The three zones of adrenal cortex are thought to arise from a single multipotential stem cell. Immunohistochemical studies of fetal and adult adrenals using an antibody against a previously-cloned ZOG protein, a rat homolog of Pref-1, were conducted to explore its roles in the differentiation of cortical tissues. At the early embryonic stage, ZOG was already expressed in adrenogonadal primordial cells. The ZOG-positive cells gradually formed the adrenal primordium by E14.5. By E17.5 the expression was repressed in the inner part of the aggregate and these cells began to express CYP11B1. The ZOG-positive cells at this stage existed at the periphery of the aggregate but they did not express CYP11B2 yet. Not until E20.5 did the aldosteronogenic cells appear among the ZOG-positive cells at the outermost part of the gland. Based on these and the other findings the zonal development of the adrenal cortex is discussed.     

Vasopressin receptors modulate the pharmacological phenotypes of Cushing's syndrome

We have examined the expression profiles of the different vasopressin receptors (V1, V2, V3) that can be expressed in the three different types of tumors associated with Cushing's syndrome. V3 (V1b) receptor cDNA was cloned from a pituitary tumor responsible for Cushing's disease. We show that it is overexpressed in these tumors and can respond to DD-AVP. High expression of the V3 receptor on highly differentiated, ACTH-secreting, bronchial carcinoid tumors explain why these non-pituitary tumors occasionally respond to vasopressin, mimicking a "pituitary-like" behavior. A retrospective analysis showed that vasopressin induced an ACTH-independent cortisol rise in 27% of the adrenocortical tumors responsible for Cushing's syndrome. V1 mRNA was detected in normal adrenal cortex and in all tumors. Adenomas had significantly higher levels than carcinomas. V1 mRNA levels were higher in responders than in non-responders. One adenoma which had a brisk cortisol response in vivo, also had in vitro cortisol responses that were inhibited by a specific V1 antagonist. In situ hybridization showed the presence of V1 mRNA in the normal human adrenal cortex where the signal predominated in the compact cells of the zona reticularis. A positive signal was also present in the tumors with high V1 mRNA levels determined by RT-PCR; its distribution pattern was heterogeneous and showed preferential association with compact cells. High-and not ectopic-expression of the V1 receptor occurs in a minority of adrenal cortical tumors which become directly responsive to vasopressin stimulation.     

The influence of dose and dose rate on the incidence of neoplastic disease in RFM mice after neutron irradiation

The effect of circadian rhythm and alterations in posture on plasma aldosterone concentration was studied in 13 patients with primary aldosteronism (six adenoma, five idiopathic hyperplasia, two carcinoma) to define the regulatory mechanism in each of these pathologic subtypes. Blood samples for aldosterone, cortisol, renin, and potassium concentrations were obtained every 4 h during prolonged recumbency (32 h) and upright posture (16 h). During recumbency, aldosterone and cortisol followed a normal circadian pattern in patients with adenoma and hyperplasia, with peak values at 0400-0800 h and the nadir at 1600-2400 h. Normalized aldosterone and cortisol values correlated significantly in both groups (adenoma r=+0.66, P less than 0.001; hyperplasia r=+0.42, P less than 0.01). With upright posture, aldosterone levels declined parallel to the normal circadian fall in cortisol in patients with adenoma (r=+0.68, P less than 0.001); whereas aldosterone levels increased in patients with hyperplasia parallel to small increments in renin (r=+0.65, P less than 0.001) and potassium (r=+0.64, P less than 0.001). During the administration of dexamethasone, aldosterone no longer correlated with cortisol in patients with adenoma but continued to correlate with renin during upright studies in patients with hyperplasia (r=+0.77, P less than 0.01). Aldosterone circadian rhythm was abnormal in patients with carcinoma and no effect of posture was noted. Unilateral adrenalectomy restored the normal postural relationship in four patients with adenoma. These studies suggest that aldosterone secretion is under continuous ACTH control regardless of posture in patients with adenoma, whereas persistent adrenal responsiveness to small increments in renin and/or potassium mediate the postural increase in plasma aldosterone in patients with hyperplasia. True adrenal autonomy occurs only in patients with adrenal carcinoma and when ACTH is suppressed in those with adenoma.     

