In vitro effects of CINC/gro, a member of the interleukin-8 family, on interleukin-6 secretion by rat posterior pituitary cells

We investigated the effects of CINC/gro on IL-6 secretion by rat posterior pituitary cells. CINC/gro immunoreactivity was already detected in 1-h conditioned medium of normal posterior pituitary cells, and it increased significantly in a time-dependent manner during the first 24 h of culture. This immunoreactivity could be induced by TNF-alpha in a dose-dependent manner. On the other hand, CINC/gro stimulated IL-6 secretion by posterior pituitary monolayer cultures in a concentration dependent manner. Thus, CINC/gro significantly (P < 0.01) increased the secretion of IL-6 within 13 h of incubation, and this effect continued throughout 24 h of incubation. The stimulatory effect of 100 ng/ml CINC/gro on IL-6 secretion was completely blocked by 24-h incubation with 100 ng/ml IAP. These data demonstrate a new biological activity for CINC/gro in the posterior pituitary system.     

Unimpaired postreceptor regulation of luteinizing hormone secretion by gonadotropin-releasing hormone and estrogen in aged rat anterior pituitary cells

Delayed, attenuated, or absence of the proestrous LH surge occurs in aging rats. To assess how aging affects the positive feedback action of 17 beta-estradiol (E2) on the pituitary, we determined the responsiveness of rat pituitary cells to GnRH and the secretagogues affecting intracellular signal transduction mechanisms in the presence or absence of E2. We also correlated the LH response to pituitary LH content. Anterior pituitaries excised from ovariectomized Sprague-Dawley rats, either young (3-4 months) or old (19-20 months), were enzymatically dispersed and then pretreated with or without E2 (0.6 nM) for 48 h, followed by incubation for 3 h with or without various secretagogues. The secretagogues included GnRH (1 and 10 nM), veratridine (increases Ca2+ influx; 5 and 10 microM), and phorbol 12-myristate 13-acetate (a protein kinase-C activator; 10 and 100 nM). LH in media and cells were measured by RIA and expressed on the basis of cellular DNA. GnRH, veratridine, and phorbol 12-myristate 13-acetate at all doses stimulated (P < 0.01) LH release in cells from both young and old rats. E2 stimulated (P < 0.05 to P < 0.01) all secretagogue-induced LH release in cells from both young and old rats, but only basal LH release (P < 0.05) in cells from young rats. The magnitude of both basal and secretagogue-induced LH release in either the presence or absence of E2 was smaller (P < 0.01) in cells from old than in those from young rats. The initial cellular LH was lower (P < 0.01) in cells from old than in those from young rats. The LH-releasing ability (expressed as a percentage of total cellular LH) of cells from old rats was identical (P > 0.05) to that of cells from young rats under all conditions studied. These results suggest that the reduced magnitude of LH release by cells from old rats may be attributed to reduced cellular LH, rather than to impaired estrogen feedback or impaired signal transduction mechanisms. It remains to be determined whether LH biosynthesis per cell and/or the number of gonadotropes decrease with age.     

In vitro 2,3,7,8-tetrachlorodibenzo-p-dioxin interference with the anterior pituitary hormone adrenocorticortropin

Pharmacological effects of acute treatment with venlafaxine (VEN), a clinically active antidepressant [a noradrenaline (NA) and 5-hydroxytryptamine (5-HT) reuptake inhibitor without any affinity for neurotransmitter receptors] were studied in mice and rats. VEN inhibited the reserpine- or apomorphine-induced hypothermia and enhanced the L-5-HTP-induced head twitches in mice. It reduced the immobility time in Porsolt's test in mice and rats, but either did not change the locomotor activity (mice) or decreased it (rats). VEN reduced the locomotor hyperactivity induced by amphetamine (AMP), apomorphine (APO) and quinpirole (QUI), as well as the APO-induced stereotypy; the stereotypy induced by AMP in rats was prolonged. VEN neither changed the clonidine-induced aggressiveness in mice nor the behavioral syndrome induced by oxotremorine in rats. The obtained results indicate that VEN, given acutely, shows a pharmacological profile similar to that of tricyclic NA and 5-HT reuptake inhibitors. In contrast to the antidepressants mentioned above, VEN does not exhibit an alpha 1-adrenolytic or a cholinolytic activity (in vivo tests).     

