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We investigated the attractiveness of a synthetic form of the pheromone of the soybean stink bug, Piezodorus hybneri (Gmelin), under field conditions, and compared it with that of (E)-2-hexenyl (E)-2-hexenoate, a pheromone component of a competitor, Riptortus pedestris (Fabricius). Many adult stink bugs were attracted to traps baited with 100 mg of the synthetic pheromone (1: 1: one mixture of β-sesquiphellandrene, (R)-15-hexadecanolide, and methyl (Z)-8-hexadecenoate), but few were attracted to 1 or 10 mg. More than twice as many females as males were attracted to this male-produced pheromone. None of the individual pheromone components (30 mg) attracted conspecifics. In summer (June-July), when field P. hybneri were not in diapause, (E)-2-hexenyl (E)-2-hexenoate was more attractive to P. hybneri than the synthetic pheromone. The sex ratio of the adults attracted to the synthetic pheromone was highly female-biased, yet almost equal numbers of both sexes were attracted to (E)-2-hexenyl (E)-2-hexenoate. Most females attracted to both attractants were mated and had mature ovaries. However, adults attracted to (E)-2-hexenyl (E)-2-hexenoate were likely to have less food in their stomach than those attracted to the synthetic pheromone. In late autumn (October-November), when the bugs were in reproductive diapause, both attractants attracted many sexually immature female and male adults that had well-developed fat body. The synthetic pheromone also attracted a large number of conspecific nymphs. These results suggest that P. hybneri pheromone and R. pedestris pheromone component, respectively, have different functions for P. hybneri. The male-produced pheromone system of P. hybneri seems to be sex-related but to have other roles.

The chronic toxicity of enzymatically decomposed rutin, which consists mainly of isoquercitrin, was evaluated in male and female Wistar rats with dietary administration at concentrations of 0%, 0.04%, 0.2%, 1% and 5% for 52 weeks. No toxicological findings were found in the mortality, body weights, food consumption, hematology, clinical biochemistry or organ weights in either sex. Obvious clinical signs were chromaturia that could be attributed to the color of test substance in the 5% groups of both sexes. Coloration of the urine collected over 24h in the 1% and 5% groups of both sexes was noted. Increased daily urinary calcium excretion was observed in the 5% groups of both sexes and an increase in urinary calcium concentration was observed in the male 5% group. On histopathological examination, incidences of mineralization, inflammatory cell debris, inflammatory cell infiltration and/or transitional cell hyperplasia in the renal pelvis were increased in the 5% male group, whereas treated females showed no apparent difference in these incidences. Based on the above findings, the no observed adverse effect level (NOAEL) was estimated to be 1% in both sexes (542.4 mg/kg body weight/day for males and 674.0mg/kg body--weight/day for females).

Gene therapies may be promising for the treatment of peritoneal fibrosis (PF) in subjects undergoing peritoneal dialysis (PD). However, a method of delivery of treatment genes to the peritoneum is lacking. We attempted to develop an in vivo small interfering RNA (siRNA) delivery system with liposome-based nanoparticles (NPs) to the peritoneum to inhibit PF. Transforming growth factor (TGF)-β1-siRNAs encapsulated in NPs (TGF-β1-siRNAs-NPs) dissolved in PD fluid were injected into the peritoneum of mice with PF three times a week for 2 weeks. TGF-β1-siRNAs-NPs knocked down TGF-β1 expression significantly in the peritoneum and inhibited peritoneal thickening with fibrous changes. TGF-β1-siRNAs-NPs also inhibited the increase of expression of α-smooth muscle actin-positive myofibroblasts. These results suggest that the TGF-β1-siRNA delivery system with NPs described here could be an effective therapeutic option for PF in subjects undergoing PD.