Aspirin improves endothelial dysfunction in atherosclerosis

Archival paraffin-embedded tissue from 5 normal adrenal glands (including 1 from a fetus of 28 weeks' gestation), 6 cases of adrenal cortical hyperplasia, 9 cortical adenomas, 14 cortical carcinomas, and 11 pheochromocytomas were immunostained with monoclonal antibody against bcl-2. Ultrastructural localization of bcl-2 protein was also performed on selected cases. Positive immunostaining for bcl-2 was seen in all of the layers of the normal adrenal cortex, with different staining characteristics. bcl-2 expression was never observed in the normal adrenal medulla. Electron microscopic studies revealed bcl-2 to be localized predominantly to mitochondria, with a small number of labels along the nuclear envelope. Analysis of adrenal neoplasms showed expression of bcl-2 in cortical tumors, but only one positive case in pheochromocytomas. Restriction of bcl-2 expression to adrenal cortex-derived tissue versus adrenal medulla-derived tissue might prove to be helpful for the differential diagnosis between cortical and medullary tumors.     

Functional role of focal adhesion kinase in the process of implantation

While it is well known that unilateral tissue ischemia may result in contralateral damage in some paired organs, there is no universally accepted mechanism to explain why these contralateral changes occur. The aim of the present study was to investigate the ultrastructural and hormonal changes that occur in the contralateral nonischemic adrenal gland after unilateral ischemia of an adrenal gland in a rat model. The animals were divided into four groups of four rats each; namely, a control group which received a sham operation without any ischemic insult, a 2-h ischemic group, a 4-h ischemic group, and an 8-h ischemic group. The left adrenal blood vessels were ligated in all ischemia groups and blood samples were taken for hormonal study 2, 4, and 8 h later, after which bilateral adrenalectomy was performed to determine the ultrastructural changes. The plasma concentrations of aldosterone and cortisol were determined by radioimmunoassays. There was an increase in both aldosterone and cortisol levels related to the duration of the ischemia, but the differences among the groups were not statistically significant. Contralateral ultrastructural damage such as heterochromatin in nuclei, mitochondrial degeneration, endoplasmic reticulum cisternal widening, increased lipid droplets, and lysosomes, were demonstrated electron-microscopically after unilateral adrenal ischemia.     

Strain differences in adrenal microsomal steroid metabolism in guinea pigs

We recently reported that CYP2D16, a xenobiotic-metabolizing P450 isozyme, was expressed at higher levels in adrenal microsomes from inbred Strain 13 guinea pigs than in those from outbred English Short Hair (ESH) animals. Studies were done to determine if there also were strain differences in adrenal microsomal steroid metabolism. In both inner (zona reticularis) and outer (zona fasciculata plus zona glomerulosa) zone preparations of the adrenal cortex, 21-hydroxylase activities were greater in microsomes from ESH than from Strain 13 guinea pigs. By contrast, 17alpha-hydroxylase activities were similar in the two strains. In both strains, 21-hydroxylase activities were greater in inner than outer zone microsomes, but the opposite was found for 17alpha-hydroxylase activities (outer>inner). Northern and Western analyses revealed higher levels of CYP21 mRNA and protein in adrenals from ESH than Strain 13 guinea pigs, but there were no strain differences in CYP17 mRNA or protein concentrations. Despite the zonal differences in adrenal 17alpha-hydroxylase and 21-hydroxylase activities, CYP17 and CYP21 mRNA and protein levels were similar in the inner and outer zones within each strain of guinea pig. The results demonstrate strain differences in microsomal steroid metabolism that are explained by differences in CYP21 expression. By contrast, the zonal differences in steroid hydroxylase activities may be attributable to post-translational mechanisms.     

