STIMULATION OF ADRENAL 5-ENE,3β-HYDROXYSTEROID DEHYDROGENASE BY CORTICOTROPHIN IN VITRO

1978 ◽  
Vol 78 (3) ◽  
pp. 457-458 ◽  
Author(s):  
N. LOVERIDGE ◽  
W. R. ROBERTSON
Keyword(s):  
Adrenal Gland ◽  
Hydroxysteroid Dehydrogenase ◽  
Cellular Biology ◽  
Zona Fasciculata ◽  
Zona Reticularis ◽  
Cytochemical Bioassay ◽  
Low Concentrations ◽  
Kennedy Institute ◽  
Stimulation Of

Division of Cellular Biology, The Mathilda and Terence Kennedy Institute of Rheumatology, Bute Gardens, London, W6 7DW (Received 24 April 1978) It is well established (Chayen, Daly, Loveridge & Bitensky, 1976) that segments of guineapig adrenal gland can be maintained in vitro and will respond to low concentrations (0·005– 5·0 pg/ml) of corticotrophin (ACTH). The response measured in the cytochemical bioassay of ACTH is the loss of ascorbate from the zona reticularis (Chayen, Loveridge & Daly, 1972), which is directly related to secretion of cortisol by these segments (Chayen, Bitensky, Chambers, Loveridge & Daly, 1974). However, because both major zones of the adrenal cortex are involved in steroidogenesis (see, e.g., Symington, 1969; Hyatt, Bell, Gould, Tait & Tait, 1976), the lack of a response in the zona fasciculata seems to be anomalous. To test whether the cells of the zona fasciculata in guinea-pig adrenal segments can respond to low concentrations

scholarly journals Localisation of the melanocortin-2-receptor and its accessory proteins in the developing and adult adrenal gland

2011 ◽  
Vol 46 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Rebecca J Gorrigan ◽  
Leonardo Guasti ◽  
Peter King ◽  
Adrian J Clark ◽  
Li F Chan
Keyword(s):  
Adrenal Gland ◽  
Adrenal Cortex ◽  
Accessory Protein ◽  
Zona Fasciculata ◽  
Accessory Proteins ◽  
Similar Function ◽  
Glucocorticoid Deficiency ◽  
Inactivating Mutations

The melanocortin-2-receptor (MC2R)/MC2R accessory protein (MRAP) complex is critical to the production of glucocorticoids from the adrenal cortex. Inactivating mutations in either MC2R or MRAP result in the clinical condition familial glucocorticoid deficiency. The localisation of MC2R together with MRAP within the adrenal gland has not previously been reported. Furthermore, MRAP2, a paralogue of MRAP, has been shown in vitro to have a similar function to MRAP, facilitating MC2R trafficking and responsiveness to ACTH. Despite similar MC2R accessory functions, in vivo, patients with inactivating mutations of MRAP fail to be rescued by a functioning MRAP2 gene, suggesting differences in adrenal expression, localisation and/or function between the two MRAPs. In this study on the rat adrenal gland, we demonstrate that while MRAP and MC2R are highly expressed in the zona fasciculata, MRAP2 is expressed throughout the adrenal cortex in low quantities. In the developing adrenal gland, both MRAP and MRAP2 are equally well expressed. The MC2R/MRAP2 complex requires much higher concentrations of ACTH to activate compared with the MC2R/MRAP complex. Interestingly, expression of MC2R and MRAP in the undifferentiated zone would support the notion that ACTH may play an important role in adrenal cell differentiation and maintenance.

