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J Fukata

Publications and source records attributed to J Fukata.

At least 37 records · Page 2Linked to original sources
PubMed1993

Purification and characterization of new anti-adrenocorticotropin rabbit neutrophil peptides (defensins).

Neutrophil peptides (NPs, defensins), which consist of approximately 30 amino acids with a highly conserved backbone of six Cys residues, possess several biological activities, such as antimicrobial, antiviral, cytotoxic, and anti-adrenocorticotropin (corticostatic) activity in vitro. In the rabbit, six NPs, i.e., NP-1, -2, -3A, -3B, -4, and -5, have been isolated, among them, NP-3A has the most potent corticostatic activity, which involves the inhibition of adrenocorticotropin-stimulated corticosterone synthesis in adrenal cells. Using a sensitive radioimmunoassay for NP-3A and reverse-phase HPLC, we found a novel component in rabbit tissue extracts with NP-3A-like immuno-reactivity. We further purified and characterized the component and found two novel peptides. One of these peptides, designated NP-6, has an amino acid sequence identical to that of NP-3A except for three amino acids, i.e. Leu11, Phe13, and Gln15, in the central portion of the sequence. The other has a sequence corresponding to that of NP-6 except that the N-terminal Gly was deleted and is thus named des-G1-NP-6. Using chemically synthesized NP-6 and des-G1-NP-6, we measured their putative corticostatic activities by a dispersed rat adrenal cell bioassay. NP-6 showed corticostatic activity comparable to that of NP-3A while des-G1-NP-6 showed weak activity. These findings are also compatible with the notion that the N-terminal Gly, but not the central portion, is important for the anti-adrenocorticotropin activity of the NPs.

Adrenocorticotropic Hormone↗
PubMed1993

Inhibition of PMA-induced, LFA-1-dependent lymphocyte aggregation by ADP ribosylation of the small molecular weight GTP binding protein, rho.

Botulinum C3 exoenzyme specifically ADP-ribosylates a group of ras-related small molecular weight GTP-binding proteins, rho, and inhibits their biological activity. Using this enzyme, we examined the function of rho in PMA-induced activation of lymphocyte function-associated antigen-1 (LFA-1) in a B lymphoblastoid cell line, JY. Northern blot analysis revealed that among the three rho genes, rhoA mRNA was predominantly expressed in JY cells. Consistently, only one [32P]ADP-ribosylated band was found when the lysate of the cells was subjected to ADP ribosylation by C3 exoenzyme. When the cells were cultured with C3 exoenzyme, this substrate was ADP-ribosylated in situ in a time- and concentration-dependent manner. Concomitant with this ADP ribosylation, PMA-induced LFA-1/intercellular adhesion molecule (ICAM)-1-dependent aggregation of JY cells was inhibited. This inhibition was blocked by prior treatment of the enzyme with an anti-C3 monoclonal antibody, and overcome by stimulation with higher concentrations of PMA. The C3 exoenzyme-induced inhibition was not affected by shaking of the cell suspension, while inhibition of aggregation by cytochalasin B was abolished by this procedure, suggesting that the inhibitory effect of the C3 exoenzyme treatment was not due to decrease in cell motility. The C3 exoenzyme treatment affected neither protein phosphorylation in JY cells before and after PMA stimulation, nor affected surface expression of LFA-1 and ICAM-1. These results suggest that rhoA protein works downstream of protein kinase C activation linking PMA stimulation to LFA-1 activation and aggregation in JY cells.

ADP Ribose Transferases↗
PubMed1993

Bacterial lipopolysaccharide-induced expression of interleukin-6 messenger ribonucleic acid in the rat hypothalamus, pituitary, adrenal gland, and spleen.

