Showing papers by "Allan Munck published in 1984"
TL;DR: It is proposed that stress-induced increases in glucocorticoid levels protect not against the source of stress itself but rather against the body's normal reactions to stress, preventing those reactions from overshooting and themselves threatening homeostasis.
Abstract: Introduction and Background Modern glucocorticoid endocrinology is a colorful, richly varied, but formless discipline—a profusion of cellular, physiological and pharmacological effects, seemingly unrelated through any central hormonal function. A current list of glucocorticoid effects might include such disparate items as stimulation of hepatic gluconeogenesis, inhibition of glucose uptake by peripheral tissues, suppression of inflammation, enhanced excretion of a water load, induction in various cells of tryptophan oxygenase and glutamine synthetase, suppression of numerous immune reactions, inhibition of secretion of several hormones and neuropeptides, and inhibition of activity of plasminogen activator and other neutral proteinases. Judging from recent writings on glucocorticoid physiology, an item that might be low on the list or missing altogether is “increased resistance to stress”.
3,050 citations
TL;DR: Results provide the first clear evidence that sulfhydryl-modifying reagents inhibit the binding of activated dexamethasone-receptor complexes to DNA-cellulose and suggest that sulfHydryl groups may be located in or near the DNA binding domain of the rat thymus glucocorticoid -receptor complex.
Abstract: Glucocorticoid -receptor complexes from intact rat thymus cells incubated with [3H]dexamethasone at 0 degree C are in the nonactivated form and do not bind to DNA-cellulose. Upon being warmed, they are transformed to activated complexes that bind to DNA-cellulose at 0 degree C. We have found that treatment of dexamethasone-receptor complexes with the sulfhydryl-modifying reagents methyl methanethiosulfonate ( MMTS ) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), either before or after the warming, inhibits subsequent binding to DNA-cellulose. The effects of these reagents can be reversed at 0 degree C by dithioerythritol and other sulfhydryl-containing compounds. These results provide the first clear evidence that sulfhydryl-modifying reagents inhibit the binding of activated dexamethasone-receptor complexes to DNA-cellulose and suggest that sulfhydryl groups may be located in or near the DNA binding domain of the rat thymus glucocorticoid-receptor complex. Furthermore, addition of dithioerythritol at 0 degree C to nonactivated receptor complexes that have been treated with MMTS or DTNB produces a substantial increase in the capacity of these complexes to bind to DNA-cellulose, raising the possibility that sulfhydryl groups may be associated with a region on the receptor that plays a critical role in the activation process.
74 citations
TL;DR: Purified receptor, covalently labeled with [3H]dexamethasone to the sulfhydryl associated with the steroid binding domain, was able to bind to DSCT matrix, providing evidence for distinct sulfHydryl groups associated withThe steroid and DNA binding domains.
Abstract: We have found that nonactivated and activated forms of the rat thymus glucocorticoid-receptor complex (GRC) will react with reactive sulfhydryl matrices to form covalently immobilized complexes that can subsequently be eluted with reducing agents. The interaction of GRCs with these matrices depends on the nature of both the immobilized sulfhydryl group and the type of leaving group attached. One matrix, agarose CL-4B-diaminoethyl-succinyl-thioethylamine-2-thiopyridyl+ ++ (DSTT), binds total receptor-bound steroid. A second matrix, agarose CL-4B-diaminoethyl-succinyl-cysteinyl-2-thiobenzoic acid (DSCT), binds activated but not nonactivated complexes. The reaction of activated complexes with the DSCT matrix is apparently through a sulfhydryl group located near the DNA binding domain, as soluble DNA interferes with the reaction. This sulfhydryl group(s) appears to be located in a portion of the GRC that is resistant to degradation, since proteolytic digestion of activated GRC to a point where DNA binding is lost results in only a moderate decrease in binding with the DSCT matrix. Purified receptor, covalently labeled with [3H]dexamethasone to the sulfhydryl associated with the steroid binding domain, was able to bind to DSCT matrix, providing evidence for distinct sulfhydryl groups associated with the steroid and DNA binding domains.
48 citations
Journal Article•
TL;DR: These findings indicate the presence of an endogenous factor, present in CLL but lacking in ANLL cells, which is capable of stabilizing cytosolic complexes, and suggest that lability may in part be related to the state or direction of differentiation of the leukemic cells.
Abstract: Glucocorticoid-receptor complexes in cytoplasm from normal lymphoid and leukemia cells incubated with glucocorticoid can be resolved into three different components, activated, nonactivated, and mero-receptor complexes, in relative amounts, dependent on the conditions to which the cells or cytosols are exposed. Recently, we reported that cytosols of acute nonlymphocytic leukemia (ANLL) cells contained high levels of meroreceptor complexes relative to those of chronic lymphocytic leukemia (CLL) or normal lymphoid cells. In the present study, we examined the cause for the lability of cytosolic complexes of ANLL cells. Mero-receptor accumulated rapidly in ANLL cytosols in a time-dependent fashion. The accumulation was most rapid in cytosols which contained activated receptor complexes, but it also occurred in cytosols containing only nonactivated receptor forms. Molybdate (20 mm) slowed but did not prevent the conversion to mero-receptor. Cytosols of ANLL specimens of the M4 French-American-British class (with monocytoid differentiation properties), in general, contained more stable complexes than did specimens of the M1 to M3 French-American-British classes (primarily myelocytic differentiation) suggesting that lability may in part be related to the state or direction of differentiation of the leukemic cells. In keeping with this hypothesis, cytosols of polymorphonuclear cells isolated from normal blood were much more labile than were those of monocytes. Mixing experiments with ANLL and CLL cells showed that the lability of ANLL complexes is not due simply to a higher content of proteolytic enzymes in these cells, because addition of ANLL cells or cytosols to CLL specimens did not result in increased mero-receptor. To the contrary, addition of CLL cells to ANLL specimens greatly stabilized the cytosolic complexes. These findings indicate the presence of an endogenous factor, present in CLL but lacking in ANLL cells, which is capable of stabilizing cytosolic complexes.
17 citations
TL;DR: It is shown that nonactivated rat thymus complexes in cytosols with molybdate and 400 M KCl have Rs = 8 nm, which can be accounted for quantitatively with a simple cyclic (irreversible) model in which the dissociation rate constant of the steroid plays a key role.
10 citations
TL;DR: It is proposed that the stabilizing factor from WEHI-7 cytosol is an endogenous inhibitor of the protease(s) responsible for mero-receptor formation, and thus appears distinct from the previously described endogenous glucocorticoid receptor stabilization factor responsible for stabilization of thymocyte receptor binding capacity.
7 citations