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Calmodulin-binding proteins in subcellular fractions of zones of the adrenal cortex.

The guinea pig adrenal cortex consists of a steroidogenic ACTH-responsive outer zone and an ACTH-unresponsive inner zone. It has been suggested that calmodulin plays an important role in ACTH-stimulated steroidogenesis. Thus, in an effort to examine the calmodulin 'system' in the guinea pig adrenal cortex model, Ca2+-dependent binding of calmodulin to proteins in subcellular fractions of the outer and inner zones was examined by the [125I]iodocalmodulin overlay technique and compared to similar studies utilizing pancreas, brain and liver tissue. Although the general pattern of calmodulin-binding proteins was similar for the two adrenocortical zones, quantitatively there was a striking difference with greater binding in the outer zone; this was particularly noteworthy for the mitochondrial fraction. The two most prominent calmodulin-binding proteins isolated from cytosol by calmodulin-Sepharose column chromatography had Mr of 60,000 and 47,000. The size of these two proteins suggested the presence of Ca2+/calmodulin-dependent protein kinase II. Western blot analysis, however, failed to demonstrate calmodulin kinase II in either zone, although it was clearly detectable in brain cytosol. The 60 K calmodulin-binding protein in the adrenal cortex also suggested the presence of the calmodulin-binding A subunit of the Ca2+/calmodulin-stimulated protein phosphatase, calcineurin. Western blot analysis did reveal the presence of calcineurin in the outer adrenocortical zone; it was not detectable, however, in the inner adrenocortical zone. The relation between the striking zonal differential for calmodulin-binding proteins and the zonal differential in ACTH-stimulated steroidogenesis in the guinea pig adrenal cortex will require further investigation.

Adrenal Cortex↗

Import and processing of the precursor of cytochrome P-450(SCC) by bovine adrenal cortex mitochondria.

Isolated bovine adrenal cortex mitochondria imported in vitro synthesized pre-P-450(SCC) and processed it to the mature form. Partial radio-sequencing of the processed P-450(SCC) gave a result identical with that for authentic P-450(SCC). Rat liver mitochondria also imported pre-P-450(SCC) and processed it to the mature form, whereas bovine heart mitochondria were unable to import and process pre-P-450(SCC) although both mitochondrial preparations imported and processed pre-adrenodoxin. The pre-P-450(SCC) processing activity of bovine adrenal cortex mitochondria was associated with the matrix side surface of the inner membrane. The processing protease could be solubilized by sodium cholate and partially purified by ammonium sulfate fractionation. The partially purified processing protease cleaved pre-P-450(SCC) at the correct position. It was also active in processing pre-P-450(11 beta) but inactive toward pre-adrenodoxin. Bovine heart mitochondria lacked the processing activity to pre-P-450(SCC). The localization of pre-P-450(SCC) and mature P-450(SCC) in bovine adrenal cortex mitochondria was examined. Mature P-450(SCC) processed by the mitochondria was found associated with the matrix-side surface of the inner membrane, which is the correct location of P-450(SCC) in the cell. In the presence of o-phenanthroline, pre-P-450(SCC) was imported into the organelles without being processed and remained soluble in the matrix. The incorporation of newly processed mature P-450(SCC) into the inner membrane was also observed when pre-P-450(SCC) was incubated with inner membrane vesicles. Mature P-450(SCC) generated in vitro from pre-P-450(SCC) by the partially purified processing protease was incorporated not only into the inner membrane vesicles but also into bovine adrenal cortex microsomes. These findings suggested that the processing of pre-P-450(SCC) occurred prior to the incorporation of mature-P-450(SCC) into the inner membrane.

Adrenal Cortex↗

Heterogenous inositol tetrakisphosphate binding sites in the adrenal cortex.

Bovine adrenal cortical microsomes possess high (Kd = 3.68 +/- 1.02 X 10(-9) M) and lower (Kd = 9.20 +/- 1.71 X 10(-8) M) affinity binding sites for inositol 1,3,4,5-tetrakisphosphate. The binding to these sites is rapid, saturable (reaches equilibrium by 15 min at 0 degrees C), and reversible. Competition studies with other inositol phosphate analogs indicate that the high affinity binding sites are clearly distinct from the inositol 1,4,5-trisphosphate receptors which are, however, responsible for a fraction of the lower affinity binding. The characteristics of the inositol 1,3,4,5-tetrakisphosphate binding sites described are compatible with their possible receptor function.