Whereas the stimulatory effect of interleukin-6 (IL-6) on the hypothalamic-pituitary-adrenal (HPA) axis is well established, its mode of action in this axis has yet to be fully elucidated. To further study the role of IL-6 in the HPA axis, we compared the expression of IL-6 messenger RNA (mRNA) in the rat hypothalamus, pituitary, and adrenal gland with that in the spleen after ip or intracerebroventricular (icv) administration of bacterial lipopolysaccharide (LPS). After either ip or icv administration, LPS induced the expression of IL-6 mRNA, which consists of 1.2 kilobases (kb) and 2.4 kb subclasses, in all these tissues of the HPA axis as well as in the spleen. Although we used 100 times less amount of LPS for the icv administration than that used for ip LPS, plasma ACTH levels in both the conditions rapidly reached comparable levels. This icv dose induced IL-6 mRNA expression in the hypothalamus faster than ip dose but also stimulated IL-6 mRNA expression in the hypothalamus, pituitary, and adrenal gland more effectively and smoothly than the ip LPS dose did. Northern blot analysis revealed that in the hypothalamus, pituitary, and adrenals, the predominant subclass of IL-6 mRNA was not 1.2 kb but 2.4 kb. In contrast, this subclass was the minor component in the spleen induced under the same circumstances. These findings indicate that IL-6-synthesizing cells in the HPA axis differ in character from those in the spleen, and that LPS applied in vivo may modulate IL-6 expression in these cells directly and/or indirectly through secondarily activated functions in the neuronal or endocrine systems.

Animals↗
PubMed1993

Human corticotropin-releasing hormone (hCRH) test: sex and age differences in plasma ACTH and cortisol responses and their reproducibility in healthy adults.

The effectiveness and safety of MCI-028, a synthetic human corticotropin-releasing hormone (hCRH), as a diagnostic drug were examined in 65 healthy male and 24 healthy female adult volunteers. Mean maximum concentrations of plasma ACTH and cortisol after intravenous administration of 100 micrograms of MCI-028 were 3.0 and 2.0 times their basal concentrations, respectively, and there were no significant age or sex differences in the responses. Good reproducibility was observed in the responses in 59 male subjects who received a second administration after 1 to 2 weeks. Although slight adverse reactions such as mild and transient hot flushing were observed, these were not serious.

Adrenal Cortex Function Tests↗
PubMed1993

Evaluation of hypothalamo-pituitary-adrenocortical function in children by human corticotropin-releasing hormone (MCI-028) test.

A dose of 1.5 micrograms/kg of MCI-028, human corticotropin-releasing hormone (hCRH), was administered intravenously to 38 children with non-endocrine short stature with normal function in the hypothalamo-pituitary-adrenocortical axis and to 71 children with a disorder in the same axis. Blood levels of adrenocorticotropic hormone (ACTH) and cortisol were determined to evaluate the axis. The 95% confidence limits of peak responses of ACTH and cortisol in non-endocrine short stature were between 17.2 and 135.3 pg/ml, and between 13.1 and 35.6 micrograms/dl, respectively, and were used as standards for children. When compared with these standards, the hormonal responses in children with various disorders in the hypothalamo-pituitary-adrenocortical axis were as follows: in two children with Cushing's syndrome caused by adrenal tumor, ACTH values were decreased and were not responsive to hCRH, while cortisol values, though within the normal limit, were not responsive; in children with primary adrenal insufficiency or congenital adrenal hyperplasia, cortisol values were decreased and not responsive, whereas ACTH values tended to be increased and ACTH response high except for 21 alpha-hydroxylase deficiency of congenital adrenal hyperplasia. In two cases of pituitary dwarfism complicated with ACTH deficiency, both ACTH and cortisol values were decreased and poorly responsive; and in children who were receiving glucocorticoid, both ACTH and cortisol values tended to be decreased and to respond poorly to hCRH. As for side effects, hot flushing was observed among 8.0% of the subjects after administration of hCRH. But this symptom was not severe and no other side effects of clinical importance were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Human corticotropin-releasing hormone test in patients with hypothalamo-pituitary-adrenocortical disorders.

