Prostaglandin transporter (OATP2A1/SLCO2A1) contributes to local disposition of eicosapentaenoic acid-derived PGE3.

Eicosapentaenoic acid (EPA)-derived prostaglandin E3 (PGE3) possesses an anti-inflammatory effect; however, information for transporters that regulate its peri-cellular concentration is limited. The present study, therefore, aimed to clarify transporters involved in local disposition of PGE3. PGE3 uptake was assessed in HEK293 cells transfected with OATP2A1/SLCO2A1, OATP1B1/SLCO1B1, OATP2B1/SLCO2B1, OAT1/SLC22A6, OCT1/SLC22A1 or OCT2/SLC22A2 genes, compared with HEK293 cells transfected with plasmid vector alone (Mock). PGE3 uptake by OATP2A1-expressing HEK293 cells (HEK/2A1) was the highest and followed by HEK/1B1, while no significantly higher uptake of PGE3 than Mock cells was detected by other transporters. Saturation kinetics in PGE3 uptake by HEK/2A1 estimated the Km as 7.202 ± 0.595 µM, which was 22 times higher than that of PGE2 (Km=0.331 ± 0.131 µM). Furthermore, tissue disposition of PGE3 was examined in wild-type (WT) and Slco2a1-deficient (Slco2a1(-/-)) mice after oral administration of EPA ethyl ester (EPA-E) when they underwent intraperitoneal injection of endotoxin (e.g., lipopolysaccharide). PGE3 concentration was significantly higher in the lung, and tended to increase in the colon, stomach, and kidney of Slco2a1(-/-), compared to WT mice. Ratio of PGE2 metabolite 15-keto PGE2 over PGE2 concentration was significantly lower in the lung and colon of Slco2a1(-/-) than that of WT mice, suggesting that PGE3 metabolism is downregulated in Slco2a1(-/-) mice. In conclusion, PGE3 was found to be a substrate of OATP2A1, and local disposition of PGE3 could be regulated by OATP2A1 at least in the lung.

Vitreous nonsteroidal antiinflammatory drug concentrations and prostaglandin E2 levels in vitrectomy patients treated with ketorolac 0.4%, bromfenac 0.09%, and nepafenac 0.1%.

PURPOSE: To assess vitreous concentrations of nonsteroidal antiinflammatory drugs (NSAIDs) and prostaglandin E(2) in patients treated with NSAIDs before vitrectomy. METHODS: This was an investigator-masked, randomized, multicenter study. Patients received ketorolac 0.4% 4 times a day, bromfenac 0.09% 2 times a day, nepafenac 0.1% 3 times a day, or no NSAID for 3 days before surgery. Nonsteroidal antiinflammatory drugs and prostaglandin E(2) levels were determined in vitreous samples collected at the beginning of surgery. RESULTS: Thirty-one patients were included in the analyses. The mean (SD) vitreous concentrations were as follows: ketorolac 2.8 (3.2) ng/mL, bromfenac 0.96 (0.31) ng/mL, nepafenac 1.1 (0.6) ng/mL, and amfenac 2.0 (0.8) ng/mL aligned with the initial concentrations of the topical NSAIDs. Mean (SD) vitreous prostaglandin E(2) levels of the control patients and those treated with ketorolac 0.4%, bromfenac 0.09%, or nepafenac 0.1% were 270.6 (91.7) pg/mL, 189.6 (50.2) pg/mL, 247.2 (38.3) pg/mL, and 267.7 (99.7) pg/mL, respectively. Patients treated with ketorolac 0.4% had significantly lower prostaglandin E(2) levels than those treated with no NSAID (P = 0.047) or nepafenac 0.1% (P = 0.028). CONCLUSION: All three NSAIDs penetrated into the vitreous cavity. Topical therapy with ketorolac may lower preoperative vitreous prostaglandin E(2) levels, which may have a clinical impact on the management of prostaglandin-mediated diseases, including cystoid macular edema.

Long-term NSAID treatment directly decreases COX-2 and mPGES-1 production in the articular cartilage of patients with osteoarthritis.

