PGE2 and PGF2 alpha content in bronchoalveolar lavage fluid obtained from patients with eosinophilic pneumonia

Cell differential, prostaglandins (PGs) E2 and F2 alpha in the bronchoalveolar lavage fluid (BALF) in two patients with eosinophilic pneumonia were measured at different times in the course of the disease. Results showed markedly increased numbers of eosinophils and increased content of prostaglandin (PG) E2 in BALF obtained from the patients with eosinophilic pneumonia compared to that of normal volunteers. Interestingly, the increased content of PGE2 in BALF obtained from the patients reverted to normal range with corticosteroid treatment. This change in PGE2 content in BALF was accompanied by normalization of number and percentage of eosinophils in BALF. These findings indicated that PGE2 level in lower respiratory tract of patients with eosinophilic pneumonia may be related to an increased number of eosinophils.     

Prostaglandins and renin release: the effect of PGI2, PGE2, and 13,14-dihydro PGE2 on the baroreceptor mechanism of renin release in the dog.

We compared the ability of the vasodilator prostaglandins PGI2, PGE2, and 13,14-dihydro PGE2 to release renin when infused into the denervated, nonfiltering canine kidney in vivo. Papaverine was used as a nonprostaglandin vasodilator. All the prostaglandins tested were capable of stimulating renin secretion, with the scale of potency being 13,14-dihydro PGE2 greater than PGI2 greater than PGE2; papaverine had no effect on renin secretion. These results indicate that both PGE2 and PGI2 can stimulate renin secretion but that vasodilation per se is not a stimulus. 13,14-Dihydro PGE2 was included because it is a poorer substrate than PGE2, both for transport into cells and catabolism to inactive products, but has comparable potency to PGE2 when tested in systems with limited ability to catabolize PGE2. The fact that 13,14-dihydro PGE2 was the most potent prostaglandin tested suggests that the effects of PGE2 in our system are reduced by the kidneys' recognized ability to extract and catabolize PGE2. Since PGI2 is less avidly metabolized than PGE2 by the kidney, the differences in observed potency between PGE2 and PGI2 could be largely the result of differences in renal catabolism of the two prostaglandins rather than differences in intrinsic potency. Therefore, both PGE2 and PGI2 are candidates for the endogenous prostaglandin responsible for stimulating renin secretion.     

Antagonism by PGF2alpha of the vasodilation induced by PGE1, PGE2 and PGA1 in the canine uterus.

Prostaglandins appear to play an important role in a number of reproductive processes. The present study was designed to determine if the vasodilator action of prostaglandins of the A and E series on uterine vascular smooth muscle was mediated via a receptor and if PGF2alpha could compete for this same receptor. The data demonstrate that PGF2alpha, which by itself has no uterine vascular effect, can produce a parallel shift in the dose-response curves for certain vasodilator prostaglandins. This action, which suggests competitive antagonism, may well play a role in regulating blood flow in the nonpregnant uterus.     

Glucocorticoids and thyroid hormones stimulate biochemical and morphological differentiation of human fetal lung in organ culture