Large abdominal wall defects may require a prosthesis for closure. The aim of our study was to identify the best material for abdominoplasty in pediatric patients. One hundred twenty-eight Wistar KY strain male rats (3 weeks old) were used. All animals underwent celiotomy via a midline skin incision. They were divided into seven groups as follows: the animals in groups 1 through 6 underwent full-thickness abdominal wall excision 3 cm in diameter. The animals in group 1 underwent primary closure. In groups 2 through 6 the defect was closed with prosthetic material. In Group 7, a sham operation was performed. Daily weights were measured. The animals were killed after 3 and 9 weeks. Adhesion scores were assigned for each group. Vicryl mesh resulted in the fewest adhesions and had no effect on weight gain in the developing rats.

Nuclear factor (NF)-κB is a transcription factor that regulates cytokine and chemokine production in various inflammatory diseases, including bronchial asthma. IκB kinase (IKK) β is important for NF-κB activation in inflammatory conditions, and is possibly related to airway remodelling. Thus, inhibition of the IKKβ-NF-κB pathway may be an ideal strategy for the management of airway remodelling.We examined the effects of a newly synthesized IKKβ inhibitor, IMD-0354, in a chronic allergen exposure model of bronchial asthma in mice.A chronic mouse model was generated by challenge with house dust mite antigen (Dermatophagoides pteronyssinus). IMD-0354 was administrated intraperitoneally in therapeutic groups. Lung histopathology, hyperresponsiveness and the concentrations of mediators and molecules in supernatants of lung homogenates were determined.NF-κB activation was inhibited by prolonged periods of IMD-0354 administration. IMD-0354 reduced the numbers of bronchial eosinophils. IMD-0354 also inhibited the pathological features of airway remodelling, including goblet cell hyperplasia, subepithelial fibrosis, collagen deposition and smooth muscle hypertrophy. Inhibition of these structural changes by IMD-0354 was the result of the suppressing the production and activation of remodelling-related mediators, such as TGF-β, via inhibition of IKKβ. IMD-0354 inhibited IL-13 and IL-1β production, and it restored the production of IFN-γ. It also ameliorated airway hyperresponsiveness.IKKβ plays crucial roles in airway inflammation and remodelling in a chronic mouse model of asthma. A specific IKKβ inhibitor, IMD-0354, may be therapeutically beneficial for treating airway inflammation and remodelling in chronic asthma.

Synthesis and activity of the enzymatic equivalent of the sodium pump, Na,K-ATPase, are regulated by thyroid hormone in responsive tissues. The purpose of this study was to determine whether triiodothyronine (T3) regulates the level of the messenger RNA (mRNA) coding for Na,K-ATPase alpha- and beta-subunits in the heart. The expression of Na,K-ATPase mRNAs in in vitro myocardial cells was directly assayed by Northern and slot blot hybridization using Na,K-ATPase alpha- and beta-isoform-specific cDNA probes. Exposure of cultured neonatal rat cardiocytes to 10(-8) M T3 resulted in 1) threefold to fourfold increase in alpha 1- and beta 1-mRNA accumulation, with a maximum elevation at 48 hours, 2) sevenfold increase in alpha 2-mRNA accumulation with a peak elevation at 72 hours, and 3) transient threefold increase in alpha 3-mRNA within the first 24 hours followed by a deinduction thereafter. The increase in alpha 1-mRNA accumulation by T3 occurred over the physiological T3 concentration range with an EC50 of 5 x 10(-10) M. This was associated with a twofold increase in alpha 1-subunit protein accumulation and an increase in Na,K-ATPase transport activity. The half-life of alpha 1-mRNA analyzed by actinomycin D chase was less than 3 hours and was not affected by T3. Transfection experiments with the luciferase reporter gene revealed that thyroid hormone response sequences are located within the 5'-flanking regions of each alpha-isoform gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Microelectrode techniques were used to determine the Na+ and K+ transport properties of the collecting duct cell in the isolated cortical collecting duct (CCD) from rabbits 14 d after uninephrectomy (UNX); results were compared with those from sham-operated rabbits (control). UNX had no effects on plasma aldosterone levels. The CCDs from UNX rabbits exhibited structural hypertrophy. The lumen negative transepithelial voltage and the basolateral membrane voltage (VB) were elevated in the UNX group. Although the transepithelial conductance (GT) and the fractional apical membrane resistance (fRA) were not different between the two groups, the conductances of the apical and the basolateral membranes were increased, and the tight junction conductance was decreased in the UNX group. The amiloride-sensitive changes in apical membrane voltage (VA), fRA, and GT were greater in the UNX group. The changes in VA upon raising the perfusate K+ concentration and the changes in VA and GT upon addition of Ba2+ to the perfusate were elevated in the UNX group. Upon raising K+ in the bath, a large depolarization of VB was observed in the UNX group. Lowering the bath Cl- resulted in a small depolarization of VB in the UNX group. Addition of Ba2+ to the bath in the UNX group caused the VB to hyperpolarize in parallel with decreases in GT and fRA whereas in the control group it had no effect on VB. Addition of ouabain to the bath resulted in a large depolarization of VB in the UNX group. We conclude that (a) UNX stimulates conductances of Na+ and K+ in the apical membrane, active Na(+)-K+ pump activity, and K+ conductance in the basolateral membrane, independently of plasma aldosterone; (b) The basolateral membrane in the tubules of UNX rabbits is more selective to K+; and (c) the hyperpolarization of VB upon UNX may increase passive K+ entry into the cell across the basolateral membrane.