OBJECTIVE: To simultaneously study the effect of a selective cyclooxygenase-2 (COX-2) inhibitor and that of a classic non-steroidal anti-inflammatory drug (NSAID) on the expression of pro-inflammatory genes in the cartilage of patients with severe knee osteoarthritis (OA) and in cultured human OA chondrocytes. METHODS: A 3-month clinical trial was carried out on 30 patients with severe knee OA scheduled for knee replacement surgery. Patients were randomized into two groups: patients treated with celecoxib (CBX) and patients treated with aceclofenac (ACF). OA patients who did not want to be treated served as the control group. After surgery, cartilage was processed for molecular biology studies. We also employed cultured chondrocytes from different OA patients to examine NSAID effects on pro-inflammatory gene expression in cells stimulated with interleukin (IL)-1beta. RESULTS: Both CBX and ACF inhibited COX-2, microsomal prostaglandin E synthase-1 (mPGES-1) and inducible nitric oxide synthase (iNOS) synthesis in the articular cartilage of OA patients. In cultured chondrocytes, both NSAID decreased COX-2 and mPGES-1 synthesis and prostaglandin E2 (PGE2) release induced by IL-1beta, while no effect was observed on nitric oxide or iNOS synthesis. In OA patients, only CBX decreased tumor necrosis factor alpha and IL-1beta expression in the cartilage, while both NSAID diminished IL-1beta induced cytokine synthesis in cultured OA chondrocytes. CONCLUSIONS: Both NSAID diminished PGE2 release and induced a decrease in COX-2 and mPGES-1 synthesis in the cartilage from OA patients and in OA chondrocytes. These data suggest that prolonged therapy with PGE2 blocking agents decreases PGE2 production not only by direct inhibition of COX-2 activity, but also by down-regulating COX-2 and mPGES-1 synthesis in the cartilage. However, CBX and ACF seem to have a different anti-inflammatory profile in controlling pro-inflammatory gene expression in the cartilage.

Segmental heterogeneity of electrogenic secretions in human ascending colon and rectum.

AIMS: We have attempted to ascertain putative segmental differences in the secretory responses of the human ascending colon and rectum. METHODS: From the mucosal biopsy samples of two segments, the short-circuit current (I(sc)) and tissue resistance (R(te)) were compared under control conditions, as well as after the induction of secretion, using a modified Ussing chamber. We also performed semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to detect and quantify transport proteins. RESULTS: The spontaneous I(sc) in the ascending colon was found to be greater than that in the rectum (P<0.01), whereas isobutylmethylxanthine/forskolin and carbachol (CCh) induced a greater rise in I(sc) in the rectum than in the ascending colon (P<0.05). When coupled with indomethacin pretreatment, the increase in Delta I(sc) after the addition of CCh and forskolin was significant as compared to that observed without pretreatment (P<0.05). However, in the rectum, the secretory response to CCh and forskolin was abolished to a significant degree by indomethacin (P<0.05). Moreover, these indomethacin-induced changes were reversed by the addition of PGE2. Upon semiquantitative RT-PCR analysis, the amounts of cystic fibrosis transmembrane regulator, KCNQ1, and CLCA1 mRNAs were not found to be different between the two segments. CONCLUSION: There was a clear segmental heterogeneity with regard to electrogenic secretion in the human colon, and this difference can be explained by differences in the ascending colon and rectum.

Local transfer of prostaglandin E2 into the ovary and its retrograde transfer into the uterus in early pregnant sows.

