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Biomedical subjects

W Sutanto

Publications and source records attributed to W Sutanto.

At least 37 records · Page 2Linked to original sources
PubMed1991

Regulation of vasopressin messenger RNA levels in the small cell lung carcinoma cell line GLC-8: interactions between glucocorticoids and second messengers.

The role of glucocorticoids and second messenger systems in the regulation of the vasopressin (VP) gene was studied in the human small cell lung carcinoma cell line GLC-8. Small cell lung carcinoma GLC-8 cells express VP mRNA and contain both glucocorticoid and mineralocorticoid receptors. Treatment with the synthetic glucocorticoid dexamethasone when added alone at 10(-8) M had no effect on the VP mRNA level and decreased the level by 30% at 10(-6) M. However, the effect of dexamethasone changed to positive when cells were simultaneously treated with cAMP-enhancing agents. VP mRNA levels, which were elevated by 1.5- to 2-fold by the cAMP-enhancing agents alone, increased a further 1.5- to 3-fold by dexamethasone. Thus, the combined effect of dexamethasone and cAMP stimulation was a 3- to 7.5-fold increase in VP mRNA levels. Long term treatment with the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) reduced the VP mRNA level by 75%. The TPA-suppressed VP mRNA levels could be up-regulated about 6-fold by simultaneous treatment with 8-bromo-cAMP. Dexamethasone did not alter the TPA-suppressed VP mRNA levels. These results indicate that both cAMP and protein kinase-C pathways as well as glucocorticoid receptors are involved in the regulation of VP mRNA levels and that these factors interact. This leads to a negative or positive response of VP gene expression to glucocorticoids in a state-dependent manner. The interactions may be of significance in a physiological context and relate to the different regulation of VP-expressing systems in the brain.

1-Methyl-3-isobutylxanthine↗
PubMed1991

Plasticity and function of brain corticosteroid receptors during aging.

The actions of adrenal corticosteroids on the brain are critical for the maintenance of homeostasis. These actions are mediated by two receptors: mineralocorticoid (MRs) and glucocorticoid receptors (GRs), which are co-localized in hippocampal neurons. Our research has shown that MR- and GR-mediated effects restore disturbances in homeostasis, but they do so via an opposite mode of action. The MR-mediated effect increases cellular responsiveness to excitatory stimuli, controls the sensitivity of the stress response system and affects behavioural strategies. GR activation suppresses excitability raised by excitatory stimuli, controls feedback action and promotes information storage. These observations have led to the concept that a change in balance of hippocampal MRs and GRs affects the set point of homeostatic control, which may change the susceptibility to stress. Aging is defined as a period with decreased ability to maintain homeostasis, increased lability of the hypothalamic-pituitary-adrenal (HPA) axis following stress, and impaired behavioural adaptation. The present contribution examines age-induced changes in HPA activity in the rat in the context of hippocampal MRs and GRs, and structural features of the hippocampal neurons. The new data demonstrate that depending on the individual animal and the rat strain; 1. The level of ACTH, or corticosterone, or both is increased; 2. Binding capacity of MR is decreased, but that of GR is unchanged, decreased or resistant to down-regulation; the decrease in MRs is consistent with increased stress responsiveness of the HPA axis, and 3. The hippocampal structure shows regional differences in cellular degeneration during over- and underexposure to corticosteroids and stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1990

Corticosteroids and the brain.

Mineralocorticoid (MR) and glucocorticoid receptors (GR) are expressed in the central nervous system. Radioligand binding studies, autoradiography, immunocytochemistry and in situ hybridization have shown that MR and GR are found in abundance in neurons of the limbic system (hippocampus), a structure involved in mood, affect and subtle control of the hypothalamic-pituitary-adrenal (HPA) axis. In the hippocampus MR binds corticosterone (CORT) as well as aldosterone (ALDO) with high affinity. MR seems mainly occupied by CORT in the face of its 2-3 order higher circulating concentration. GR binds CORT with a 6-10-fold lower affinity. MR and GR gene expression, as well as the native receptor proteins, seem to be controlled in a coordinative manner. When GR is down-regulated by excess homologous steroid, MR appears to be increased. Down regulation of MR reduces GR as well. MR and GR display a differential ontogenetic pattern. Ontogeny, particularly that of GR, can be permanently influenced when animals are exposed during the first post-natal week of maternal deprivation, handling, CORT or ACTH1-24 injections. These MR and GR changes persist into senescence and have been proposed to result in altered CORT responsiveness, stress regulation, behavioural adaptation and brain aging.