PROPERTIES OF RAT ADRENAL ZONA RETICULARIS CELLS: PRODUCTION AND STIMULATION OF CERTAIN STEROIDS

1979 ◽  
Vol 83 (3) ◽  
pp. 435-447 ◽  
Author(s):  
J. B. G. BELL ◽  
R. P. GOULD ◽  
P. J. HYATT ◽  
J. F. TAIT ◽  
S. A. S. TAIT
Keyword(s):  
Adrenal Cortex ◽  
Significant Role ◽  
Zona Fasciculata ◽  
Cell Type ◽  
Acth Stimulation ◽  
Specific Stimulus ◽  
Zona Reticularis ◽  
Cell Pool ◽  
Stimulation Of

The outputs of corticosterone, deoxycorticosterone and androstenedione from dispersed, purified rat adrenal zona reticularis and zona fasciculata cells have been measured by radioimmunoassay. Preferential production of deoxycorticosterone by zona reticularis cells was demonstrated by their higher basal deoxycorticosterone: corticosterone ratio when compared with zona fasciculata cells. Adrenocorticotrophin (ACTH) stimulated corticosterone output by all cell pools prepared by unit gravity (1 g) sedimentation, zona fasciculata cells being stimulated 130-fold compared with 20-fold for the zona reticularis cells in relation to their basal corticosterone output. In every cell pool, ACTH stimulated the output of corticosterone more than it stimulated the output of deoxycorticosterone. In parallel cell preparations, it was shown that ACTH increased the conversion of tracer amounts of radioactive deoxycorticosterone to corticosterone and decreased the conversion of radioactive corticosterone to 11-dehydrocorticosterone. Adrenocorticotrophin did not increase the conversion of radioactive deoxycorticosterone to total 11-oxygenated steroids (corticosterone+ 11-dehydrocorticosterone). It is unlikely therefore that ACTH stimulates 11 β-hydroxylation. Data indicate that the ratio of deoxycorticosterone to total 11-oxygenated steroids (corticosterone +11-dehydrocorticosterone) is characteristic for each cell type, and that this ratio will be relatively independent of ACTH stimulation or the amount of pregnenolone substrate available. Basal androstenedione outputs were similar for both types of cell, and ACTH stimulation was very small, being slightly greater for zona fasciculata than for zona reticularis cells. The contribution of the zona reticularis cells to the basal output of any steroid by the cells of the inner two zones of the adrenal cortex of the rat was relatively small (20% for deoxycorticosterone and 10% for corticosterone) and was even less after stimulation by ACTH. Unless a specific stimulus can be found, therefore, a significant role for the zona reticularis cannot yet be established.

EFFECT OF VARIOUS PREPARATIONS OF PITUITARY AND DIENCEPHALON ON THE IN VITRO SECRETION OF ALDOSTERONE AND CORTICOSTERONE BY THE RAT ADRENAL GLAND

1961 ◽  
Vol 39 (5) ◽  
pp. 901-913 ◽  
Author(s):  
O. J. Lucis ◽  
I. Dyrenfurth ◽  
E. H. Venning
Keyword(s):  
Adrenal Gland ◽  
Linear Relationship ◽  
Dose Response ◽  
Response Curve ◽  
Maximum Effect ◽  
Percentage Increase ◽  
Aldosterone Secretion ◽  
Maximal Stimulation ◽  
Stimulation Of

Purified corticotropin and ACTH peptides increased the secretion of aldosterone, corticosterone, and an unidentified compound RT4in incubated rat adrenal tissue. When the response was expressed as a percentage increase above that of the control tissue, the increases in corticosterone and compound RT4followed a sigmoid log dose – response curve. The maximum effect on aldosterone was obtained at a time when the response curve for corticosterone assumed a linear relationship between the response and the logarithm of the dose of ACTH. This dose level was considerably less than that required for maximal stimulation of corticosterone.The capacity of the ACTH peptides α1+α2and δ′ for stimulating aldosterone secretion could be greatly diminished by allowing solutions of these fractions to stand at 5 °C for 1 week. These solutions still retained their ability to stimulate corticosterone secretion.Saline suspensions and extracts of fresh hog diencephalon contained a factor which selectively stimulated aldosterone secretion.