This study was designed to establish (a) whether prostaglandin E2 (PGE2) can reach the ovary and oviduct by a local pathway and what is the contribution of lymphatic vessels to this transfer, and (b) whether PGE2 can permeate from venous and lymphatic vessels of the mesometrium to arterial blood and be delivered to the uterine horn during maternal recognition of pregnancy in gilts. The reproductive tract was excised from gilts (n = 10) on day 14 after mating. The uterine horn was isolated with the ovary and broad ligament and perfused with warmed and oxygenated autologous blood. A total dose of 5.5 x 10(7) disintegrations per min (d.p.m.) (49 ng) [3H]PGE2 was infused into the small branches of the uterine vein on the broad ligament or into the lymphatic vessels. Frequent blood samples were collected from the branch of the uterine artery and from the venous effluent. Tissue samples were collected from the uterine horn, the ovary and the broad ligament. The concentration of [3H]PGE2 was significantly higher in the ovary (P < 0.001), oviduct (P < 0.01), endometrium (P < 0.01), myometrium (P < 0.001) and mesometrium (P < 0.001) after infusion of [3H]PGE2 into lymphatic vessels than into the branches of the uterine vein. In contrast, the concentration of [3H]PGE2 was significantly higher in arterial blood supplying the uterine horn (P < 0.01) and in the venous effluent (P < 0.001) after infusion of [3H]PGE2 into the branches of the uterine vein than into lymphatic vessels. These results demonstrated local transfer of [3H]PGE2 into the ovary, oviduct and uterine horn from lymphatic and venous vessels of the mesometrium. However, the efficiency of this transfer was considerably higher after infusion into lymphatic vessels than into branches of the ovarian vein. We conclude that the lymphatic pathway is a fundamental mechanism in the local transfer of PGE2 from the uterus to the ovary and oviduct during early pregnancy in the pig.

The protective effect of rebamipide on paracellular permeability of rat gastric epithelial cells.

BACKGROUND: Barrier function in gastric epithelial cells is essential for the gastric defence mechanism against acid back-diffusion into the mucosal layer. Our previous study indicated that trans-epithelial resistance (TER) of rat gastric epithelial cells was rapidly increased when the cells were exposed to acid. This response to acid was diminished by indometacin. AIM: Evaluate the effects of a mucoprotective agent, rebamipide, on the nonsteroidal anti-inflammatory drug (NSAID)-induced increase of gastric epithelial permeability. METHODS: Rat gastric epithelial cells were plated on tissue culture inserts. Cells were exposed to a NSAID (indometacin, 10-7 M). Trans-epithelial permeability was measured by TER and diffusion rate of 14C-mannitol. The effect of rebamipide was evaluated by measuring TER. Endogenous prostaglandin E2 (PGE2) production in culture medium was also measured. RESULTS: Indometacin gradually and significantly decreased TER and increased 14C-manitol permeability. Rebamipide reversed the indometacin-induced changes in epithelial permeability and induced PGE2 synthesis. This induction was blocked by either indometacin or a Cyclooxygenase (COX)-2 specific inhibitor. CONCLUSIONS: COX inhibitors such as indometacin inhibit regulation of epithelial permeability by reducing PGE2. COX-1 has an important role in the gastric defense mechanism. Rebamipide suppressed an indometacin-induced increase in gastric epithelial permeability by increasing PGE2 levels in a COX-2 dependent manner.

Identification of lactate as a driving force for prostanoid transport by prostaglandin transporter PGT.

We previously characterized the prostaglandin (PG) transporter PGT as an exchanger in which [(3)H]PGE(2) influx is coupled to the efflux of a countersubstrate. Here, we cultured HeLa cells that stably expressed human PGT under conditions known to favor glycolysis (glucose as a carbon source) or oxidative phosphorylation (glutamine as a carbon source) and studied the effect on PGT-mediated [(3)H]PGE(2) influx. PGT-expressing cells grown in glutamine exhibited a 2- to 4-fold increase in [(3)H]PGE(2) influx compared with the antisense control, whereas cells grown in glucose exhibited a 14-fold increase. In the presence of 10 vs. 25 mM glucose during the uptake, there was a dose-dependent increment in [(3)H]PGE(2) influx. Cis inhibition of [(3)H]PGE(2) influx occurred with lactate at physiological concentrations (apparent K(m) = 48 +/- 12 mM). Preloading with lactate caused a dose-dependent trans stimulation of PGT-mediated [(3)H]PGE(2) uptake, and external lactate caused trans stimulation of PGT-mediated [(3)H]PGE(2) release. Together, these data are consistent with PGT-mediated PG-lactate exchange. Cells engaged in glycolysis would then be poised energetically for prostanoid uptake by means of PGT.

Cytokines and cytokine inducers stimulate prostaglandin E2 entry into the brain.