Morphological alteration of cultured tracheobronchial epithelial cells is accompanied by the expression of chemokines, MCP-1 and CINC/gro, in rats

Research on regressive group processes such as Janis' (1982) "groupthink" phenomenon has rarely focused on work groups in authentic settings. In this study, teams from six different organisations (n = 308) were studied by using a groupthink questionnaire constructed in accordance with the symptoms of groupthink described by Janis. It was hypothesised that groupthink could be described as a bipolar construct identifying either an omnipotent or a depressive variant of a group's delusions about its own and other groups' features. The questionnaire showed reasonably good reliability as a whole and a factor analysis identified three factors in line with the proposed theoretical model in which the two different types of groupthink can be distinguished. We propose that any group might have a tendency or predisposition to react in either of the two directions during provocative circumstances. The six different organisations exhibited different types of groupthink to a varying degree. A religious sect was the one most characterised by omnipotent groupthink, while a technological company and a psychiatric team seemed to be the ones with most features of depressive groupthink.     

Campylobacter jejuni-stimulated secretion of interleukin-8 by INT407 cells

STUDY OBJECTIVES: To examine the effect of three titration schedules on the tolerability of tramadol, and to determine whether slow titration would reduce the frequency of drug discontinuation due to adverse events. DESIGN: Multicenter, outpatient, double-blind, parallel study. SETTING: Twenty-eight outpatient study centers. SUBJECTS: Four hundred sixty-five patients with chronic joint pain Interventions. Patients were randomized into one of four treatment groups for 14 days: placebo, or tramadol dosage titrated at 1, 4, or 10 days to achieve the study target dosage of 200 mg/day. They continued taking their dosage of nonsteroidal antiinflammatory drug during the study. Each group was examined to determine if slower titration resulted in a statistically significant trend toward fewer discontinuations due to nausea and/or vomiting and dizziness and/or vertigo. Discontinuation due to any adverse event was similarly analyzed. If the trend was statistically significant, pairwise comparisons were performed to determine the statistical significance among titration rates. MEASUREMENTS AND MAIN RESULTS: A statistically significant trend was seen toward fewer discontinuations as a result of nausea/vomiting, dizziness/vertigo, and any adverse event as the titration rate decreased. Patients with 10-day titration rate required the fewest discontinuations, and this rate was statistically significantly different from both the 1- and 4-day rates for discontinuations. CONCLUSION: A slower rate of initiating tramadol therapy (50-mg increments every 3 days) improved tolerability with significantly fewer discontinuations due to dizziness or vertigo.     

In vitro modulatory effects of interleukin-3 on macrophage activation induced by interleukin-2

BACKGROUND: The concomitant activation of macrophage-mediated immunosuppressive events might represent one of the most important biologic factors responsible for the decreased efficacy of cancer immunotherapies, including that of interleukin (IL)-2. In previous studies, the authors observed that the increase in the soluble IL-2 receptor (SIL-2R) and neopterin levels was related to the generation of macrophage-mediated immunosuppression and associated with a reduced clinical efficacy during IL-2 cancer immunotherapy. Because both cytokines and neurohormones may influence the macrophage system, the current study was done to evaluate the effects of IL-3 and of the pineal hormone melatonin (MLT) on monocyte response to IL-2 administration. METHODS: Peripheral blood monocytes were incubated with different concentrations of IL-2, IL-3, and MLT, either alone or in association. RESULTS: SIL-2R, neopterin, and tumor necrosis factor-alpha mean concentrations in the medium significantly increased during incubation with IL-2 at a concentration of 100 Cetus units/ml. IL-3 alone, at a dose of 10 ng/ml, also stimulated tumor necrosis factor release; no effect was found on SIL-2R and neopterin. The IL-2-induced neopterin rise was blocked by a concomitant incubation with IL-3 at a dose of 10 ng/ml. Finally, the concomitant incubation with IL-3 and MLT further inhibited neopterin release and significantly decreased IL-2-induced SIL-2R secretion. CONCLUSIONS: These results suggest that IL-3 alone or in association with MLT may modulate macrophage functions during cancer immunotherapy with IL-2 and decrease the IL-2-induced macrophage activation.     