Effects of endogenous calcium transport inhibitor from heart muscle on the active calcium uptake and passive calcium release properties of sarcoplasmic reticulum

1989 ◽  
Vol 67 (9) ◽  
pp. 999-1006 ◽  
Author(s):  
Njanoor Narayanan ◽  
Philip Bedard ◽  
Trilochan S. Waraich
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Heart Muscle ◽  
Calcium Release ◽  
Membrane Vesicles ◽  
Transport Inhibitor ◽  
Low Concentrations ◽  
Active Calcium ◽  
High Concentrations ◽  
Stimulation Of

In the present study, the effects of the cytosolic Ca2+ transport inhibitor on ATP-dependent Ca2+ uptake by, and unidirectional passive Ca2+ release from, sarcoplassmic reticulum enriched membrane vesicles were examined in parallel experiments to determine whether inhibitor-mediated enhancement in Ca2+ efflux contributes to inhibition of net Ca2+ uptake. When assays were performed at pH 6.8 in the presence of oxalate, low concentrations (<100 μg/mL) of the inhibitor caused substantial inhibition of Ca2+ uptake by SR (28–50%). At this pH, low concentrations of the inhibitor did not cause enhancement of passive Ca2+ release from actively Ca2+-loaded sarcoplasmic reticulum. Under these conditions, high concentrations (>100 μg/mL) of the inhibitor caused stimulation of passive Ca2+ release but to a much lesser extent when compared with the extent of inhibition of active Ca2+ uptake (i.e., twofold greater inhibition of Ca2+ uptake than stimulation of Ca2+ release). When Ca2+ uptake and release assays were carried out at pH 7.4, the Ca2+ release promoting action of the inhibitor became more pronounced, such that the magnitude of enhancement in Ca2+ release at varying concentrations of the inhibitor (20–200 μg/mL) was not markedly different from the magnitude of inhibition of Ca2+ uptake. In the absence of oxalate in the assay medium, inhibition of Ca2+ uptake was observed at alkaline but not acidic pH. These findings imply that the inhibition of Ca2+ uptake observed at pH 6.8 is mainly due to decrease in the rate of active Ca2+ transport into the membrane vesicles rather than stimulation of passive Ca2+ efflux; at alkaline pH (pH 7.4), enhanced Ca2+ efflux contributes substantially, if not exclusively, to the decrease in Ca2+ uptake observed in the presence of the inhibitor. It is suggested that if the cytosolic inhibitor has actions similar to those observed in vitro in intact cardiac muscle, acid–base status of the intracellular fluid would be a major factor influencing the nature of its effects (inhibition of Ca2+ uptake or stimulation of Ca2+ release) on transmembrane Ca2+ fluxes across the sarcoplasmic reticulum.Key words: sarcoplasmic reticulum, Ca2+ uptake, Ca2+ release, endogenous inhibitor, heart muscle.

EFFECTS OF HYDROXYSTEROID DEHYDROGENASE INHIBITORS ON IN-VITRO AND IN-VIVO STEROIDOGENESIS IN THE OVINE ADRENAL GLAND

1982 ◽  
Vol 92 (2) ◽  
pp. 205-212 ◽  
Author(s):  
P. SINGH-ASA ◽  
G. JENKIN ◽  
G. D. THORBURN
Keyword(s):  
Adrenal Gland ◽  
Incubation Medium ◽  
Bovine Serum ◽  
Hydroxysteroid Dehydrogenase ◽  
Inhibitory Effect ◽  
Bovine Serum Albu ◽  
Stimulatory Action ◽  
Adrenal Steroidogenesis

The effectiveness of trilostane and azastene as inhibitors of adrenal steroidogenesis was compared by in-vitro and in-vivo methods. A radioimmunoassay was developed for the measurement of cortisol in ovine plasma, incubation medium and tissue extract using a specific antiserum raised against cortisol 21-acetate,3-carboxymethyloxime : bovine serum albu Trilostane (20 μmol/l) decreased cortisol synthesis and release both in unstimulated and in ACTH-stimulated adrenal tissues in vitro. The same concentration of azastene had a lesser effect on unstimulated adrenals and was completely ineffective in blocking the stimulatory action of ACTH. In vivo, trilostane suppressed adrenal steroidogenesis in pregnant and cyclic ewes but the suppression in pregnant ewes was over a longer period, and after lower doses. It is concluded that trilostane had an inhibitory effect on ovine adrenal steroidogenesis both in vitro and in vivo.