Cytokine inducers and cytokines increase the circulating level of prostaglandin E2 (PGE2) during the acute-phase immune response. This occurs simultaneously with the onset of fever, indicating that brain levels of PGE2 also increase. This raises the possibility that PGE2 produced in the peripheral circulation, not necessarily at distant sites from the brain, may penetrate the brain and be present in the cerebrospinal fluid (CSF). Blood and CSF levels of PGE2 in rabbits were measured by radioimmunoassay during fever stimulated in response to lipopolysaccharide (LPS), polyinosinic:polycytidylic acid (poly I:C) and interleukin-1 (IL-1) given i.v. The effect of the prostaglandin synthesis inhibitor ketoprofen on these parameters was also studied. In addition, the level of radioactivity in the CSF was measured following the administration of [125I]-labelled PGE2 i.v. during fever induced by LPS, poly I:C, IL-1 or tumor necrosis factor alpha (TNFalpha). Both LPS and poly I:C stimulated an increase in plasma and CSF levels of PGE2 over a 5-h period with a peak at 60 min and 90 min, respectively, which occurred in parallel with the changes in body temperature. Ketoprofen abolished the rise in plasma and CSF PGE2 levels and the rise in body temperature in response to LPS, poly I:C and IL-1. In experiments where animals were given [125I]-labelled PGE2 i.v., radioactivity well above the background level was measured in samples of CSF collected from LPS-, poly I:C-, IL-1- or TNFalpha-pretreated animals. In contrast the radioactivity present in samples of CSF perfusate collected from control (saline-treated) animals was indistinguishable from the background level. These data indicate that cytokine inducers and cytokines increase the mass level of PGE2 in blood and CSF and also increases the entry, from the peripheral circulation, of radiolabelled PGE2 into the third cerebral ventricle.

Functional analysis and androgen-regulated expression of mouse organic anion transporting polypeptide 1 (Oatp1) in the kidney.

Mouse Oatp1 was recently identified as a new murine member of the organic anion transporting polypeptide (Oatp) family and suggested to represent the counterpart of rat Oatp1. Northern blot analysis detected expression of several mouse Oatp-transcripts predominantly in liver and kidney. In the present study we describe the strict androgen-dependent expression of mouse Oatp1 mRNA in kidney and obtained further information about its substrate specificity using Xenopus oocytes. In addition to the previously reported estrone-3-sulfate, we demonstrate that mouse Oatp1 mediates sodium-independent uptake of the anionic steroid conjugates dehydroepiandrosterone sulfate (K(m) approximately 8 microM) and estradiol-17-glucuronide (K(m) approximately 5 microM) and also of the prostaglandin PGE(2).

Disruption of the blood-aqueous barrier following retinal laser photocoagulation and cryopexy in pigmented rabbits.

Disruption of the blood-aqueous barrier (BAB) induced by retinal photocoagulation and cryopexy in pigmented rabbits was evaluated by laser flare photometry. A significant increase in flare values after retinal photocoagulation was measured from the 1st postoperative day, with values returning to baseline levels by day 7. Cryopexy induced consistently high flare values for 14 days. Intravitreal injection of interleukin (IL) 1, IL-6 and prostaglandin (PG) E(2) induced a significant increase in flare values. Following these treatments, introduction of a PG synthetase inhibitor can partially ameliorate BAB disruption. IL-1, IL-6 and PGE(2) may be involved in BAB disruption following retinal photocoagulation and cryopexy.

Inducción de parto en pacientes con ruptura prematura de membranas en embarazos a término con dinoprostona versus oxitocina. Un estudio aleatorio / Delivery induction in patients with premature rupture of membranes in term pregnancy with Dinosprotone versus oxitocin. An aleatory study