Insulin secretion from MIN6 cells (a pancreatic beta-cell line) induced by high glucose (greater than 16.8 mM) was potentiated by a novel hypoglycemic agent [trans-4-(4-methylcyclohexyl)-4-oxobutyric acid (JTT-608)] (but not glibenclamide, a sulfonylurea). The extracellular Ca(2+)-free condition, a L-type Ca(2+) channel blocker (nifedipine) and an ATP-sensitive K(+) channel opener, diazoxide, completely inhibited increases in cytosolic free Ca(2+) ([Ca(2+)]i) and insulin secretion evoked by JTT-608 in the presence of extracellular Ca(2+). An electrophysiological study using single-barreled microelectrode techniques demonstrated that membrane potential (V(m)) and input resistance of the cell membrane (R(i)) are depolarized and increased by JTT-608, respectively. The apparent transference number for K(+) was also significantly decreased after the addition of JTT-608. These effects immediately occurred after addition of JTT-608 and very rapidly disappeared after removal of JTT-608, which has not been observed in sulfonylureas. Also, these effects of JTT-608 were diminished, but not completely by diazoxide. JTT-608 did not affect the specific binding of [(3)H]glibenclamide to the sulfonylurea receptor. These findings suggest that JTT-608 mainly inhibits ATP-sensitive K(+) channel activity via a binding site distinct from the sulfonylurea receptor and then depolarizes V(m) to open voltage-dependent L-type Ca(2+) channels. Subsequently, these events stimulate Ca(2+) entry to increase [Ca(2+)]i and induce insulin secretion from MIN6 cells. Therefore, JTT-608 is a unique hypoglycemic agent that enhances high glucose-induced insulin secretion. The present findings indicate that JTT-608 is a more useful new class of therapeutic drug for patients with non-insulin-dependent diabetes mellitus, compared with sulfonylurea derivatives.

Thiazolidinedione derivatives, new insulin-sensitizing antidiabetic agents, are expected to have potential clinical use. Since these drugs cause edema in a variable proportion of patients, we examined whether troglitazone (Tro) has direct action on Na+ transport of rabbit proximal straight tubule perfused in vitro. For this purpose, we measured basolateral membrane voltage (V(B)) by conventional microelectrode techniques and intracellular pH (pH(i)) by microscopic fluorescence spectrophotometry with a pH-sensitive fluorescent dye, 2', 7'-bis-2-carboxyethyl-5-carboxyfluorescein. Tro at 50 microM in the bath significantly depolarized both transepithelial voltage and V(B). To examine whether the basolateral rheogenic Na+/HCO3- cotransport activity is affected by Tro, we observed V(B) deflection upon abrupt 10-fold decrease in bath HCO3- in the absence and presence of Tro. The apparent transference number of HCO3- (tHCO3), as calculated from the V(B) deflection, was significantly greater in the presence of Tro (50 microM) than that seen in its absence. Tro caused cell acidification and increased the intracellular acidification rates (dpH(i)/dt) upon abrupt 10-fold decreases in bath HCO3- and Na+ concentrations. The stimulatory effects of Tro on tHCO3 and dpH(i)/dt were dose dependent between 5 and 50 miccroM, but they were unaffected at 0.5 microM. From these results, we conclude that Tro acts on the proximal straight tubule and stimulates the basolateral rheogenic Na+/HCO3- cotransport activity. The stimulatory action of Tro may partly account for edema formation.