To assess the diagnostic usefulness of a synthetic human corticotropin-releasing hormone (CRH) formulation (Code No. MCI-028), we administered 100 micrograms of the peptide intravenously to 183 patients with hypothalamo-pituitary-adrenocortical (HPA) disorders, and obtained the following findings. Among the 183 patients, data from 125 patients were suitable for analyzing the effects of the test. In patients with Cushing's disease, high plasma adrenocorticotropic hormone (ACTH) and cortisol levels increased further in response to MCI-028, while in patients with adrenal Cushing's syndrome, low ACTH and high cortisol values remained unchanged. In patients with pituitary-type hypopituitarism or isolated ACTH deficiency, low ACTH and cortisol levels responded poorly or insignificantly to MCI-028, whereas those with hypothalamic hypopituitarism showed delayed and considerable degree of responses of plasma ACTH and little increase in plasma cortisol levels. In Addison's disease, high plasma ACTH increased further in response to MCI-028, but low cortisol levels did not change. In patients with Cushing's syndrome soon after successful surgical treatment, plasma ACTH responsiveness was low or different depending on the clinical course of the patient. Patients treated with high doses of glucocorticoids for non-endocrine diseases tended to show impaired ACTH and cortisol responsiveness to MCI-028. Side effects, including the transient flushing which was observed most frequently in this study, did not cause any clinical problems.

Adolescent↗
PubMed1993

Pro-opiomelanocortin messenger RNA levels in anterior pituitaries of female Wistar fatty rats.

We have studied pro-opiomelanocortin (POMC) gene expression by quantifying the POMC mRNA contents in anterior pituitaries of female Wistar fatty rats, a strain obtained by transfer of the fa gene in Zucker rat to Wistar Kyoto rat, in an attempt to understand the role of ACTH synthesis in altered ACTH and corticosterone secretion in these rats. Five- and 12-week-old female Wistar fatty rats and their lean littermates were examined. Plasma ACTH levels were significantly higher in fatty rats than in lean rats (5 weeks: 114.5 +/- 17.5 pg/ml vs. 54.3 +/- 12.4 pg/ml; 12 weeks: 83.8 +/- 12.3 pg/ml vs. 51.7 +/- 6.8 pg/ml; P < 0.01). There was no significant difference between 5-week-old fatty rats and lean rats in POMC mRNA contents nor in POMC/beta-actin ratios in anterior pituitaries. Twelve-week-old fatty rats, however, had significantly higher POMC mRNA contents and also higher POMC/beta-actin ratios in anterior pituitaries than those in lean littermates (P < 0.01, approximately three-fold difference between lean and obese rats). These data suggest that the difference in POMC mRNA contents between lean and obese rats becomes apparent as they grow and develop obesity and the elevated POMC mRNA levels are at least partly responsible for the increased ACTH secretion in 12-week-old fatty rats.

Adrenocorticotropic Hormone↗
PubMed1992

Immunoreactive corticotropin-releasing hormone levels in the hypothalamus of female Wistar fatty rats.

We have studied immunoreactive corticotropin-releasing hormone (CRH) levels in the hypothalamus of female Wistar fatty rats, a strain with the fa gene transferred from the Zucker rat to the Wistar Kyoto rat, in an attempt to understand the role of CRH in the development of obesity. A study was conducted with 5-week- and 12-week-old female Wistar fatty rats and lean littermates. There was no significant difference in hypothalamic CRH levels between lean and obese rats at the age of 5 weeks (1887 +/- 99.6 vs. 1767 +/- 124 pg/tissue; mean +/- S.E.M.). Hypothalamic CRH immunoreactivities, however, were significantly lower in 12-week-old obese rats (2361 +/- 132 pg/tissue) than those in lean littermates (2992 +/- 118 pg/tissue; P less than 0.05). The difference of CRH contents between the lean and obese group becomes apparent as they grow up and develop obesity.

Aging↗
PubMed1992

Regulation of interleukin-1 receptors on AtT-20 mouse pituitary tumour cells.