The effects of GnRH and adrenergic agents on PRL and beta-endorphin secretion by porcine pituitary cells in vitro

The direct effects of alpha- and beta-adrenergic agents on PRL and beta-endorphin (beta-END) secretion in vitro by porcine pituitary cells have been investigated. Pituitary glands were obtained from mature gilts, which were ovariectomised (OVX) one month before slaughter. Ovariectomised gilts, assigned to four groups, were primed with: (1) vehicle (OVX); (2) and (3) oestradiol benzoate (EB; 2.5 mg/100 kg b.w.) at 30-36 h (OVX+EB I) and 60-66 h (OVX+EB II) before slaughter, respectively; and (4) progesterone (P4; 120 mg/100 kg b.w.) for 5 consecutive days before slaughter (OVX+P4). Isolated anterior pituitary cells were submitted to 3.5 h incubation in the presence of GnRH, alpha- and beta-adrenergic agonists [phenylephrine (PHEN) and isoproterenol (ISOP), respectively], or alpha- and beta-adrenergic blockers [phentolamine (PHENT) and propranolol (PROP), respectively]. The culture media were assayed for PRL (exp. I) and beta-endorphin-like immunoreactivity (beta-END-LI) (experiment II). In experiment I, GnRH did not influence PRL release by pituitary cells in all experimental groups. Some of tested doses of adrenergic agonists, PHEN and ISOP, increased PRL release from pituitary cells of OVX gilts, but not from those of OVX+EB I animals. In the OVX+EB II group, PHEN alone, but ISOP with PROP, potentiated PRL secretion by the cells. In OVX+P4 animals, PHEN alone or in combination with PHENT and also ISOP alone or with PROP enhanced PRL output from the cells. In experiment II, addition of GnRH increased beta-END-LI release from pituitary cells only in the OVX+EB II group. PHEN and PHENT potentiated beta-END-LI secretion by pituitary cells in OVX+EB II and OVX+P4 groups, while ISOP and PROP increased beta-END-LI secretion by the cells of OVX and OVX+EB II animals. In turn, in the OVX+EB I group, effect of PHENT and PROP on PRL secretion by pituitary cells was inhibitory. In conclusion, our results suggest that adrenergic agents can modulate PRL and beta-END secretion by porcine pituitary cells in a manner dependent on the hormonal status of gilts.     

Interaction of activin A and gonadal steroids on FSH secretion from primary cultured rat anterior pituitary cells

To clarify the mechanism of FSH secretion from the pituitary induced by activin A, we studied the interaction between activin A and gonadal steroids in inducing FSH release from primary cultured female rat pituitary cells in serum-free medium. The basal release of FSH was stimulated by activin A, testosterone (T) and progesterone (P), and T and P also facilitated basal FSH release stimulated by activin A. The GnRH-stimulated FSH release was facilitated by activin A, P and 17 beta-estradiol (E2), but suppressed by T. The effect of activin A on GnRH-stimulated FSH release was facilitated by P, but not affected by T or E2. These findings suggested that the interaction between activin A and T or P may be involved in the regulation of FSH secretion during the estrus cycle in rats.     

Effects of interleukins on secretion of luteinizing hormone from ovine pituitary cells