We characterized the stimulatory effects of both glucocorticoids and thyroid hormones on the surfactant system in human fetal lung. Synthesis of phosphatidylcholine (PC) and morphology were examined in explant cultures (15-24 weeks gestation) maintained 1-7 days in serum-free Waymouth's medium in a 95%-air-5% CO2 atmosphere. Control explants (no hormones) had the same rate of choline incorporation into PC between 1 and 7 days, but a significant increase in tissue PC content [82 +/- 21%, (+/- SEM), day 6 vs. 1], consistent with slow turnover of PC. [3H]Choline incorporation was stimulated 36%, 137%, and 192% by T3 (2 nM), dexamethasone (Dex; 10 nM), and T3 plus Dex, respectively, after 6 days of exposure (optimal response) compared to 19%, 38%, and 84% after 2 days of exposure. Thus, a supra-additive response occurred in the presence of both hormones and was greater at a shorter exposure time. Dex increased the percent saturation of newly synthesized PC (28.9 +/- 0.9% vs. 17.8 +/- 0.8% for control), but T3 did not, whereas both hormones increased tissue PC content (74.4 +/- 7.3% and 18.7 +/- 7.8% increase vs. control, respectively). Pulse-chase experiments with [3H]choline suggest that remodeling of unsaturated PC to saturated PC occurred during culture and was stimulated by Dex. Incorporation of [3H]acetate and [3H]glycerol into PC was stimulated by Dex (830% and 77%, respectively), but not by T3; the distribution of incorporated radioactivity among phospholipids was changed by Dex (increased counts per min into PC and phosphatidylglycerol with acetate and glycerol, respectively), but not by T3. Half-maximal stimulation of choline incorporation occurred at concentrations of Dex (2.1 nM) and T3 (0.03 nM) that are similar to the Kd values for receptor binding (5 and 0.05 nM, respectively). The relative potencies of thyroid hormones were T3 greater than T4 greater than rT3, and for corticosteroids, Dex much greater than corticosterone greater than 11-dehydrocorticosterone = cortisol greater than cortisone. Stimulation by either T3 or cortisol was reversed within 24-48 h of hormone removal. Initial treatment of explants with Dex enhanced the subsequent response to T3, but not vice versa. Culture for 4-5 days in the absence of hormones produced some morphological maturation of the epithelial cells, whereas treatment with T3 plus Dex markedly increased the number and size of lamellar bodies in epithelial cells, caused extensive proliferation of apical microvilli, and reduced glycogen deposits. Our findings are consistent with receptor-mediated stimulation of surfactant synthesis in human lung by both glucocorticoids and thyroid hormones.(ABSTRACT TRUNCATED AT 400 WORDS)     

Insulin secretion by fetal human pancreas in organ culture

Summary Whole fetal human pancreases of 12–22 weeks gestation, showed histological growth and differentiation in vitro over 3 weeks. At glucose concentrations of 1–4 g/l, there was no difference in insulin secretion into culture medium over 1 h. There was no stimulation of insulin release by D-glyceraldehyde, thus defective glucose-stimulated insulin release was probably not due to impairment of an early step in glycolysis. In the presence of 0.5 mmol/l dibutyryl cyclic AMP, insulin secretion was enhanced (0.188±0.030 versus 0.100±0.012 mU·mg tissue^-1·h^-1, p<0.001) independently of glucose concentrations. It thus appears that impairment of glucose-stimulated insulin release was unlikely to be due to insufficient intracellular cyclic AMP. Insulin release increased in response to tolbutamide and theophylline. Insulin secretion was stimulated in the presence of a fivefold increase in amino acid concentration (0.118±0.018 versus 0.031±0.008 mU·mg tissue ^-1·h^-1, p<0.001). There was a fourfold increase in basal insulin secretion from islets previously grown in high concentration of amino acids compared with standard culture medium, (0.284±0.052 versus 0.067±0.011 mU·mg tissue^-1·h^-1, p<0.001), emphasizing the important role of amino acids as substrates for B cell metabolism and development.     

Cytosolic free calcium increased by prostaglandin F2 alpha (PGF2 alpha), gonadotropin-releasing hormone, and angiotensin II in rat granulosa cells and PGF2 alpha in human granulosa cells.