Adrenal Cortex↗

The mitochondrial malic enzymes. I. Submitochondrial localization and purification and properties of the NAD(P)+-dependent enzyme from adrenal cortex.

Rat and calf adrenal cortex homogenates were found to contain three different malic enzymes. Two were strictly NADP+-dependent and were localized, one each, in the cytosol and the mitochondrial fractions, respectively. These two enzymes appear to be identical to those described by Simpson and Estabrook (Simpson, E. R., and Estabrook, R. W. (1969) Arch. Biochem. Biophys. 129, 384-395). The third was NAD(P)+-linked and was present in the mitochondrial fraction only. All three malic enzymes separated as distinct bands during electrophoresis on 5 percent polyacrylamide slab gels at pH 9.0. Marker enzymes and the mitochondrial malic enzymes migrated together in intact mitochondria during sucrose density gradient centrifugations despite changes in the equilibrium position of the mitochondria promoted by energy-dependent calcium phosphate accumulation. In adrenal cortex mitochondria subfractionated by the method of Sottocasa et al. (SOTTOCASA, G.L., KUYLENSTIERNA, B., ERNSTER, L., and BERGSTAND, A. (1967) J. Cell Biol. 32, 415-438), both malic enzymes were associated with the inner membrane-matrix space. Sonication solubilized the two malic enzymes along with the matrix space marker enzymes. The NAD(P)+-dependent malic enzyme was purified 100-fold from calf adrenal cortex mitochondria. The final preparation was free of malic dehydrogenase, fumarase, the strictly NADP+-linked malic enzyme and adenylate kinase. Either Mn24 orMg2+ was required for activity and 1 mol of pyruvate was formed for each mole of NAD+ and NADP+ reduced. The pH optima with NAD+ and NADP+ were 6.5 tp 7.0 and 6.0 to 6.5, respectively. Michaelis-Menten kinetics were observed on the alkaline side. Fumarate, succinate, and isocitrate were positive and ATP and ADP were negative modulators of the regulatory enzyme. The modulators did not influence the stoichiometry and they were not metabolized during the reaction. Under Vmax conditions the ratios for the rate of NAD+:NADP+ reduction were 1.76 and 1.15 at pH 7.4 and 6.0, respectively. The apparent Michaelis constants also differed depending on the pH and the coenzyme. At pH 7.4 (in the presence of 5 mM fumarate) and at pH 6.0 (no fumarate) the Km values for (-)-malate, NAD+, and Mn2+ were 1.7, 0.16, and 0.15 mM, and 0.31, 0.06, and 0.09 mM, respectively. At pH 7.4 (5MM fumarate) and pH 6.0 (no fumarate), the Km values for (-)-malate, NADP+, and Mn2+ were 6.5, 0.62, and 0.59 mM, and 0.68. 0.12, and 0.31 mM, respectively. The apparent Ki values for ATP with NAD+ and NADP+ as coenzyme were 0.42 and 0.27 mM, respectively.

Adrenal Cortex↗

Basic fibroblast growth factor: production and growth stimulation in cultured adrenal cortex cells.

Cultured bovine adrenal cortex cells express the basic fibroblast growth factor (bFGF) gene and contain, but under normal conditions apparently do not release, bFGF. However, once released, bFGF can stimulate proliferation of the cells, indicating that it could act as a self-stimulating growth factor for adrenal cortex cells. It is conceivable that the intracellular bFGF is released upon injury of the adrenal cortex and that it may be involved in the subsequent tissue repair mechanisms by stimulating the proliferation of adrenal cortical and vascular endothelial cells.

Adrenal Cortex↗

[Evaluation of the secretory activity of the adrenal cortex and gonads in women with epilepsy. I. Urinary excretion of metabolites of adrenal cortex hormones in women with epilepsy during the 2 days preceding menstrual bleeding].

In 32 women with seizures occurring mainly in the premenstrual phase and during bleeding, (group A) and in 31 women with epilepsy without this relationship of the seizures to the menstrual cycle (group B) the metabolites of adrenocortical hormones (17-ketosteroids and 17-hydroxycorticosteroids) were determined in 24-hour urine. The investigations were done during 2 days preceding menstrual bleeding, in most cases during three menstrual cycles. A significant reduction of the excretion of 17-ketosteroids and total 17-hydroxycorticosteroids was found in both groups as compared to the accepted normal value (p less than 0.01). However, no significant difference was observed in the excretion of these hormones between these groups of patients, although in group A he values of 17-ketosteroids were lower than in group B. On the basis of these results it is suggested that deficiency of androgenic hormones may contribute to the occurrence of seizures on the days before the onset of menstrual bleeding, and the effect of anticonvulsant treatment on the decreased excretion of these hormones is discussed.