Se realizó un estudio comparativo al azar para evaluar los efectos de la dinoprostona en el Hospital de Gineco Obstetricia No. 60 del Instituto Mexicano del Seguro Social, de junio a diciembre de 1997, en relación a la inducción de trabajo de parto en pacientes con embarazo de término, ruptura prematura de membranas y con índice de Bishop igual o menor a 4. Se estudiaron un total de 156 pacientes divididas en dos grupos: 78 pacientes a quienes se les adminsitró por vía vaginal gel con dinoprostona y a las restantes 78 se les administró oxitocina con la misma finalidad, éste último fue el grupo control. Los resultados encontrados fueron que la duración de la inducción con cinoprostona es de dos horas en promedio menor que con oxitocina (p>0.05). Se lograron 67 partos con dinoprostona y 65 partos con oxitocina, resultados que no son significativos. (p<0.06). El porcentaje de falla de inducción fue considerado en relación a la ausencia de modificaciones cervicales en 12 horas de administración de ambos fármacos, sólo hubo tres pacientes en cada grupo en estas condiciones. Las complicaciones observadas fueron las mismas y las condiciones del recién nacido fueron mejores en el grupo de dinoprostona. Las complicaciones infecciosas maternas fueron menores en el grupo de dinoprostona, y resultaron estadísticamente significativas (p>0.05). Se puede concluir que dinoprostona en aplicación intracervical acorta el tiempo de latencia de inducción-expulsión con mejores condiciones del recién nacido y menor procentaje de complicaciones infecciosas, en relación con el grupo control de oxitocina

Inducción del trabajo de parto en pacientes con ruptura prematura de membranas a término: oxitocina vs prostaglandina E2 de liberación controlada / Labour induction in patients who have premature rupture of membranes at term: oxytocin vs. vaginal E2-prostaglandine of controlled release

El propósito del presente estudio es comparar el uso de la oxitocina contra la seguridad de la aplicación de un óvulo de prostaglandina E2 de liberación controlada en la inducción del trabajo de parto, en pacientes de término con ruptura prematura de membranas y cervix no maduro (indice de Bishop ó 6) y comparar el tiempo de la aplicación al parto. Se trata de un estudio prospectivo, comparativo y al azar. Fueron 78 pacientes distribuidas al azar para recibir oxitocina intravenosa en el grupo 1 (n = 38) y prostaglandina (n = 40) en el 2. Se analizó el tiempo transcurrido desde el momento de la aplicación hasta el momento del parto y la presencia de complicaciones maternas y fetales. Las pacientes que recibieron prostaglandina E2 presentaron un menor tiempo desde su aplicación hasta el parto: 565.17 ñ 449 min. Comparado con el de oxitocina el cual fue de 988.33 ñ 916.38 min. (P = 0.001). Sólo fue necesaria, la aplicación de un óvulo. Las complicaciones durante el parto, su terminación, las complicaciones maternas y el desenlace neonatal fueron similares en ambos grupos. En conclusión, la aplicación de un óvulo de liberación controlada de prostanglandina E2 induce el trabajo de parto en forma segura y efectiva y reduce el tiempo de labor en comparación con la oxitocina. No se presentaron efectos adversos maternos ni neonatales

Electrogenic ion transport along the human duodenum in childhood.

BACKGROUND: To find reliable sites to study the effects of different secretagogues on electrogenic ion secretion, we investigated the secretion pattern in different parts of duodenum. METHODS: Histologically normal routine intestinal biopsy specimens from children were mounted in a modified Ussing chamber. The secretory responses to prostaglandin E2 (PGE2), aminophylline, dibutyryl cyclic adenosine 5'-monophosphate (cAMP), and acetylcholine (ACh) were studied with continuous measurements of the potential difference. Tissue resistance and generated current were calculated. RESULTS: ACh induced secretion in the whole of duodenum, although the secretory response was augmented distally. PGE2 and cAMP induced significant secretion only in the distal duodenum. CONCLUSIONS: The ACh-induced, calcium-mediated, electrogenic secretion was expressed along the whole duodenum, whereas the cAMP-mediated secretion was only seen in the distal part. The fully expressed electrogenic chloride secretion was only seen at or distal to the duodenojejunal flexure. Our study shows that it is important to carefully define the localization of physiologic studies performed in the duodenum.

Effect of intracervical administration of a prostaglandin E2 gel in pregnant and non-pregnant heifers.

The effects of prostaglandin E2 (PGE2) on cervical opening in non-pregnant and pregnant heifers was studied, and in the pregnant animals the effect on the embryo was studied by means of ultrasonography. In four consecutive experiments, 5 ml of saline, a gel containing 2 mg or 6 mg PGE2 was administered intracervically to four non-pregnant heifers, and 2 mg of PGE2 was administered to heifers pregnant 33 to 40 days. All the groups treated with PGE2 experienced an increase in the concentrations of prostaglandin metabolite in plasma (P < 0.05) shortly after administration, which reached a peak 15 to 30 minutes after administration. An increase in cervical opening was evident in all the PGE2-treated heifers (P < 0.05) from three hours after treatment. There was no difference between the effect of the two doses. The heifers which received saline did not show any significant changes. In addition, the treated heifers showed cervical softening, congestion and mucus secretion which were more pronounced in the pregnant heifers. The embryos were not affected. Plasma progesterone concentrations remained unchanged in all the experiments.