Adrenal 11-beta hydroxysteroid dehydrogenase activity in response to stress

2004 ◽  
Vol 82 (6) ◽  
pp. 422-425 ◽  
Author(s):  
Marisa Zallocchi ◽  
Laura Matkovic ◽  
María C Damasco
Keyword(s):  
Adrenal Gland ◽  
Dehydrogenase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Stress Conditions ◽  
Methyl Transferase ◽  
Response To Stress ◽  
Stimulation Of

This work studied the effect of stresses produced by simulated gavage or gavage with 200 mmol/L HCl two hours before adrenal extraction, on the activities of the 11β-hydroxysteroid dehydrogenase 1 and 11β-hydroxysteroid dehydrogenase 2 isoforms present in the rat adrenal gland. These activities were determined on immediately prepared adrenal microsomes following incubations with 3H-corticosterone and NAD+ or NADP+. 11-dehydrocorticosterone was measured as an end-product by TLC, and controls were adrenal microsomes from rats kept under basal (unstressed) conditions. 11β-hydroxysteroid dehydrogenase 1 activity, but not 11β-hydroxysteroid dehydrogenase 2 activity, was increased under both stress-conditions. Homeostatically, the stimulation of 11β-hydroxysteroid dehydrogenase 1 activity would increase the supply of glucocorticoids. These, in turn, would activate the enzyme phenylethanolamine N-methyl transferase, thereby improving the synthesis of epinephrine as part of the stress-response.Key words: acidosis, adrenal, HSD, stress.

scholarly journals Effect of adrenomedullin infusion on basal and stimulated aldosterone secretion in conscious sheep with cervical adrenal autotransplants

2000 ◽  
Vol 166 (2) ◽  
pp. 389-399 ◽  
Author(s):  
R Salemi ◽  
JG McDougall ◽  
KJ Hardy ◽  
EM Wintour
Keyword(s):  
Adrenal Gland ◽  
Zona Glomerulosa ◽  
Cortisol Secretion ◽  
Aldosterone Secretion ◽  
Stimulation Experiments ◽  
Gland Function ◽  
Conscious Sheep ◽  
Stimulation Of

In vivo and in vitro studies have shown conflicting effects of adrenomedullin (ADM) on the secretion of steroid hormones from the adrenal gland. While some investigators report no effect of this peptide on the output of various hormones, others have reported both stimulatory and inhibitory roles for ADM. We have shown that basal aldosterone secretion rate (ASR), in conscious sheep with cervical adrenal autotransplants, did not change when ADM was infused directly into the adrenal arterial supply. While not affecting basal ASR, ADM did produce pronounced increases in adrenal blood flow (BF). This elevation of BF in association with ADM infusion was seen in all subsequent experiments. When aldosterone output was acutely stimulated by angiotensin II (AngII), potassium chloride (KCl) and adrenocorticotrophic hormone (ACTH), ADM was seen to drastically reduce the secretion of aldosterone with all agonists studied. After pre-exposure to ADM, all three agonists increased ASR but the magnitude of the responses were somewhat blunted. ADM did not have the same effect on cortisol secretion stimulated by ACTH, suggesting that the ability of this peptide to influence adrenal gland function is limited to the zona glomerulosa. In conditions of chronic elevation of aldosterone levels, such as in Na deficiency, ADM did not display the same inhibitory abilities seen in the acute stimulation experiments. Hence, ADM has been shown to have a direct, inhibitory role on the acute stimulation of aldosterone by AngII, KCl and ACTH while not affecting basal or chronic aldosterone secretion or cortisol secretion stimulated by ACTH.