17-Hydroxycorticosteroids↗

[Development and regression of the fetal adrenal cortex].

The adrenal glands from a series of 300 fetuses and infants which had died in the Hospital Saint-Vincent-de-Paul, Paris, were dissected, weighed and processed for routine histology. The development of the fetal cortex and its regression have been compared to the general development of the gland. Our results show that there is an important development of the fetal cortex up to birth, when the adrenal glands represent almost one third of the size of the kidneys and possess only very reduced permanent cortex and practically no medulla. The regression of the fetal cortex in the postnatal period is marked by a decrease in weight of the adrenal glands up to the 2nd or 3rd month, by the persistence of a few dispersed cells up to the fifth month and by the persistence of a few fibrous elements up to 2 years of age.

Adrenal Cortex↗

Expression of the glucocorticoid receptor in the human adrenal cortex.

Glucocorticoids produced in the adrenal cortex act by binding to a specific intracellular protein, the glucocorticoid receptor (GR), which then modulates gene transcription in target tissues. Whether the adrenal cortex itself is a glucocorticoid target tissue has not been analyzed as yet. Since the presence of GR would be a prerequisite for such "intracortical" glucocorticoid action, this study was designed to analyze GR expression in the normal human adrenal gland using RT-PCR, Western blot, and immunohistochemistry. RT-PCR revealed the presence of GR mRNA in adrenal cortex as well as in NCIh295 cells. These results were confirmed at the protein level by Western blot employing a specific anti-human GR antibody. Immunohistochemically, weak GR staining was observed in the adrenal medulla. In contrast, GR was strongly expressed in the adrenal cortex with the zona reticularis showing the most intense staining. Transfection of a GR-responsive luciferase reporter gene into NCIh295 cells resulted in dexamethasone-dependent induction of luciferase activity, indicating that GR is functional in this tissue. In this study, we show for the first time that GR is expressed in the human adrenal cortex. Its preferential expression in the zona reticularis may indicate a functional role in the regulation of adrenal androgen biosynthesis.

Adrenal Cortex↗

Effects of dietary sodium on dopamine content of rat adrenal cortex.

Dopamine occurs in the adrenal cortex and appears to provide maximum tonic inhibition of aldosterone secretion. In the present experiments, the effects of high or low sodium (Na+) intake on concentrations of dopamine in the adrenal cortex of adult male Sprague-Dawley rats were examined. In the first experiment, sham-operated and adrenal demedullated rats were provided with 1.5% NaCl or tap water for drinking for 5 days. In the second experiment, sham-operated and adrenal demedullated rats were fed regular laboratory chow (approximately 0.45% NaCl) or low Na+ chow (0.001-0.005% NaCl) for 5 days. High Na+ intake was attended by dramatic increases in fluid consumption, urine production and Na+ excretion. However, high Na+ intake did not affect levels of dopamine, norepinephrine or epinephrine in the adrenal glands. Approximately 45% of adrenal dopamine but less than 4% of either norepinephrine or epinephrine was localized in the adrenal cortex. In the second experiment, animals fed a diet low in Na+ had a significant reduction in Na+ excretion but levels of adrenal catecholamines were unaffected. Approximately 36% of adrenal dopamine but less than 5% of either norepinephrine or epinephrine was localized in the adrenal cortex. These findings suggest that adrenal cortical dopamine concentrations remain relatively constant in spite of presumed differences in turnover rates of this neurohormone.

Adrenal Cortex↗

Nuclear DNA patterns in adrenal cortex proliferative lesions.