Eicosanoids regulate tumor necrosis factor synthesis after hemorrhage in vitro and in vivo.

The aim of this investigation was to determine whether PGE2 regulates TNF release in vitro and in vivo following hemorrhage. To study this, C3H/HeN mice were bled to a mean blood pressure (BP) of 35 mm Hg, maintained for 60 minutes, and then resuscitated. For in vitro studies, peritoneal (pM phi) and splenic (sM phi) macrophages obtained at 2 hours and 24 hours after hemorrhage were stimulated with LPS for 24 or 48 hours with or without ibuprofen (IBU). For in vivo studies, M phi were harvested 24 hours following hemorrhage with and without IBU treatment and stimulated with LPS for 48 hours. The decreased TNF release by pM phi but not sM phi from hemorrhaged mice was restored by IBU in vitro. IBU treatment in vivo significantly enhanced TNF release by pM phi compared with untreated hemorrhaged animals, while TNF release by sM phi was only slightly increased. These data indicate a major role of PGE2 in the regulation of TNF release by pM phi following hemorrhage.

Contraluminal p-aminohippurate transport in the proximal tubule of the rat kidney. VII. Specificity: cyclic nucleotides, eicosanoids.

Using the stop-flow peritubular capillary microperfusion method the inhibitory potency (apparent Ki values) of cyclic nucleotides and prostanoids against contraluminal p-aminohippurate (PAH), dicarboxylate and sulphate transport was evaluated. Conversely the contraluminal transport rate of labelled cAMP, cGMP, prostaglandin E2, and prostaglandin D2 was measured and the inhibition by different substrates was tested. Cyclic AMP and its 8-bromo and dibutyryl analogues inhibited contraluminal PAH transport with an app. Ki,PAH of 3.4, 0.63 and 0.52 mmol/l. The respective app. Ki,PAH values of cGMP and its analogues are with 0.27, 0.04 and 0.05 mmol/l, considerably lower. None of the cyclic nucleotides tested interacted with contraluminal dicarboxylate, sulphate and N1-methylnicotinamide transport. ATP, ADP, AMP, adenosine and adenine as well as GTP, GDP, GMP, guanosine and guanine did not inhibit PAH transport while most of the phosphodiesterase inhibitors tested did. Time-dependent contraluminal uptake of [3H]cAMP and [3H]cGMP was measured at different starting concentrations and showed facilitated diffusion kinetics with the following parameters for cAMP: Km = 1.5 mmol/l, Jmax = 0.34 pmol S-1 cm-1, r (extracellular/intracellular amount at steady state) = 0.91; for cGMP: Km = 0.29 mmol/l, Jmax = 0.31 pmol S-1 cm-1, r = 0.55. Comparison of app. Ki,cGMP with app. Ki,PAH of ten substrates gave a linear relation with a ratio of 1.83 +/- 0.5. All prostanoids applied inhibited the contraluminal PAH transport; the prostaglandins E1, F1 alpha, A1, B1, E2, F2 alpha, D2, A2 and B2 with an app. Ki,PAH between 0.08 and 0.18 mmol/l. The app. Ki of the prostacyclins 6,15-diketo-13,14-dihydroxy-F1 alpha (0.22 mmol/l) and Iloprost (0.17 mmol/l) as well as that of leukotrienes B4 (0.2 mmol/l) was in the same range, while the app. Ki,PAH of the prostacyclins PGI2 (0.55 mmol/l), 6-keto-PGF1 alpha (0.77 mmol/l) and 2,3-dinor-6-keto-PGF1 alpha (0.57 mmol/l) as well as that of thromboxane B2 (0.36 mmol/l) was somewhat higher. None of these prostanoids inhibited contraluminal dicarboxylate transport and only PGB1, E2 and D2 inhibited contraluminal sulphate transport (app. Ki,SO4(2-) 5.4, 11.0, 17.9 mmol/l respectively). Contraluminal influx of labelled PGE2 showed complex transport kinetics with a mixed Km = 0.61 mmol/l and Jmax of 4.26 pmol S-1 cm-1. It was inhibited by probenecid, sulphate and indomethacin. Contraluminal influx of PGD2, however, was only inhibited by probenecid. The data indicate that cyclic nucleotides as well as prostanoids are transported by the contraluminal PAH transporter. For prostaglandin E2 a significant uptake through the sulphate transporter occurs in addition.(ABSTRACT TRUNCATED AT 400 WORDS)