Acute as well as chronic exposure of cadmium (Cd) leads to proximal tubule injury. The exact cellular mechanism of this disorder and whether there is a contribution of cadmium-metallothionein (Cd-MT), a binding protein of Cd, remain unclear. We perfused isolated S2 segments of rabbit nephron, and the deflections of transmural voltage (DeltaV(t)) and apical membrane voltage (DeltaV(a)) on elimination of glucose or alanine from the perfusate were measured for the parameters of activity of Na(+)-glucose and Na(+)-amino acid cotransporters. The effects of Cd-MT or CdCl(2) to either bath or lumen for 10 min on these parameters were examined. We also measured the lumen-to-bath [(14)C]glucose flux. Addition of Cd-MT to lumen suppressed glucose- or alanine-dependent DeltaV(t) and DeltaV(a), as well as baseline V(t) and basolateral membrane voltage (V(b)), at approximately 10 min. [(14)C]glucose flux was inhibited by Cd-MT to lumen. The effects of Cd-MT to bath and CdCl(2) to either lumen or bath were 100-fold less potent than that of Cd-MT to lumen. Luminal Cd-MT immediately suppressed the glucose-dependent DeltaV(a), whereas the baseline V(a) and V(t) were unchanged. The early effect of luminal Cd-MT was simulated by addition of 10(-4) M phloretin. Addition of 10(-4) M ouabain to the bath simulated the later effect of Cd-MT. The protection of SH group by dithiothreitol prevented the early effect of Cd-MT, but not the later effect. We concluded that Cd-MT initially acts directly on Na(+)-glucose and Na(+)-amino acid cotransporters from the lumen by attacking SH group, followed by the later inhibition of Na(+)-K(+)-ATPase after entering the cell from the apical membrane.

To further characterize the alpha- and beta-intercalated cells (alpha-IC, beta-IC) in the isolated and perfused connecting tubule (CNT), cortical collecting duct (CCD) and outer medullary collecting duct in the inner stripe (OMCDi) of rabbit kidneys, we studied the effects of various transport inhibitors on electrical parameters. They included inhibitors of Cl-/HCO3- exchanger (4-acetamino-4'-isothiocyanostilbene-2,2'-disulfonic acid, SITS), carbonic anhydrase (acetazolamide) and Na(+)-K(+)-ATPase (ouabain). Upon addition of 10(-3) M SITS to the bath, the basolateral membrane voltage (VB) of alpha-IC in the OMCDi and CCD was significantly hyperpolarized by 20.8 +/- 4.6 (n = 5) and 29.8 +/- 5.6 mV (n = 11), respectively. On the other hand, luminal addition of SITS had no effects on VB of alpha-IC in the OMCDi and CCD. Neither bath nor lumen SITS affected VB of beta-IC in the CCD and CNT. When 10(-4) M acetazolamide was added to the bath, VB of alpha-IC in the OMCDi and CCD was significantly hyperpolarized by 20.0 +/- 4.1 (n = 4) and 18.6 +/- 1.7 mV (n = 3), respectively. Similarly, 10(-4) M acetazolamide in the bath caused the basolateral membrane of beta-IC in the CCD and CNT to hyperpolarize significantly by 34.3 +/- 7.9 (n = 6) and 21.6 +/- 2.9 mV (n = 3), respectively. Luminal addition of acetazolamide had no effect on VB of alpha-IC in the CCD and OMCDi and beta-IC in the CCD and CNT.(ABSTRACT TRUNCATED AT 250 WORDS)