To study the cellular mechanisms of interleukin-1 (IL-1) in the pituitary corticotroph, we studied the properties of IL-1 receptors on a mouse pituitary ACTH-producing cell line, AtT-20. Scatchard plot analysis revealed a single type of receptor with a Kd (dissociation constant) of 93 pM, and 482 binding sites/cell. [125I]IL-1 alpha binding competed with IL-1 alpha and IL-1 beta in an equimolar fashion. A 24 h pre-incubation with either CRH, epinephrine or nor-epinephrine increased the [125I]IL-1 alpha binding sites in the AtT-20 cells and conversely, a similar pre-incubation with either dexamethasone or tumour necrosis factor-alpha (TNF alpha) decreased them without affecting the affinity of the receptors in either case.

Adrenocorticotropic Hormone↗
PubMed1992

Distribution and characterization of immunoreactive corticostatin in the hypothalamic-pituitary-adrenal axis.

Using an antiserum against synthetic rabbit corticostatin-1 (CS-1), we established a specific RIA for CS-1 and examined its distribution in various tissues, including the hypothalamic-pituitary-adrenal axis. Among the tissues examined, the highest levels of CS-1-like immunoreactivity (-LI) were found in the lung and spleen. CS-1-LI was also detected at relatively high levels in the pituitary, adrenal medulla, and small intestine, while it was barely detectable in the hypothalamus. Immunocytochemical studies revealed the widespread distribution of CS-1 in these tissues. Plasma CS-1 levels averaged 7.8 ng/ml and increased to 185.4 ng/ml in the presence of infection. CS-1-LI in the adrenal gland, small intestine, and hypothalamus also increased in rabbits with active inflammation. These data suggest that CS-1 may modify the hypothalamic-pituitary-adrenal axis in an endocrine or paracrine manner in response to infection.

Animals↗
PubMed1992

Roles of interleukin-1 alpha and -1 beta in endotoxin-induced suppression of plasma gonadotropin levels in rats.

Using specific antagonists to rat interleukin (IL)-1 alpha and IL-1 beta, the roles of these IL-1s in endotoxin-induced suppression of plasma gonadotropin levels in freely-moving rats were studied. In orchiectomized rats, recombinant rat IL-1 alpha and IL-1 beta administered into the lateral ventricles almost equipotently suppressed plasma LH levels. Twenty five micrograms of bacterial endotoxin or lipopolysaccharide (LPS) administered similarly showed a comparable effect as that of 1 microgram IL-1 alpha or IL-1 beta, and completely lowered plasma LH levels by 60 min after the injection. To examine the roles of endogenous IL-1 alpha and IL-1 beta, anti-rat IL-1 alpha antiserum (anti-IL-1 alpha) and a recombinant human IL-1 receptor antagonist (IL-1ra) were used as specific blockers for IL-1 alpha and IL-1 beta, respectively. Anti-IL-1 alpha (10 microliters) or IL-1ra (10 micrograms) administered intracerebroventricularly (icv) with 25 micrograms LPS, significantly attenuated the LPS-induced effect on plasma LH levels during the first 60 min after LPS infusion, but not during the second 60 min. LPS at a dose of 5 micrograms induced smaller but still significant changes in plasma LH levels compared with 25 micrograms LPS or 1 microgram IL-1 beta. IL-1ra (10 micrograms) completely blocked LH suppression induced by 1 microgram IL-1 beta, but did not completely reverse the changes of LH induced by 5 micrograms LPS. IL-1ra injected iv also significantly attenuated the early suppressive effect of iv administered LPS, but not its late effect on plasma LH levels. However, iv administered IL-1ra had no influence on the effects of icv administered LPS. These data indicate that at least a part of plasma LH suppression caused by icv administered LPS is mediated via IL-1 alpha and IL-1 beta synthesized within the brain, while factor(s) other than IL-1 also participate in the LPS-induced change, particularly during the later period. A similar mechanism may also work peripherally in the case of iv administered LPS-induced plasma LH suppression.

Animals↗
PubMed1992

Effects of repetitive administration of recombinant human interleukin-1 beta, an analog or corticotropin-releasing hormone combined with lysine vasopressin on rats with glucocorticoid-induced secondary adrenocortical insufficiency.