Adrenal Cortex Hormones↗
PubMed1990

Ontogeny of mineralocorticoid (type 1) receptors in brain and pituitary: an in vivo autoradiographical study.

The ontogeny of high affinity [3H]corticosterone uptake and retention in brain and pituitary of 24-h adrenalectomized rats was examined using autoradiography of in vivo labeled brain sections. Our data indicate: (1) There is specific uptake of radiolabeled steroid in both brain and pituitary already at 2 days of age, following administration of a tracer (2 microCi/g body wt.) dose of [3H]corticosterone. This uptake is maximum around 4-8 days of age and decreases towards adult values around postnatal day 16. (2) High affinity uptake, at least in the brain, probably represents mostly binding to the mineralocorticoid receptor (MR) and not to the glucocorticoid receptor (GR), as it was not displaced by an excess dose of a GR antagonist, RU 38486, and its location in the hippocampus resembled that of MRs in the adult animal. The tracer amounts of [3H]corticosterone circulating after injection in the rat pups resulted in steroid levels comparable to basal levels of non-adrenalectomized animals of equivalent age. Thus, MRs may be the receptors mainly responsible for mediating physiological effects of glucocorticoids during early ontogeny.

Aging↗
PubMed1990

Central action of adrenal steroids during stress and adaptation.

Corticosteroids interact with receptors in the central nervous system. These receptors display heterogeneity and can be distinguished as corticosterone- and aldosterone-binding mineralocorticoid receptors and dexamethasone-binding glucocorticoid receptors. Ligand specificity of mineralocorticoid receptors for either corticosterone or aldosterone seems to be determined by co-localized transcortin and the enzyme, 11 beta-hydroxysteroid dehydrogenase. Aldosterone-selective mineralocorticoid receptors appear to be present in the circumventricular organs and the AV3V region of the hypothalamus and mediate behavior that is driven by salt appetite. Highest concentrations of mineralocorticoid receptors are found in neurons of the hippocampus. These limbic mineralocorticoid receptor sites mediate tonic influences of corticosterone on brain processes. Glucocorticoid receptors bind corticosterone with a tenfold lower affinity than do mineralocorticoid receptors, and are widely distributed in neuronal and glial cells of the brain. Glucocorticoid receptors are involved in the termination of the stress response (negative feedback). Studies involving measurement of glucocorticoid receptor mRNA and binding sites have revealed that glucocorticoid receptors are subject to autoregulation. After ADX, glucocorticoid receptor concentration increases, but is reduced after chronic stress, chronic administration of glucocorticoids, and at senescence. A diminished glucocorticoid receptor concentration may compromise the negative feedback action exerted by glucocorticoids after stress. After ADX, mineralocorticoid receptor binding is acutely up-regulated and reaches its maximum between 7 and 24 hours post-ADX. Mineralocorticoid receptor mRNA level shows a transient increase following ADX. Long-term ADX has no effect on the mineralocorticoid receptor concentration, but, interestingly, chronic dexamethasone treatment results in an up-regulation of mineralocorticoid receptors. Mineralocorticoid receptor level is decreased at senescence, but this age-related decrement can be reversed by chronic treatment with the ACTH4-9 analog, ORG 2766. Functionally, mineralocorticoid receptors and glucocorticoid receptors are involved in different aspects of the organization of the stress response, and in conjunction they control the stress responsiveness of the animal.

Adaptation, Psychological↗
PubMed1989

On the role of brain mineralocorticoid (type I) and glucocorticoid (type II) receptors in neuroendocrine regulation.