K18 (3-[p-(N,N-bis(2'-chloroethyl)amino)- phenyl]-L-alanine conjugated with human immunoglobulin) is a newly developed antitumor agent. LD50 values of K18 in animals were quite high, suggesting its low acute toxicity. This drug showed anti-tumorigenicity not only on an experimental animal tumor (Walker 256), but also on a human tumor transplantable into nude mice (RCC-13). A distribution study clarified the unique properties of K18 to accumulate and remain in the tumor site with a high rate.

We used liquid ion exchanger and conventional microelectrodes to evaluate the effects of mineralocorticoids on the intracellular K activity (aiK) and K transport properties of principal cells (PC) of isolated cortical collecting ducts (CCDs). Hoffman modulation optics and electrophysiological methods were used to identify PC. K activity was measured with two single-barreled electrodes. We found that aiK of PC from deoxycorticosterone acetate (DOCA)-treated rabbits (97.6 mM) was not different from controls (94.8 mM). The driving forces for K transport across the basolateral membrane favored cell to bath (reabsorption) in PCs from controls and bath to cell (secretion) in PCs from DOCA-treated rabbits. However, the driving force for K secretion across the apical membrane was not significantly different between the two groups. We used the intracellular aiKs and bath ion substitutions (gluconate for Cl and K for Na) to evaluate the effects of DOCA on the ion-selective properties of the basolateral membrane of PC. DOCA increased PK/PCl from 0.33 to 0.89. Our conclusion was as follows: in PC of control rabbits K is above electrochemical equilibrium across the basolateral membrane. However, the basolateral K conductance is probably too small for significant K recycling. In PC of DOCA-treated rabbits the aiK is below electrochemical equilibrium across the basolateral membrane and the K conductance is increased. These effects enhance K secretion across this border while maintaining cell K constant.

Electrophysiological and chemical methods were used to determine the Na and K transport properties of the isolated cortical collecting duct (CCD) of control and adrenalectomized (ADX) rabbits. Net fluxes of Na (JNa) and K (-JK) in controls were 5.7 and 3.2 pmol . mm-1 . min-1 and in ADX were 1.0 and 0.7 pmol . mm-1 . min-1, respectively, similar to electrically determined rates. In separate experiments, blind impalement of cells from adrenal intact (group 1), ADX (group 2), and ADX rabbits treated with deoxycorticosterone (group 3) allowed identification of two distinct cell types, majority cells (MA) and minority cells (MI). In all groups, MA were distinguished from MI by a relatively high basolateral membrane potential (-Vb), low apical membrane fractional resistance (FRa), and presence of apical and basolateral membrane K conductances. Vb of MA (-82.4 mV) was significantly hyperpolarized in groups 1 and 3 combined, when compared with group 2 (-66.4 mV). However, there was no significant difference between Vb of MI in group 2 (-38.9 mV) and Vb of MI in groups 1 and 3 (-36.2 mV). In MA of group 1 equivalent circuit values of apical membrane Na and K conductances (GNaa, GKa) and maximum pump current (Ipmax) were 0.84 and 6.72 mS/cm2 and 46.7 microA/cm2, respectively. These values in group 2 were significantly lower (0.28 and 1.52 mS/cm2 and 8.7 microA/cm2, respectively). It is concluded that two cell types can be distinguished electrically in the CCD. MA have properties consistent with principal cells and MI have properties consistent with intercalated cells. ADX causes a decrease in GNaa, GKa, and Ipmax of PC that results in proportionate decreases in INaa and IKa.