scholarly journals Melanocortin receptor accessory proteins in adrenal gland physiology and beyond

2013 ◽  
Vol 217 (1) ◽  
pp. R1-R11 ◽  
Author(s):  
T V Novoselova ◽  
D Jackson ◽  
D C Campbell ◽  
A J L Clark ◽  
L F Chan
Keyword(s):  
Adrenal Gland ◽  
Energy Homeostasis ◽  
Functional Expression ◽  
Surface Expression ◽  
Vital Role ◽  
Melanocortin Receptor ◽  
Exocrine Function ◽  
Zona Fasciculata ◽  
Accessory Factor

The melanocortin receptor (MCR) family consists of five G-protein-coupled receptors (MC1R–MC5R) with diverse physiological roles. MC1R controls pigmentation, MC2R is a critical component of the hypothalamic–pituitary–adrenal axis, MC3R and MC4R have a vital role in energy homeostasis and MC5R is involved in exocrine function. The melanocortin receptor accessory protein (MRAP) and its paralogue MRAP2 are small single-pass transmembrane proteins that have been shown to regulate MCR expression and function. In the adrenal gland, MRAP is an essential accessory factor for the functional expression of the MC2R/ACTH receptor. The importance of MRAP in adrenal gland physiology is demonstrated by the clinical condition familial glucocorticoid deficiency, where inactivating MRAP mutations account for ∼20% of cases. MRAP is highly expressed in both the zona fasciculata and the undifferentiated zone. Expression in the undifferentiated zone suggests that MRAP could also be important in adrenal cell differentiation and/or maintenance. In contrast, the role of adrenal MRAP2, which is highly expressed in the foetal gland, is unclear. The expression of MRAPs outside the adrenal gland is suggestive of a wider physiological purpose, beyond MC2R-mediated adrenal steroidogenesis.In vitro, MRAPs have been shown to reduce surface expression and signalling of all the other MCRs (MC1,3,4,5R). MRAP2 is predominantly expressed in the hypothalamus, a site that also expresses a high level of MC3R and MC4R. This raises the intriguing possibility of a CNS role for the MRAPs.

Inhibition of corticosteroid production by sodium pentobarbitone in rat adrenocortical preparations

1993 ◽  
Vol 136 (1) ◽  
pp. 75-83 ◽  
Author(s):  
B. J. Whitehouse ◽  
S. J. Purdy ◽  
D. R. E. Abayasekara
Keyword(s):  
Intact Animal ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Steroid Production ◽  
Adrenal Cells ◽  
Glomerulosa Cells ◽  
Pituitary Adrenal Axis ◽  
Zona Glomerulosa Cells ◽  
Stimulation Of