Immunolocalization of dehydroepiandrosterone sulfotransferase in normal and pathologic human adrenal gland

Dehydroepiandrosterone sulfotransferase (DHEA-ST) catalyzes the conversion of dehydroepiandrosterone (DHEA) to dehydroepiandrosterone sulfate (DHEA-S) in the adrenals. Both DHEA and DHEA-S are quantitatively the most important corticosteroids in human. In this study, DHEA-ST was immunolocalized in normal (5 cases) and neoplastic human adrenal glands (33 cases), using a specific IgG fraction raised against the enzyme. DHEA-ST was present in almost all the zona reticularis cells and some cortical cells demonstrating lipid depletion in the zona fasciculata but not in the zona glomerulosa of the normal adrenal. This finding is consistent with adrenocorticotrophic hormone dependency of the enzyme expression. In adrenocortical adenoma, DHEA-ST immunoreactivity was observed in all the cases of Cushing's adenoma, adenoma associated with pre-Cushing's syndrome, nonfunctioning, hormonally inactive adenoma, and two of seven cases of aldosteronoma, but distribution of immunoreactivity was markedly heterogeneous among the adenoma cases. In attached non-neoplastic adrenal glands of the adenoma, intense and diffuse immunoreactivity was observed in the zona reticularis cells in all the cases of aldosteronoma and five of six of the nonfunctioning hormonally inactive adenoma, but DHEA-ST immunoreactivity was not observed or sporadic in the attached adrenal glands of Cushing's adenoma and adenoma with pre-Cushing's syndrome. These results in the attached adrenal gland may be correlated with decreased DHEA-ST expression due to autonomous neoplastic cortisol secretion and subsequent adrenocorticotrophic hormone suppression. In adrenocortical carcinoma, DHEA-ST was observed in all the cases, but the relative immunointensity of carcinoma cells was weak compared to that of the zona reticularis of the normal adrenal and adenoma.     

Expression of type 2 11beta-hydroxysteroid dehydrogenase and corticosteroid hormone receptors in early human fetal life

In adult life, the type 2 isozyme of 11beta-hydroxysteroid dehydrogenase (11betaHSD2) protects the mineralocorticoid receptor (MR) from glucocorticoid by inactivating cortisol to cortisone. 11betaHSD2 activity has been reported in human fetal tissues, where glucocorticoids may impair fetal growth yet are also required for normal fetal development. Using digoxigenin-labeled complementary ribonucleic acid (RNA) probes and an in-house 11betaHSD2 antiserum, we have analyzed the expression of 11betaHSD2, MR, and glucocorticoid receptor (GR) in human fetal tissues of gestational age 6-17 weeks (n=15). 11BetaHSD2 expression was absent at gestational age 6+ weeks, but was expressed in abundance in many fetal tissues between 8-12 weeks. At this time, 11betaHSD2 colocalized with GR messenger RNA (mRNA) expression in metanephros, gut, muscle, spinal cord and dorsal root ganglia, periderm, sex chords of testis, and adrenal. In particular within fetal kidney, intense expression of 11betaHSD2 and GR mRNA was observed over Bowman's capsule and the vascular tufts of developing glomeruli as they migrated from the surface of the kidney to the inner cortex. Only lung and adrenal medullary rests demonstrated high levels of GR mRNA but low levels of 11betaHSD2. 11BetaHSD2 mRNA and immunoreactivity staining patterns were similar, with the exception of the fetal adrenal, where mRNA was localized to the outer definitive zone but immunoreactivity was localized to the inner fetal zone. Colocalization of 11betaHSD2 (and GR mRNA) with MR mRNA was observed principally within epithelial cells of collecting ducts, particularly after 16 weeks gestation when the pattern of distribution of 11betaHSD2 became more adult in nature. High levels of MR mRNA were observed within developing bone. The data indicate that 11betaHSD2 in fetal life principally modulates ligand access to the GR in most fetal tissues, notably glomeruli and tubules in the developing kidney, testis, and periderm, and this may be have ramifications for fetal sodium homeostasis and differentiation. The development of tissues previously shown to have a critical requirement for glucocorticoids, such as lung and adrenal medulla, is facilitated by the expression of GR mRNA, but not 11betaHSD2. The expression of MR mRNA in high abundance in bone suggests a role for corticosteroids in human bone development, and the low/absent expression of 11betaHSD2 at this site suggests that it is functionally acting as a GR.