The cortical collecting tubule is one of the main nephron sites where mineralocorticoids and a high potassium diet modulate sodium (Na) and potassium (K) transport. In this study we explored the steroid-independent effects of a high K diet on the electrical transport properties of the isolated rabbit cortical collecting tubule principal cells. The electrophysiological analysis included transepithelial and single-cell potential measurements and equivalent circuit analysis. Rabbits were adrenalectomized (ADX) and received either a control diet (300 meq K/kg diet) or a high K diet (600 meq/kg diet) for 10 d before the experiment. The mean plasma K of ADX control animals was 6.9 mM, that of ADX animals on the high K diet 8.3 mM. The transepithelial potential difference was significantly elevated in the high K group (-3.5 mV, lumen negative), compared with ADX controls (-1.4 mV). The basolateral membrane potential in high K animals was also significantly elevated (-73 mV, cell negative, compared with -63 mV in controls). Estimates of the apical membrane partial Na and K conductances (GaNa and GaK) and of ion currents (IaNa and IaK) also demonstrated stimulation by the high K diet. In the high K group, both GaNa and GaK (0.56 and 2.67 mS.cm-2) were higher than control values (0.27 and 1.17 mS.cm-2). IaNa and IaK were also higher in high K animals (47.8 and -26.2 microA.cm-2) compared with control animals (22.4 and -11.6 microA.cm-2). Thus, a high K intake per se can induce electrophysiological changes consistent with stimulation of Na reabsorption and K secretion.

The cell-to-cell interaction between osteoclasts and fibroblast-like cells, which were mechanically disaggregated from long bones of neonatal rabbits, was investigated to clarify the cellular mechanisms responsible for the regulation of osteoclastic bone resorption by using phase-contrast time lapse recording and fluorescent microscopy for visualization of F-actin cytoskeleton. Osteoclasts showed rapid extension and retraction of pseudopodia with intense ruffling activity and active translocation over a glass surface when there was enough open space around them, while fibroblast-like cells seemed much more stationary. Osteoclasts were not able to cross over cell bodies of fibroblast-like cells which interfered with migration of the osteoclasts. As fibroblast-like cells proliferated, they gradually took over the open glass surface and finally tightly surrounded the osteoclasts. Such osteoclasts usually became contracted and pseudopodial and migratory activities decreased. Fluorescent microscopy of well-spread osteoclaststs stained with rhodamine-labeled phalloidin revealed development of a band-like structure composed of a number of brightly fluorescent F-actin dots at the cell periphery and fine F-actin bundles which run through the cell bodies. On the other hand, contracted osteoclasts tightly surrounded by fibroblast-like cells showed conglomerates composed of accumulated F-actin dots instead of the band-like structure. An F-actin pattern of fibroblast-like cells, which was very different from that of osteoclasts, displayed thick and straight bright bundles with in the cell bodies. The present observation suggests that ongoing osteoclastic bone resorption may be regulated by fibroblast-like cells through limitation of osteoclastic motile activity, and alteration of cytoskeleton and cell-substratum interaction which occurred in osteoclasts may be involved in the mechanism.

Adhesion variants can be isolated from suspension growing highly metastatic murine ESb tumor cells under reproducible conditions from uncloned as well as from cloned ESb tumor cells. One such variant, ESb-MP, has been analyzed in detail. In vitro it had similar growth properties and high invasive capacity as the parental ESb cells. In vivo, ESb-MP cells showed a reduced growth capacity as compared to ESb cells. This was seen at the site of tumor cell transplantation (increased latency period) as well as at the site of secondary tumor growth in internal organs. ESb-MP tumor cells disseminated much later than ESb cells from the primary tumor into the blood stream. Both tumor lines metastasized to the liver but they affected liver functions in a different way: ESb cells infiltrated the liver diffusely and exerted toxic effects on liver parenchyma very quickly. This resulted in early increase of liver enzyme activity in the blood. In contrast, liver infiltrated by ESb-MP cells showed a more focal type of colonization and the organs seemed to be functioning for much longer periods. In fact, animals inoculated with ESb-MP cells subcutaneously or intravenously had an increased life expectancy compared to ESb-tumor-bearing animals of about 300%. The organotropism of both tumor lines remained similar although there were kinetic and quantitative differences, especially with regard to the kidney. In late stages of tumor growth, ESb-MP-tumor-bearing animals developed a high percentage of metastases in the kidney and around and within the spinal cord, thereby causing a syndrome of hind-leg paralysis. This syndrome was remarkable in its reproducibility, especially after intravenous tumor cell inoculation. The changed adhesiveness thus seemed to have affected the tumor latency period, the speed of dissemination into blood and internal organs, the mode of organ infiltration (focal vs. diffuse) and of metastatic growth, parameters which all might contribute to the greatly reduced overall malignancy.