Administrations of the glucocorticoid receptor antagonist (anti-glucocorticoid, RU38486) and the mineralocorticoid antagonist (anti-mineralocorticoid, RU28318) followed by frequent, sequential blood sampling were employed to investigate the possible role the brain mineralocorticoid receptor (MR, type I) and glucocorticoid receptor (GR, type II) have in the regulation of basal and stress-induced adrenocortical secretion in the rat. The anti-mineralocorticoid and anti-glucocorticoid were administered subcutaneously (s.c.) at doses of 2.5 mg and 1.0 mg/100 g body weight, respectively. Both antagonists were also given intracerebroventricularly (i.c.v.) at a dose of 100 ng/rat. Under basal non-stressed conditions (at the diurnal trough in the morning), injections of either saline, anti-glucocorticoid (s.c. or i.c.v.) or anti-mineralocorticoid (s.c.) did not have effect on the plasma corticosterone level. The anti-mineralocorticoid given intracerebroventricularly, however, caused an elevation of plasma corticosterone up to 60 min after the injection. Exposure of the rats to a novel environment resulted in a large increase in the plasma corticosterone level, which was slightly reduced in the rats treated with the anti-glucocorticoid. In vehicle-treated rats, the level returned to basal values at 90 min, while in the anti-glucocorticoid- and anti-mineralocorticoid-treated groups, it remained elevated for prolonged periods. The present study thus shows that (1) the anti-glucocorticoid RU38486 via the brain GR has no effect on the basal plasma corticosterone level in the morning but interferes with a glucocorticoid negative feedback following stress and (2) the anti-mineralocorticoid RU28318 via the brain MR elevates the basal plasma corticosterone level and enhances adrenocortical secretion following stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Ontogeny of type I and type II corticosteroid receptors in the rat hippocampus.

The ontogeny of the corticoid receptors in the rat hippocampus was examined by in vitro [3H]corticosterone (CORT) binding to soluble molecules in the cytosol, using the selective Type II glucocorticoid agonist, RU 28362, to discriminate between Type I and Type II receptor sites. Type I receptors were undetectable until 8 days after birth. From this age on, the receptor showed adult characteristics for both the binding capacity (Bmax) and affinity (Kd). The Type II receptor concentration increased gradually over the observed period; however, at 3 weeks of age concentrations were still only about 65% those found in adults. The binding affinity of Type II to CORT was high during the first week of life but decreased thereafter towards adult value. These data thus suggest clear distinctions in the developmental patterns of Type I and Type II receptors for corticosteroids in the rat.

Aging↗
PubMed1988

A correlative study of RU38486 biopotency and competition with [3H]dexamethasone for receptors in the rat central nervous system.

Dexamethasone inhibitory action on the release of adrenocorticotrophin has been studied using in vitro anterior pituitary preparations. This inhibition is reversed when the animal is given the antiglucocorticoid compound RU38486 simultaneously with dexamethasone. RU38486 acts at the receptor level and in the cytosolic binding study, it competes with [3H]dexamethasone for the binding sites in pituitary. Such competition is even more pronounced in hypothalamus and hippocampus, indicating that RU38486 also exert its antagonistic action at these sites.

Adrenalectomy↗
PubMed1988

Corticosteroid receptor analyses in rat and hamster brains reveal species specificity in the type I and type II receptors.

In vitro cytosol binding, receptor autoradiography with radiolabelled corticosteroid analogs, and immunocytochemistry with monoclonal antibodies have revealed the presence of two receptor systems for corticosteroids in rat and hamster brains. The type I receptor is found mainly in the hippocampal region, and in the hamster it binds cortisol (F) and corticosterone (B) with similar affinity while in the rat (a species which unlike the hamster secretes solely B) the type I receptor shows high affinity to B and not to F. The type II receptor is more widely distributed in the brain and it binds to F (hamster) or B (rat) with affinity 4-6-fold lower than to the type I. in vivo, the hamster type I and II retain F much more than B while those in the rat show the opposite. In conclusion, the present study clearly indicates species-specificity in type I and type II receptor systems in these animals. Furthermore, the type I receptor displays in vivo stringent preference for retention of the animal's predominantly circulating corticosteroid (F in hamster, in B in rat).

Adrenalectomy↗
PubMed1988

ZK91587: a novel synthetic antimineralocorticoid displays high affinity for corticosterone (type I) receptors in the rat hippocampus.

In vitro cytosol binding assays have shown the properties of binding of a novel steroid, ZK91587 (15 beta, 16 beta-methylene-mexrenone) in the brain of rats. Scatchard and Woolf analyses of the binding data reveal the binding of [3H] ZK91587 to the total hippocampal corticosteroid receptor sites with high affinity (Kd 1.9 nM), and low capacity (Bmax 17.3 fmol/mg protein). When 100-fold excess RU28362 was included simultaneously with [3H] ZK91587, the labelled steroid binds with the same affinity (Kd 1.8 nM) and capacity (Bmax 15.5 fmol/mg protein). Relative binding affinities (RBA) of various steroids for the Type I or Type II corticosteroid receptor in these animals are: Type I: ZK91587 = corticosterone (B) greater than cortisol (F); Type II: B greater than F much greater than ZK91587. In the binding kinetic study, ZK91587 has a high association rate of binding in the rat (20.0 x 10(7) M-1 min-1). The steroid dissociates following a one slope pattern (t 1/2 30 h), indicating, the present data demonstrate that in the rat hippocampus, ZK91587 binds specifically to the Type I (corticosterone-preferring/mineralocorticoid-like) receptor.