ABSTRACT It is possible that some of the effects of sodium pentobarbitone on the hypothalamo-pituitary-adrenal axis in the intact animal may be attributable to direct actions on the adrenal cortex. The effects of the barbiturate on steroid production by rat adrenal preparations in vitro have therefore been examined. In zona glomerulosa cells, pentobarbitone inhibited basal steroid production in a dose-related fashion. For aldosterone and corticosterone, the doses required for 50% inhibition of production (IC50) were 1·2 mmol pentobarbitone/l and 3·7 mmol/l respectively. Steroidogenesis was inhibited at lower levels of pentobarbitone in the presence of 1 nmol ACTH/l (IC50 = 0·5 mmol pentobarbitone/l for aldosterone and 2·2 mmol/l for corticosterone). In zona fasciculata/reticularis cells, production of corticosterone was similarly reduced with an IC50 of 2·8 mmol pentobarbitone/l for basal production and 1·3 mmol/l for ACTH-stimulated production. The dose-related increases in corticosterone production produced by ACTH (0·1–1000 pmol/l) or dibutyryl cyclic AMP (0·1–1·0 mmol/l) were also eliminated in the presence of 2 mmol pentobarbitone/l. The effects of pentobarbitone (1–4 mmol/l) on the production of pregnenolone and deoxycorticosterone (DOC) were also studied. In zona fasciculata/reticularis cells, the responses of both pregnenolone and DOC were bell-shaped with increases at 1 mmol pentobarbitone/l, which fell back to control levels at 4 mmol pentobarbitone/l. Stimulation of DOC, accompanied by decreases in aldosterone and corticosterone production, was also seen in zona glomerulosa cells at 1 mmol pentobarbitone/l. The effect of 1 mmol pentobarbitone/l on the conversion of 22(R)-hydroxycholesterol (5-cholestene-3β,22(R)-diol), pregnenolone, progesterone and DOC to corticosterone and aldosterone by zona glomerulosa preparations was studied. There was a comparable reduction in the conversion of these precursors (2 μmol/l) to aldosterone with yields decreased to 20–30% of those found in the absence of pentobarbitone. The dose required for 50% reduction of the conversion of progesterone (2 μmol/l) to aldosterone was 0·55 mmol pentobarbitone/l and for corticosterone the dose was 1·75 mmol pentobarbitone/l. The results obtained show that pentobarbitone is an effective inhibitor of corticosteroid biosynthesis in rat adrenal cells, and suggest that its effects are brought about by inhibition of cytochrome P450-mediated hydroxylations. Journal of Endocrinology (1993) 136, 75–83

VERGLEICHENDE UNTERSUCHUNGEN ZUR BIOGENESE VON STEROIDHORMONEN BEI DURCHSTRÖMUNG ÜBERLEBENDER NEBENNIEREN EINER PATIENTIN MIT CUSHING- UND EINER PATIENTIN MIT CONN-SYNDROM

1963 ◽  
Vol 43 (3) ◽  
pp. 419-429 ◽  
Author(s):  
H. Schriefers ◽  
J. M. Bayer ◽  
M. Pittel
Keyword(s):  
Adrenal Gland ◽  
Adrenal Cortex ◽  
Zona Glomerulosa ◽  
Secretion Rate ◽  
Zona Fasciculata ◽  
Conn’S Syndrome ◽  
Adrenal Cortical Adenoma ◽  
Aldosterone Production ◽  
The Right

ABSTRACT In vitro perfusion experiments were carried out with adrenal glands surgically removed from a patient with Cushing's syndrome (hyperplasia of the adrenal cortex) and a patient with Conn's syndrome (adrenal cortical adenoma). From the perfusates the following steroids were extracted, estimated and identified: cortisol, corticosterone, 11β-hydroxyandrostenedione, cortisone and aldosterone. The secretion capacities of the right Cushing adrenal and of the adrenal gland bearing the adenoma were compared with each other. In both adrenals cortisol was the main secretion product and the secretion rates of aldosterone were lowest and practically equal. The Cushing adrenal differed from the adrenal gland with the adenoma in its higher secretion rate of all investigated steroids except aldosterone, in its higher cortisol/aldosterone ratio and in its response to the administration of ACTH. To this stimulus the aldosterone production of the Cushing adrenal reacted in the same rate as the cortisol release. The adrenal gland with the adenoma of the patient with Conn's syndrome had only a relatively higher aldosterone secretion rate in respect to its lower cortisol production (lower cortisol/aldosterone ratio). The total preparation consisting of the adrenal with the adenoma responded neither to ACTH nor to hypertensin. The missing response of the adrenal cortex not including the tumor to ACTH is explained by the structural change in the sense of the so called regressive transformation (small zona fasciculata with relative large zona glomerulosa and reticularis) which was found in our case. Dehydroepiandrosterone was demonstrable in none of the perfusate extracts even under the condition where the left adrenal of the Cushing patient was perfused with added 17α-hydroxy-pregnenolone.

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