OBJECTIVE: To determine whether cytokines of homologous species might mediate the stimulatory effects of endotoxin on release of luteinizing hormone (LH) from pituitary cells. SAMPLE POPULATION: Cells from pituitary glands collected from 8- to 14-month-old wethers. PROCEDURE: Cells from the anterior pituitary gland were cultured in the presence of recombinant ovine or bovine cytokines (interleukin [IL]-1alpha, IL-1beta, and IL-2), tumor necrosis factor-alpha (TNF), and interferon-gamma (IFN-gamma). Luteinizing hormone that was released into the medium was measured. Cells were also cultured with modulators of signal transduction pathways to evaluate the second messenger system used by IL-1 alpha and IL-1beta. RESULTS: Similar to effects of endotoxin, IL-1alpha and IL-1beta stimulated release of LH. Interleukin 2, TNF, and IFN-gamma did not have a detectable effect on release of LH. Stimulation of LH release by IL-1alpha and IL-1beta required activation of voltage-dependent Ca2+ channels and appeared to involve protein kinase C. CONCLUSIONS: IL-1alpha and IL-1beta may mediate the direct stimulatory effect of endotoxin on release of LH in vitro. Interleukin 2, TNF, and IFN-gamma do not have a direct effect on release of LH; therefore, they do not mediate this effect of endotoxin. CLINICAL RELEVANCE: Stressors, including infection, are often associated with reduced fertility. Infection resulting in endotoxin release, production of interleukins, or both, can lead to direct stimulation of LH release from the pituitary gland. Inopportune release of LH via cytokines may interfere with normal pulsatile release of LH, thereby suppressing gonadal function.     

In vitro application of testosterone potentiates gonadotropin-releasing hormone-stimulated gonadotropin-II secretion from cultured goldfish pituitary cells

This report describes the methods used in conducting a long-term follow-up study and the factors associated with the successful location of subjects. In 1987-91, we selected, from among the women who were born in 1959-66 as members of the Philadelphia and Providence cohorts of the Collaborative Perinatal Project (CPP), 391 who were preterm at birth, 413 who were small-for-gestational age (SGA) and 978 who were term and appropriately grown; 1314 were from Philadelphia and 468 from Providence. Tracing was accomplished using original CPP records, telephone directories, voter registration and driver's licence records, birth certificate files and credit bureaux. A total of 61% of the women were located, 55% at Philadelphia and 77% at Providence. After adjustment, the odds ratio for ease of location, compared with women who were term and appropriately grown, was 0.85 [95% CI 0.66-1.11] for women who were preterm and 1.02 [0.78-1.34] for women who were SGA. In Philadelphia, African-American women were more likely than white women to be located, but in Providence, African-American women were less likely than white women to be located. Women whose own mothers were older at the time of their birth were more likely to be located, as were those who had more siblings followed in the CPP. Compared with women who did not complete their original CPP examinations at ages 4 and 7 years, those whose original CPP follow-up was more complete were more likely to be located. These findings demonstrate that long-term follow up in a US urban setting can be accomplished, and that successful location was not associated with birth status.     

Orexins, a novel family of hypothalamic neuropeptides, modulate pituitary luteinizing hormone secretion in an ovarian steroid-dependent manner

Recent findings have focused attention on the role of apoptosis in neurodegenerative diseases, however, the apoptotic process in child-onset brain disorders has been little investigated. Xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are hereditary disorders characterized by impaired DNA repair and neurodegeneration. We investigated apoptotic cell death in the cerebellum of five cases of XP group A (XPA), four cases of CS, and twelve controls, using TdT-mediated DIG-dUTP nick-end labeling (TUNEL) and immunohistochemical staining for bcl-2, bcl-x, p53, bax, BDNF and Trk B. The TUNEL-positive cells were found in the granule cells of the cerebellar cortex of two patients with XPA and two patients with CS, whereas such cells were not detected in the cerebellar cortex in controls. Upregulation of bcl-2 or BDNF was not observed, and bcl-x expression was not altered. Some patients showed nuclear expression of p53 in the granule cells and/or molecular layer, bax-positive glial cells in the cerebellar white matter, and a few Trk B-positive cells in the granular layer. These findings suggest that apoptotic cell death can be involved in the cerebellar degeneration in patients with hereditary defects in DNA repair mechanisms.     