Animals↗
PubMed1988

Species-specific topography of corticosteroid receptor types in rat and hamster brain.

In vivo and in vitro autoradiography with radiolabeled corticosteroid analogs as well as immunocytochemistry with monoclonal antibodies raised against the rat liver glucocorticoid receptor were used to determine the presence and the topography of two corticosteroid receptor systems (type I and type II) in hamster and rat brains. In the rat, the in vivo autoradiograms clearly revealed the retention by the type I receptor of tracer amount of [3H]corticosterone, primarily in the CA1 and CA2 cell field, dentate gyrus and lateral septum. In the hamster, tracer doses of [3H]cortisol were retained not only in the CA1, CA2, dentate gyrus and lateral septum, but also at high level in the CA3 and CA4 areas. In both species, immunocytochemistry showed the widespread distribution of the type II receptor sites in areas such as the hippocampus, lateral septum, hypothalamus (particularly in the paraventricular nucleus), thalamus and cortex (these results were also reflected in the in vitro autoradiography). Strong cell nuclear glucocorticoid immunoreactivity (type II-IR) was observed in the CA1 and CA2 (as well as CA3 and CA4 in the hamster) pyramidal neurons. In the hippocampus of intact animals, type II-IR was seen in the neuronal cell nuclei. Adrenalectomy caused a depletion of the type II-IR signal from the cell nucleus, which returned 1 h following subcutaneous administration of RU 28362 to adrenalectomized animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Long-lasting glucocorticoid suppression of opioid-induced antinociception.

The antinociceptive effect of morphine (5 mg/kg body weight i.p.) in rats subjected to various experimental manipulations of the pituitary-adrenocortical system was studied. The absence of adrenal steroids increased the sensitivity to morphine. The following findings suggest that glucocorticosteroids have a long-lasting influence on opioid-induced antinociception, even when the steroids have been removed by adrenalectomy. First, when rats were adrenalectomized in the morning under basal conditions of pituitary-adrenocortical activity (plasma corticosterone level less than 1 microgram %), the subsequent hypersensitivity to morphine-induced antinociception following adrenalectomy either in the morning or in the evening persisted for at least 2 weeks. Second, exposure to a novel environmental (stress of a new cage) or administration of corticosterone (10 mg/kg body weight s.c.) prior to morning adrenalectomy decreased the sensitivity to morphine measured 1 week later. Third, RU 38486, a glucocorticoid antagonist, injected in the lateral cerebral ventricle prior to the evening adrenalectomy increased subsequent morphine antinociception. In attempts to understand the long-term effect on morphine antinociception, the opioid receptor sites were quantified by an in vivo procedure. Quantitative autoradiography of binding sites labeled after intravenous administration of a tracer dose of [3H]-diprenorphine showed a decrease in retention of the labeled opioid in cortical and midbrain regions of rats adrenalectomized in the evening when compared with rats operated in the morning.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1987

Species-specificity of corticosteroid receptors in hamster and rat brains.