In cortical adrenal gland tumours there are discrepancies between morphological criteria for malignancy and biological behaviour. This makes it difficult to select the appropriate treatment. We have studied morphometric and DNA densitometric features of 24 adrenal proliferative lesions (hyperplasia, adenoma, and carcinoma) by means of slide cytometry. All variables have been correlated with pathological diagnosis. The samples were selected from paraffin-embedded tissue, and representative lesions were Feulgen stained. Densitometric study showed aneuploid cell lines in every carcinoma, 5 of 8 adenomas, and 5 of 10 hyperplastic lesions. Both DNA nuclear content (mean ploidy of 2.11 c, 2.41 c, and 3.05 c) mean nuclear area (average of 31.26 microns 2, 35.92 microns 2, and 42.39 microns 2) showed progressive increase from hyperplasia to adenoma, and carcinoma. Mean shape factors were lowest in adenomas (1.69) and highest in carcinomas (1.82). Those karyometric variables which showed statistically significant differences (p < 0.05) among diagnostic groups were included in a stepwise three-way discriminant analysis. Only three parameters, shape factor (p = 0.0008), mean ploidy (p = 0.0012), and adrenal weight (p = 0.0055) persisted as independent predictive factors. Using the three variables selected by discriminant analysis on our cases, 100% of the adenomas were correctly classified, 83% of the carcinomas, and 80% of the hyperplasias. Tumour weight and nuclear shape factor differentiated adrenal cortex adenoma from carcinoma, while mean ploidy distinguished adrenal cortical hyperplasia from carcinoma. Nuclear pleomorphism (shape factor) and DNA-ploidy are the most important nuclear features in predicting the biological course of proliferative adrenal cortex lesions, although by themselves they are not bona-fide discriminators.

Adenoma↗

Preliminary observations on the role of the mesonephros in the development of the adrenal cortex.

The interrelationship between mesonephros, adrenal cortex, and gonads was studied in 28- and 31-day old sheep fetuses by means of light microscopy on plastic sections. At these stages, the adrenal cortex is just beginning to develop and mesonephros is undergoing involution; its regression is accompanied by mobilization of cells from the glomerulus of a peculiar nephron situated in the proximal third of the organ, and referred to as "giant" because of its large size. The mobilized cells egress from this glomerulus organized in trabeculae, some of which reach the cranial extremity of the adrenal cortex while others coalesce into a prominent cellular formation which extends uninterrupted toward and into the developing gonads. In previous studies we have shown that the mesonephric cells which colonize the gonads differentiate into sustentacular and interstitial steroidogenic cells; the presence of an analogous cellular migration from the mesonephros to the adrenal cortex now suggests that also the adrenal cortical cells may be of mesonephric origin.

Adrenal Cortex↗

Specific lamellar structures of agranular endoplasmic reticulum in the senile mouse adrenal cortex.

In the adrenal cortex of old mice, lamellar bodies of various shapes frequently appear in the zona reticularis cells. These structures consist of electron dense plates, about 20 nm in width, closely piled at regular distances of about 25 nm. Each plate displays two sheets of unit membranes enclosing a dense material and with several clear spaces between them. These paired membranes usually terminate in round saccules at both ends, but occasionally continue to the tubules of surrounding agranular endoplasmic reticulum. Saccules in several rows, in combination with a part of the lamellae, may be arranged cirularly in the cytoplasm. From these observations, it is proposed that the lamellar body is composed of a cup-shaped mass of flattened cisternae of the agranular endoplasmic reticulum and each of the cisternae is attenuated and closed except at their marginal sacculations. The concentric or horseshoe-shaped profile of the lamellar body observed in this study is accounted for by different section planes through the cup-shaped structure.

Adrenal Cortex↗

Oestrogen induced hypertriglyceridaemia: role of the adrenal cortex.

The role of the adrenal cortex in the pathogenesis of hypertriglyceridaemia associated with the intake of oral contraceptive agents containing oestrogen has been investigated in rats. Bilateral adrenalectomy reduced the activity of hepatic enzymes regulating lipogenesis (acetyl CoA carboxylase, fatty acid synthetase) and decreased plasma triglyceride concentrations. On the other hand, the administration of high dosage corticosterone induced the activity of hepatic enzymes with consequent elevation in serum triglyceride levels. In animals with intact adrenals the administration of oestradiol: (a) raised plasma triglyceride levels, (b) enhanced the activity of hepatic enzymes, and (c) increased the adrenal cortex:body weight ratio. The effects (a) and (b) were not observed when both adrenals were removed prior to oestrogen therapy. High dosage corticosterone replacement was found to be essential for the oestradiol to produce its effects on hepatic enzymes and plasma triglyceride levels. The results suggest a regulatory role for the adrenal cortex in the homeostasis of plasma triglyceride concentration and that the hypertriglyceridaemia induced by the oestrogen containing preparations might be secondary to alterations in adrenocortical function.

Acetyl-CoA Carboxylase↗