Cytosolic [Ca2+]i was measured using a microspectrofluorimetric technique. Prostaglandin F2 alpha (PGF2 alpha, 10(-6) M) transiently increased the concentration of free cytosolic Ca2+ ([Ca2+]i) in individual rat and human granulosa cells. In a study examining a total of 170 individual rat and human granulosa cells, approximately 100% of rat granulosa cells and 80% of human granulosa cells tested responded to PGF2 alpha (10(-6) M). In a dose-response trial, the magnitude of the [Ca2+]i response did not vary, although a decreasing number of cells responded to decreasing PGF2 alpha concentrations (10(-5) to 10(-9) M). PGE2 (10(-4) to 10(-6) M) did not affect [Ca2+]i in rat or human granulosa cells. GnRH (10(-6) M) increased [Ca2+]i in rat but not human granulosa cells. Over 90% of rat granulosa cells tested responded. Angiotensin II (ANG II, 10(-5) M) increased [Ca2+]i in approximately 25% of rat, but not human granulosa cells. Individual rat granulosa cells which responded to GnRH responded to PGF2 alpha and vice versa. Individual rat granulosa cells which responded to ANG II responded to PGF2 alpha and GnRH. Conversely, less than 30% of individual rat granulosa cells which responded to PGF2 alpha and GnRH responded to ANG II. Desensitization (pretreatment) of rat granulosa cells by continuous hormone perifusion suggested that effects of PGF2 alpha, GnRH, and ANG II on [Ca2+]i were receptor specific. However, the effects of combined hormone treatments on [Ca2+]i were not additive. The transient increase in [Ca2+]i in response to PGF2 alpha or GnRH, alone, may be maximal. Results of this study suggested that effects of PGF2 alpha, GnRH, and ANG II receptor-ligand interactions may be at least partially mediated by transient increases in [Ca2+]i in rat granulosa cells. Similarly, effects of PGF2 alpha, but not GnRH or ANG II, receptor-ligand interactions may be mediated by transient increases in [Ca2+]i in human granulosa cells.     

Endothelins enhance prostaglandin (PGE(2) and PGF(2alpha)) biosynthesis and release by human luteal cells: evidence of a new paracrine/autocrine regulation of luteal function

We have previously shown that endothelin-1 (ET-1) is normally found in human luteal cells, where it is able to significantly inhibit both basal and hCG-induced progesterone production. To further expand our comprehension of the possible roles of endothelins (ETs) in luteal physiology, in this study we used primary cultures of luteal cells exposed to graded doses of ET-1 and ET-3; PGF(2alpha) and PGE(2) were assayed in the culture medium to investigate whether ETs also influence cyclooxygenase activity in these cells. We found that both ETs are able to significantly stimulate PGF(2alpha) and PGE(2) release in a dose- and time-dependent manner. ET-1 was always more effective than ET-3. Experiments with two endothelin receptor antagonists (the BQ485 and BQ788 compounds, which block the ET-A and ET-B receptors, respectively) showed that the two endothelins induce PG production through different receptors and signaling pathways. In conclusion, here we demonstrate the ability of ETs to influence PG synthesis and release from human luteal cells. As PGs are deeply involved in corpus luteum activity, and ETs were also able to influence progesterone production, the present new data suggest an interesting interplay among progesterone, PGs, and ETs in the control of corpus luteum physiology.     

beta-Adrenergic induction of tyrosine aminotransferase organ culture of fetal rat and fetal human liver

Isoproterenol, phenylephrine, and salbutamol (all 100 microM) induced the activity of tyrosine aminotransferase (TAT; EC 2.6.1.5) by 109%, 72%, and 141%, respectively, in organ culture of fetal human liver. Propranolol (100 microM) inhibited the effects of isoproterenol and phenylephrine. In organ culture of fetal rat liver, the induction of TAT activity by phenylephrine (100 microM) was not significantly affected by phentolamine (100 microM), whereas it was abolished by a combination of phentolamine and propranolol (both 100 microM). Isoproterenol and salbutamol caused significant increases in TAT activity, which were not affected by 100 microM atenolol but were completely inhibited by propranolol (100 microM). The results show that the fetal human liver has developed responsiveness to adrenergic stimuli at the 12th week of gestation. The adrenergic induction of TAT in fetal human liver is mediated solely by beta-adrenergic mechanisms. In the fetal rat liver, the adrenergic induction of TAT is mediated by beta 2-adrenergic receptors.     

A possible involvement of prostaglandin F2 alpha (PGF2 alpha) in Rana esculenta ovulation: effects of mammalian gonadotropin-releasing hormone on in vitro PGF2 alpha and 17 beta-estradiol production from ovary and oviduct.