We investigated effects of corticotropin-releasing hormone (CRH), lysine vasopressin and interleukin (IL)-1 beta[1-148], a less pyrogenic analog of human IL-1 beta, on the hypothalamo-pituitary-adrenal axis in a rat model of secondary adrenocortical insufficiency. After 2 weeks of corticosterone 21-sodium succinate treatment, hypothalamic CRH, anterior pituitary adrenocorticotropic hormone (ACTH) and the adrenal weight of the rats decreased significantly and their plasma ACTH showed a significantly smaller response to ether stress, as did plasma corticosterone level. A mixed solution of CRH (10 micrograms) and lysine vasopressin (2 micrograms) or recombinant human IL-1 beta[1-148] (1 micrograms), administered to these rats for 7 days, apparently accelerated the recovery of the pituitary and adrenocortical responsiveness to ether stress and significantly increased the recovery rate of anterior pituitary ACTH contents and adrenal weight. The IL-1 beta analog also increased hypothalamic CRH. These data indicated that, in a rat model with glucocorticoid-induced adrenocortical insufficiency, synthesis and release of hypothalamic CRH, pituitary ACTH and adrenal glucocorticoid were all considerably affected. CRH combined with lysine vasopressin or a less pyrogenic IL-1 beta analog, when administered to these rats, accelerated the recovery of the pituitary and the adrenocortical functions significantly, suggesting the potential clinical usefulness of these peptides.

Adrenal Insufficiency↗
PubMed1991

Effects of interleukins on plasma arginine vasopressin and oxytocin levels in conscious, freely moving rats.

To elucidate whether interleukins are involved in vasopressin or oxytocin release during cytokine-related stressful conditions, we examined the effects of human interleukin-1 beta and interleukin-6 on plasma vasopressin and oxytocin levels in rats. Interleukin-1 beta administrated intravenously stimulated both the vasopressin and oxytocin secretion in dose-dependent manners. Neither hormone release was observed following interleukin-6 administration. Pretreatment with aspirin significantly attenuated the effects of interleukin-1 beta on both the vasopressin and oxytocin levels. SC-19220, a prostaglandin E2 receptor antagonist, did not affect the interleukin-1 beta-induced increase of plasma oxytocin levels, but almost completely abolished its effect on plasma vasopressin levels. These results suggest that under certain stressful conditions which accompany the stimulation of cytokine production, interleukin-1 is involved in the increase of plasma vasopressin and oxytocin levels and, moreover, different kinds of prostaglandins are suggested to participate in these interleukin-1-induced hormone release.

Animals↗
PubMed1991

Molecular mechanisms of glucocorticoid inhibition of human proopiomelanocortin gene transcription.

The gene encoding proopiomelanocortin(POMC) offers an interesting model for negative regulation of gene transcription by glucocorticoids. A fragment of human genomic DNA containing the entire POMC gene, together with the neo marker gene, was introduced by transfection into the ACTH-producing mouse pituitary tumor cell line, AtT-20, and the mouse fibroblast L cell line. In the transformed AtT-20 cells the human POMC gene was transcribed correctly and the transcript was spliced faithfully. Furthermore, the addition of dexamethasone to the transformed AtT-20 cells resulted in a 40% reduction of the human POMC mRNA levels. Deletion analysis demonstrated that no more than 417 bp in the 5'-flanking region of the human POMC gene are required for transcriptional repression by glucocorticoid. This region was also responsible for the transcription induction of the human POMC gene by cyclic AMP (cAMP). In the transformed L cells, however, most of the transcripts of the human POMC gene were not correctly initiated. The addition of dexamethasone to the transformed L cells did not significantly affect the content of human POMC mRNA, although these cells expressed glucocorticoid receptor(GR). However, the increase of the transcripts by forskolin, a post-receptor adenylate cyclase-activating agent, was partially but significantly suppressed by dexamethasone in the transformed L cells. These results suggest that binding of GR to the negative glucocorticoid response element (nGRE) could lead to steric occlusion of positive transcription factors, such as cAMP-response element binding protein and tissue specific factors or that GR bound to nGRE could interact with DNA-bound positive factors in such a way as to prevent their transcriptional stimulatory activity.