In vitro cytosolic receptor binding assays and autoradiographical procedures have shown the localization and properties of two corticoid receptor types in the brain of the rat, a species in which corticosterone (B) is the predominant circulating glucocorticoid. The present study was designed to examine the localization, heterogeneity, and binding specificity of corticosteroid receptors in the brain of the hamster, a species which secretes B and cortisol (F), the latter being the predominantly circulating form. Our results show that two corticoid receptor systems can also be distinguished in the hamster brain. The type I receptor has an almost exclusive localization in the hippocampal region and the amounts measured in hypothalamic or whole brain (without the hippocampus) were negligible. The type II receptor, on the other hand, has a wider distribution in the brain. Scatchard and Woolf analyses of the binding data revealed that the hamster type I receptor has similar affinity to both F and B [dissociation constant (Kd) 0.9 nM]. In contrast the rat type I binds with higher affinity to B (Kd, 0.9 nM) than to F (Kd, 2.2 nM). The hamster type II binds to F with much higher affinity (Kd, 2.9 nM) than does the rat type II to F (Kd, 20.1 nM). This was similarly observed, although less pronounced in the binding of the hamster type II and the rat type II to B (Kd, 0.5 and 3.9 nM, respectively). Analysis of relative binding affinity of each receptor type gave the following results. Hamster type I: F greater than B much greater than aldosterone (ALDO) greater than dexamethasone (DEX); rat type I: B greater than F greater than ALDO greater than DEX; hamster type II: B greater than DEX greater than F much greater than ALDO; rat type II: DEX greater than B much greater than F much greater than ALDO. Graded doses of F or B given sc to adrenalectomized animals result in differential occupancy of the two receptor systems. In hamster, 1.0 microgram F vs. 1.0 mg B/100 g BW is required to occupy 80% of type I site. The rat shows the opposite (1.0 microgram B vs. 5.0 to 10.0 mg F/100 g BW to occupy type I to the same extent). The hamster type II is 80-90% occupied by an equal dose of F or B (1.0 mg/100 g BW) whereas in the rat, F at 5-10 mg/100 g BW (doses 5-10 times that of B) is required to achieve this same occupancy. This data demonstrate the

Adrenal Cortex Hormones↗
PubMed1986

Effects of 6-hydroxydopamine on the hypothalamo-pituitary-adrenocortical axis.

Female rats were treated with two intraventricular injections each of 350 micrograms 6-hydroxydopamine (6-OHDA) and used for experiment 4 or 14 days later. The response to laparotomy, as assessed by subsequent in vitro corticosterone release, was unaffected by the drug, but that to the smaller stress of a skin cut was significantly reduced. Both fast and delayed feedback responses to corticosterone administration were still evident in 6-OHDA-treated animals. When determined 14 days after treatment, hypothalamic concentrations of epinephrine (E) and norepinephrine (NE) were reduced by 46 and 84%, respectively. There was no significant change in content of immunoreactive corticotropin-releasing factor (CRF-41). The acetylcholine-stimulated release of CRF bioactivity from control hypothalami incubated in vitro was significantly inhibited by E or NE, with E being at least 10 times more potent on a molar basis. This effect of NE was enhanced in hypothalami removed from 6-OHDA-treated rats, complete inhibition of acetylcholine-stimulated release of CRF being produced by 0.6 nM NE, as opposed to 6.0 nM for untreated controls. At the level of the anterior pituitary gland, tissue content of adrenocorticotropin (ACTH) was unaffected by treatment, but that of luteinizing hormone (LH) in the same tissues was significantly increased. The corticotrophic response of fragments of the gland incubated or perifused in vitro to hypothalamic extract, CRF-41, arginine vasopressin or E was reduced. In contrast, the response of the tissue to gonadotropin-releasing hormone (GnRH) added in vitro was not significantly affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1986

The combination of 17 alpha-hydroxyprogesterone and 11-epicortisol prevents the delayed feedback effect of natural and synthetic glucocorticoids.

Subcutaneous injection of 400 micrograms/100 g body weight of corticosterone (B) 2 h previously in male rats prevented the stress response, as assessed by the ability of adrenal glands removed from these animals to produce endogenous B. Two injections of a combination of 17 alpha-hydroxyprogesterone and 11-epicortisol, the first given 30 min before and the second with the B, were able to block this inhibitory effect on the stress response. Neither of the steroids alone was effective in this regard. The combination was also effective against the early delayed feedback effects of 400 micrograms/100 g body weight cortisol, prednisolone or beclomethasone dipropionate in the same system. The minimum effective dose for reversal of feedback by B or beclomethasone dipropionate (2 mg/100 g body weight of each antagonist) was lower than that required for the same effect against prednisolone or cortisol (5 mg/100 g body weight). Previous injection of B also abolished the ability of anterior pituitary gland fragments to respond to corticotropin-releasing factors (CRFs) added in vitro, an effect which was not abolished by the injection of the combination of putative antagonistic steroids. From experiments designed to measure the ability of 17 alpha-hydroxyprogesterone and 11-epicortisol to compete with 3H-corticosterone in binding to macromolecular components in hypothalamic, hippocampal and pituitary cytosolic preparations, it was deduced that the competition seen in the hypothalamic and hippocampal, rather than the pituitary, preparations was in better accord with the effect seen on the stress response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