Yersinia enterocolitica-induced interleukin-8 secretion by human intestinal epithelial cells depends on cell differentiation

In response to bacterial entry epithelial cells up-regulate expression and secretion of various proinflammatory cytokines, including interleukin-8 (IL-8). We studied Yersinia enterocolitica O:8-induced IL-8 secretion by intestinal epithelial cells as a function of cell differentiation. For this purpose, human T84 intestinal epithelial cells were grown on permeable supports, which led to the formation of tight monolayers of polarized intestinal epithelial cells. To analyze IL-8 secretion as a function of cell differentiation, T84 monolayers were infected from the apical or basolateral side at different stages of differentiation. Both virulent (plasmid-carrying) and nonvirulent (plasmid-cured) Y. enterocolitica strains invaded nondifferentiated T84 cells from the apical side. Yersinia invasion into T84 cells was followed by secretion of IL-8. After polarized differentiation of T84 cells Y. enterocolitica was no longer able to invade from the apical side or to induce IL-8 secretion by T84 cells. However, Y. enterocolitica invaded and induced IL-8 secretion by polarized T84 cells after infection from the basolateral side. Basolateral invasion required the presence of the Yersinia invasion locus, inv, suggesting beta1 integrin-mediated cell invasion. After basolateral infection, Yersinia-induced IL-8 secretion was not strictly dependent on cell invasion. Thus, although the plasmid-carrying Y. enterocolitica strain did not significantly invade T84 cells, it induced significant IL-8 secretion. Taken together, these data show that Yersinia-triggered IL-8 secretion by intestinal epithelial cells depends on cell differentiation and might be induced by invasion as well as by basolateral adhesion, suggesting that invasion is not essential for triggering IL-8 production. Whether IL-8 secretion is involved in the pathogenesis of Yersinia-induced abscess formation in Peyer's patch tissue remains to be shown.     

Dose-dependent effects of 17-beta-estradiol on pituitary thyrotropin content and secretion in vitro

We studied the basal and thyrotropin-releasing hormone (TRH) (50 nM) induced thyrotropin (TSH) release in isolated hemipituitaries of ovariectomized rats treated with near-physiological or high doses of 17-beta-estradiol benzoate (EB; sc, daily for 10 days) or with vehicle (untreated control rats, OVX). One group was sham-operated (normal control). The anterior pituitary glands were incubated in Krebs-Ringer bicarbonate medium, pH 7.4, at 37 degrees C in an atmosphere of 95% O2/5% CO2. Medium and pituitary TSH was measured by specific RIA (NIDDK-RP-3). Ovariectomy induced a decrease (P < 0.05) in basal TSH release (normal control = 44.1 +/- 7.2; OVX = 14.7 +/- 3.0 ng/ml) and tended to reduce TRH-stimulated TSH release (normal control = 33.0 +/- 8.1; OVX = 16.6 +/- 2.4 ng/ml). The lowest dose of EB (0.7 microgram/100 g body weight) did not reverse this alteration, but markedly increased the pituitary TSH content (0.6 +/- 0.06 microgram/hemipituitary; P < 0.05) above that of OVX (0.4 +/- 0.03 microgram/hemipituitary) and normal rats (0.46 +/- 0.03 microgram/hemipituitary). The intermediate EB dose (1.4 micrograms/100 g body weight) induced a nonsignificant tendency to a higher TSH response to TRH compared to OVX and a lower response compared to normal rats. Conversely, in the rats treated with the highest dose (14 micrograms/100 g body weight), serum 17-beta-estradiol was 17 times higher than normal, and the basal and TRH-stimulated TSH release, as well as the pituitary TSH content, was significantly (P < 0.05) reduced compared to normal rats and tended to be even lower than the values observed for the vehicle-treated OVX group, suggesting an inhibitory effect of hyperestrogenism. In conclusion, while reinforcing the concept of a positive physiological regulatory role of estradiol on the TSH response to TRH and on the pituitary stores of the hormone, the present results suggest an inhibitory effect of high levels of estrogen on these responses.     

Effect of pituitary adenyl cyclase activating polypeptide on the cells of anterior pituitary cells