The present work studied the PGF2 alpha and 17 beta-estradiol plasma levels during ovulation, and the in vitro effects of mammalian gonadotropin-releasing hormone (mGnRH) on ovarian and oviductal production of prostaglandin F2 alpha (PGF2 alpha) and 17 beta-estradiol during four different stages of the annual sexual cycle in water frog, Rana esculenta. Plasma levels of PGF2 alpha increased in ovulating frogs, with respect to preovulatory and postovulatory levels, while estradiol did not change. In addition, mGnRH increased PGF2 alpha and 17 beta-estradiol in the incubation media of ovaries taken during the recovery stage. Moreover, mGnRH increased PGF2 alpha in incubation media of oviducts collected during the reproductive stage. These findings suggest that PGF2 alpha could be involved in the control of egg deposition in the female R.     

Effect of azodisal sodium and sulphasalazine on ileostomy output of fluid and PGE2 and PGF2 alpha in subjects with a permanent ileostomy.

Azodisal sodium is a highly effective means of oral delivery of 5-amino-salicylic acid to the colonic mucosa. Administration of this drug to patients intolerant of sulphasalazine, however, occasionally results in liquid stools. In preliminary experiments, which comprised 10 healthy volunteers treated with colectomy for ulcerative colitis, ileostomy fluid output increased (p less than 0.001) during oral intake of azodisal sodium (1 g/day). In a double blind, placebo controlled crossover study, comprising eight similar volunteers, ileostomy fluid output increased (p less than 0.05) in a dose related manner during intake of azodisal sodium (1 g/day vs 2 g/day) compared with placebo or sulphasalazine (2 g/day). Concentrations of prostaglandin (PG)F2 alpha in free ileal water determined by equilibrium in vivo dialysis of ileostomy contents decreased (p less than 0.05) during intake of azodisal sodium (2 g/day), whereas concentrations of PGE2 and the output of PGE2, PGF2 alpha, and 'PGE2 + PGF2 alpha' remained unchanged. Thus increased formation of PGs is apparently not the cause of increased ileostomy fluid output associated with azodisalicylate intake.     

Pathogenesis of respiratory syncytial virus infection in ferret and fetal human tracheas in organ culture.

The pathogenesis of human respiratory syncytial virus infection was studied in ferret and fetal human tracheas in organ culture. Although the patterns of virus growth were similar in these species, the sites and morphologic consequences of virus replication differed markedly. In human trachea, synthesis of respiratory syncytial virus occurred in a population of ciliated epithelial cells, whereas other cells in the epithelial layer were spared. Virus replication was associated with cell injury characterized by ballooning degeneration and syncytium formation. In ferret trachea, virus growth occurred in fibroblasts of the lamina propria and serosa. Ciliated epithelial cells did not contain viral antigen and remained histologically normal. These observations are relevant to understanding the pathogenesis of human disease and the evaluation of animal models of respiratory syncytial virus bronchiolitis.     

Skeletal muscle PGF(2)(alpha) and PGE(2) in response to eccentric resistance exercise: influence of ibuprofen acetaminophen

PGs have been shown to modulate skeletal muscle protein metabolism as well as inflammation and pain. In nonskeletal muscle tissues, the over the counter analgesic drugs ibuprofen and acetaminophen function through suppression of PG synthesis. We previously reported that ibuprofen and acetaminophen inhibit the normal increase in skeletal muscle protein synthesis after high intensity eccentric resistance exercise. The current study examined skeletal muscle PG levels in the same subjects to further investigate the mechanisms of action of these drugs in exercised skeletal muscle. Twenty-four males (25 +/- 3 yr) were assigned to 3 groups that received the maximal over the counter dose of ibuprofen (1200 mg/d), acetaminophen (4000 mg/d), or a placebo after 10-14 sets of 10 eccentric repetitions at 120% of concentric 1 repetition maximum using the knee extensors. Preexercise and 24 h postexercise biopsies of the vastus lateralis revealed that the exercise-induced change in PGF(2alpha) in the placebo group (77%) was significantly different (P < 0.05) from those in the ibuprofen (-1%) and acetaminophen (-14%) groups. However, the exercise-induced change in PGE(2) in the placebo group (64%) was only significantly different (P < 0.05) from that in the acetaminophen group (-16%). The exercise-induced changes in PGF(2alpha) and PGE(2) were not different between the ibuprofen and acetaminophen groups. These results suggest that ibuprofen and acetaminophen have a comparable effect on suppressing the normal increase in PGF(2alpha) in human skeletal muscle after eccentric resistance exercise, which may profoundly influence the anabolic response of muscle to this form of exercise.     