Transdermal absorption of radioprotectors in the rat using permeation-enhancing vehicles.

Topical radioprotection of rat skin with WR-2721 has not been effective presumably because the drug does not cross the stratum corneum to reach the epidermis and dermis. Earlier, we showed in the mouse that WR-2721 and cysteine dissolved in permeation-enhancing vehicles passed through the skin more readily than when in water. However, the most effective vehicles in the mouse were not necessarily as effective in the rat. Here we report that the most effective transport vehicles in the rat were (1) water with WR-2721, (2) water and dimethylformamide (DMF) with cysteine, and (3) water and DMF with prostaglandin E2 (PGE2). Pretreatment of the skin with dimethylsulfoxide (DMSO) further improved the transfer of the radioprotectors across the skin in most cases. After pretreatment with DMSO, the most effective vehicles were (1) water for WR-2721, (2) water and methyl-2-pyrrolidone (M-2-P) for cysteine, and (3) DMF for PGE2.

Interleukins 1 and 3 stimulate anion secretion in chicken intestine.

Interleukin 1 or 3 added to the serosal side of chicken small intestine transiently increases short-circuit current. Replacement of bathing-medium Cl and HCO3 with gluconate and HEPES abolished the short-circuit current increase, consistent with these cytokines stimulating electrogenic anion secretion. Cytokine-stimulated short-circuit current changes were inhibited by preincubation with piroxicam (10(-5) M), an inhibitor of arachidonic acid cyclooxygenase, suggesting prostaglandin formation as an intermediate step for cytokine stimulation of short-circuit current. In intact mucosal strips, interleukin 1 and 3 stimulated prostaglandin E2 release and elevated tissue 3',5'-cyclic adenosine monophosphate concentration. When prostaglandin E2 release from epithelial and subepithelial fractions of the mucosa by interleukin 1 was determined, increases were found only from the subepithelium. The secretory actions of cytokines appear to be mediated by arachidonic acid metabolites most likely produced by cells of the lamina propria and submucosa and may play a role in inflammatory processes in which intestinal secretion is enhanced.

Bone-resorbing agents promote and interferon-gamma inhibits bone cell collagenase production.

Parathyroid hormone, prostaglandin E2, 1 alpha,25-dihydroxyvitamin D3, interleukin-1, tumor necrosis factor alpha, and epidermal growth factor, all known stimulators of bone resorption, markedly enhanced collagenase secretion by rat fetus osteoblastlike cells in primary culture as judged by enzyme-linked immunosorbent assay. Untreated cells contained no immunostainable or extractable collagenase. Collagenase was detected in the treated cells and media only after 1-3 h of treatment, and there was no increment in collagenase activity when cells were treated in the presence of actinomycin D or cycloheximide. Cells secreted collagenase in a latent form and also elaborated collagenase inhibitor; chromatographic separation of collagenase from collagenase inhibitor and subsequent activation of the collagenase with trypsin yielded the active species in stimulated but not in unstimulated cells. The ability of individual prostanoids, among seven tested, to promote collagenase production correlated positively with their reported capacity to promote bone resorption. Interferon-gamma (IFN-gamma), a known resorption inhibitor, blocked the increment in collagenase production caused by all agents tested. These results indicate a close linkage between stimulation of bone resorption and collagenase production by osteoblastlike cells. Various resorption stimulators, including some not previously tested for effects on collagenase, augment the de novo synthesis and secretion of collagenase and act by an IFN-gamma-inhibitable mechanism.