Pituitary adenylate cyclase activating polypeptide was first isolated from sheep hypothalamus by its potent activity in stimulating cyclic adenosine monophosphate production in anterior pituitary cells. The present review deals with the actions of this polypeptide on anterior pituitary cell types and with the putative role of the polypeptide as a hypophysiotropic factor regulating anterior pituitary cell activity. The evidence to date is strongly suggestive that pituitary adenylate cyclase activating polypeptide may act not as a "classic" hypophysiotropic factor stimulating or modifying anterior pituitary hormone release in vivo, since it does not appear in vitro to be a particularly potent stimulator of hormone release. The polypeptide rather may modulate the responses to factors such as gonadotrop hormone releasing hormone or have more general actions by regulating hormone synthesis or cell differentiation. Pituitary adenylate cyclase activating polypeptide also has indirect actions on anterior pituitary cell activity by stimulating the release of the paracrine factor interleukin-6. Its receptors appear to be present on most of the anterior pituitary cell types and unlike many other hypophysiotropic factors, pituitary adenylate cyclase activating polypeptide interacts with most, if not all, of the anterior pituitary cell types. Its exact effects and mechanisms of action in the anterior pituitary gland are still poorly understood.     

Stimulation by urocortin of growth hormone (GH) secretion in GH-producing human pituitary adenoma cells

Urocortin (Ucn) possesses high homology with CRH and is considered to be a ligand to type-2 CRH receptor. We investigated the effect of Ucn on hormone release from cultured GH-producing human pituitary adenoma cells in vitro. GH-producing human pituitary adenoma cells were superfused on a Sephadex G-25 column. Both Ucn (10 nM) and CRH (10 nM) elicited an increase in GH release from the pituitary adenoma cells in one patient with acromegaly. In contrast, GH release from the pituitary adenoma cells was stimulated by Ucn but not by CRH in the other patient with acromegaly. These preliminary findings suggest that type-2 CRH receptors are expressed in some population of GH-producing human pituitary adenoma cells and that Ucn might be involved in GH secretion from tumorous tissues in patients with acromegaly.     

Somatostatin plays a dual, stimulatory/inhibitory role in the control of growth hormone secretion by two somatotrope subpopulations from porcine pituitary

Previous results from our laboratory demonstrated the existence of two subpopulations of porcine somatotropes of low- (LD) and high density (HD) that exhibit differences in ultrastructure and respond in an opposite manner to somatostatin (SRIF) in vitro. In LD cells, SRIF did not affect basal growth hormone (GH) release but partially blocked the stimulatory effect induced by GH-releasing factor (GRF). Conversely, SRIF paradoxically stimulated the secretory activity of HD somatotropes. Here, we have analysed in detail the basic parameters that characterize this differential response. To this end, the time- and dose-dependent effects of SRIF-14 were evaluated on separate monolayer cultures of both subpopulations. Likewise, the direct effect of the peptide on individual somatotropes from each subset was assessed by cell immunoblot assay. Finally, we compared the effects of SRIF-14 and SRIF-28 on cultures of LD and HD cells. SRIF-14 (10(-7) M) induced a rapid (30 min) and sustained (4 h) 2-fold increase in GH release from HD cells, whereas it did not affect GH secretion from LD somatotropes. Surprisingly, a low dose of SRIF (10(-15) M) stimulated GH release from both LD (154.1 +/- 8.2% of basal, P < 0.05) and HD (337.2 +/- 55.5% of basal, P < 0.05) subpopulations, even more effectively than higher doses of the peptide. Results from cell blotting showed that SRIF stimulatory effects were exerted directly upon individual somatotropes. Finally, SRIF-28 elicited similar responses to those observed for SRIF-14 in both somatotrope subpopulations, yet 10(-15) M SRIF-28 was less potent than the same dose of SRIF-14 in stimulating GH release from HD cells. Our present findings demonstrate that SRIF can function as a true GH-releasing factor in cultures of porcine pituitary cells by acting specifically and directly upon somatotropes. Furthermore, together with previous observations, these results strongly suggest that SRIF is not merely an inhibitor of GH release in pigs, but might play a dual modulatory role. Heterogeneity of the somatotrope population contributes greatly to this divergent effect of SRIF.     

In vitro production of interleukin-1, interleukin-6 and tumor necrosis factor-alpha by different blood cells in patients on intermittent peritoneal dialysis

Stevens-Johnson syndrome (SJS) is an uncommon eruptive disorder of the skin and mucous membranes with systemic manifestation. It is extremely unusual for patients with a past history of SJS to present with indications for surgery necessitating thoracotomy. We describe herein the perioperative management of a patient with SJS who underwent surgery for a spontaneous pneumothorax.