The presence and release of alpha 2-antiplasmin from human platelets

An antigen immunochemically indistinguishable from plasma alpha 2- antiplasmin, the primary plasmin inhibitor, was detected in human platelets. By radioimmunoassay, 33-114 ng alpha 2-antiplasmin antigen was quantitated in the detergent-soluble extract of 10(9) washed human platelets from 10 normal donors with a mean level of 62 +/- 24 ng/10(9) platelets. Plasma alpha 2-antiplasmin, either in the platelet suspending medium or on the surface of the platelets, could account for less than 8% of the antigen present in the platelet extracts. When stimulated with thrombin, the platelets released alpha 2-antiplasmin antigen without cell lysis, and greater than 85% of the alpha 2- antiplasmin antigen was released at a high thrombin dose. At a lower dose of thrombin, alpha 2-antiplasmin and platelet factor 4 were partially released without concomitant secretion of serotonin. No alpha 2-antiplasmin antigen was detected in extracts or red blood cells, polymorphonuclear leukocytes, and adherent and nonadherent mononuclear cells. Thus, the platelet is the only peripheral blood cell containing significant amounts of alpha 2-antiplasmin.     

Defective arachidonate release and PGE2 production in Gi alpha2-deficient intestinal and colonic subepithelial myofibroblasts

BACKGROUND: Mice lacking the pertussis toxin-sensitive G-protein subunit Gi alpha2 spontaneously develop colitis and colon cancer. In the gut, arachidonate-derived prostaglandin E2 (PGE2) modulates intestinal immune responses and epithelial restitution and is derived largely from subepithelial myofibroblasts. METHODS: We tested whether known decreases in arachidonate release in cells lacking Gi alpha2 would result in decreased PGE2 production and tissue PGE2 levels. PGE2 levels were significantly decreased in the colon of Gi alpha2-/- mice. RESULTS: Gi alpha2-/- myofibroblasts from the small intestine and colon both released asymptotically equal to 50% less arachidonate and 3- to 7-fold less PGE2 and 6-keto PGF1alpha in response to adenosine triphosphate, thrombin, tumor necrosis factor-alpha, or lipopolysaccharide, in a partially cyclooxygenase (COX)-2-dependent manner. Decreased arachidonate release did not appear to be caused by a defect in cPLA2 translocation in the absence of Gi alpha2. Basal myofibroblast COX-1 and COX-2 expression was downregulated in Gi alpha2-/- cells. No differences in proliferation rates were found between serum-starved or serum-activated wild-type (WT) and Gi alpha2-/- myofibroblasts. Finally, treatment of Gi alpha2-/- mice with the EP4-specific PGE2 receptor agonist ONO-AE1-329 significantly decreased the severity of established colitis. CONCLUSIONS: These findings confirm a requirement for Gi alpha2 in intestinal and colonic myofibroblast-derived prostanoid production and confirm the importance of mucosal PGE2 in the suppression of colitis.     

Angiotensin stimulation of vasopressin release from the rat hypothalamo-neurohypophyseal system in organ culture.

Angiotensin II (AII) stimulated vasopressin (VP) release from the rat hypothalamo-neurohypophyseal system (HNS) in organ culture in a concentration-dependent manner. Exposure to AII at 10(-8) M for 1 hr yielded a 1.8-fold increase in VP release over control release (P less than 0.01), while a 1-h exposure to 10(-5) M AII resulted in a 4-fold increment over control VP release by HNS explants maintained in organ culture for 3 days (P less than 0.01). Saralasin, an AII antagonist, blocked AII stimulation of VP release without significantly altering basal VP release by the HNS explants. Saralasin did not interfere with stimulation of VP release by acetylcholine or nicotine. Tetrodotoxin (10(-7) g/ml) also blocked AII stimulation of VP release. These findings suggest that action potentials are generated in response to AII stimulation of specific receptors in the HNS and are requisite for VP release in response to this stimulus.