Animals↗
PubMed1991

Prostaglandin-dependent in vitro stimulation of adrenocortical steroidogenesis by interleukins.

The effects of interleukins on adrenal steroidogenesis and their mode of action were studied using cultured rat adrenal cells. The addition of rat interleukin-1 alpha (IL-1 alpha) or rat IL-2 increased corticosterone levels in the medium in a concentration-dependent manner during 24 h of incubation. The minimum, half-maximum, and maximum effective concentrations of both rat IL-1 alpha and rat IL-2 were almost same (approximately 3, 10, and 100 U/ml, respectively). After a latent period, the effect became apparent after 12 h of incubation. Human IL-1 beta and human IL-6 also showed a stimulatory effect on corticosterone production, whereas human IL-2 was inactive in this system. To clarify the cellular mechanism of these stimulatory effects, we measured the levels of prostaglandin E2 (PGE2) and cAMP in the cells and media as well as the corticosterone levels. Corticosterone production stimulated by IL-1 alpha or IL-2 was accompanied by intracellular and extracellular cAMP and PGE2 accumulation. Although the stimulation of both cAMP and corticosterone was observed only after 12 h of incubation, PGE2 levels increased during the first 4 h of incubation. Corticosterone, cAMP, and PGE2 production stimulated by ILs was almost completely blocked by the addition of 0.1 mM aspirin, a cyclooxygenase inhibitor. Lipoxygenase inhibitors, i.e. AA-861, nordihydroguaiaretic acid, and 5,8,11,14-eicosatetrynoic acid, did not abolish corticosterone production stimulated by ILs. Submaximal doses of IL-1 alpha and IL-2 synergistically stimulated PGE2 production, but did not have even additional effects on cAMP and corticosterone levels. On the other hand, submaximal doses of ACTH, which did not significantly affect PGE2 levels, acted synergistically with IL to increase cAMP and corticosterone levels in these cells. These results indicate that 1) IL-1 alpha and IL-2 directly stimulate glucocorticoid synthesis in a dose- and time-dependent manner; 2) a half-maximum effective concentration of ACTH acts synergistically with IL in stimulating glucocorticoidogenesis; 3) the stimulatory process initially requires PGs, followed by the activation of the adenylate cyclase system; 4) although the profiles of steroidogenic action of IL-1 alpha and IL-2 are quite similar, they may exert their effects through different mechanisms in their early steps of PGE2 production; and 5) the low effective concentrations of both cytokines suggest possible physiological or pathophysiological roles of circulating cytokines in the glucocorticoidogenesis under certain conditions.

Adrenal Cortex↗
PubMed1991

Biphasic changes in hypothalamo-pituitary-adrenal function during the early recovery period after major abdominal surgery.

Regulatory mechanisms of the hypothalamo-pituitary-adrenal (H-P-A) axis during and after major abdominal surgery were studied in a group of patients who underwent upper abdominal surgery. We first examined the general profile of the changes of the H-P-A axis from the day before surgery to the seventh day after surgery. On the day of surgery, plasma levels of CRH, ACTH, and cortisol were all significantly elevated after skin incision (phase I). During the next 2 days, plasma cortisol levels remained significantly elevated, and the both plasma CRH and ACTH levels were suppressed below the control levels obtained on the day before surgery (phase II). Several additional studies, carried out to analyze the mechanism that maintains the high plasma cortisol levels, revealed the following features of the H-P-A axis during phase II. Plasma free cortisol levels in this phase were higher than those during the preoperative period. The exogenously administered hydrocortisone clearance rate in phase II did not differ from that observed on the day before surgery. Dexamethasone administration resulted in a decrease in plasma cortisol levels similar to that observed preoperatively. Conversely, the ACTH-stimulated cortisol increase was significantly greater in phase II than that observed preoperatively. These results suggest that during and after major surgical stress, the H-P-A axis undergoes a biphasic change in the pattern of the stress response and during the second phase, not the continuous hypothalamo-pituitary drive but the increased adrenal responsiveness to ACTH is responsible at least in part for maintaining the elevated plasma cortisol level.

Abdomen↗