A new type of chemiluminescence (CL) was observed in thioglycolate-elicited ICR mouse peritoneal macrophages which had been incubated for 24 h in medium containing lymphokines (LK) and lipopolysaccharides (LPS), and then exposed to a CL reagent solution containing luminol and phorbol myristate acetate (PMA). The new CL, which was clearly distinguishable from PMA-induced CL, appeared immediately after the addition of the CL reagent solution, reaching a maximal level at about 30 s, and disappeared rapidly. We have called the new CL 'spontaneous CL', since it appeared spontaneously without PMA triggering. When the macrophages were incubated with LK in the presence of 10 ng/ml of LPS, the spontaneous CL began to appear after about 4 h incubation, the maximal level being reached at about 12 h, after which it decreased gradually on further incubation. After 48 h, it could not be observed at all. The spontaneous CL could be observed only in macrophages simultaneously treated with LK and LPS, as in the case of cytotoxicity. The correlation between spontaneous CL and cytotoxicity was suggested by the following; they showed a similar dose dependency to LK, and neither of them could be induced in aged macrophages which had been incubated in vitro for 1 day before exposure to LK and LPS. These results suggest that spontaneous CL measurement could possibly replace the cytotoxicity test as a simple method for the determination of macrophage activating factor.

Microelectrode methods were used to assess the Na-dependent effects of mineralocorticoids on the conductive transport properties of cortical collecting ducts (CCD) from adrenalectomized (ADX) rabbits. Rabbits were divided into four groups: control, 3 h treatment with deoxycorticosterone (DOCA), 18 h DOCA treatment, and 18 h DOCA plus amiloride treatment. After only 3 h of DOCA treatment the transepithelial potential (VT) increased significantly from -1.4 to -8.7 mV, and after 18 h VT increased further to -19.3 mV. The basolateral membrane potential (Vb) significantly increased after 18 h (from -61.6 to -87.6 mV). However, compared with treatment with DOCA alone for 18 h, both -VT and -Vb were significantly attenuated with DOCA plus amiloride treatment to -8.3 and -72.9 mV, respectively. The apical membrane Na and K currents (INaa and IKa) and conductances (GNaa and GKa) were all increased after 3 h DOCA treatment. After 18 h of DOCA treatment, IKa, INaa, and GKa increased further, but GNaa remained unchanged. On simultaneous treatment with DOCA and amiloride, the maximum pump current (Ipmax), IKa, INaa, and GKa but not GNaa were all reduced significantly. These results support a mechanism whereby mineralocorticoids first increase GNaa. A rise in cell Na results then in the simultaneous increase in GKa and sodium transport, probably by insertion of new Na pumps. An additional direct effect of DOCA on GKa and Ipmax is not excluded.

The effects of PSK on hepatic drug-metabolizing enzymes were investigated using Sarcoma 180-bearing and non-tumor-bearing ICR mice. PSK, an immunomodulator, has been commonly used in combination with tegafur for post-operative adjuvant chemotherapy. Tegafur is a typical masked compound transformed into 5-FU by the hepatic drug-metabolizing enzyme P-450. It has been reported that immunostimulants such as BCG and anaerobic Corynebacterium suppress the drug metabolism. PSK and Propionibacterium acnes were administered to mice inoculated s.c. with Sarcoma 180. It was demonstrated that Propionibacterium acnes had an effect of inhibiting these enzymatic activities, especially the amount of P-450 and cytochrome b5 and aminopyrine demethylation. On the other hand, PSK had no influence on the drug-metabolizing enzymes. Propionibacterium acnes was shown to decrease the 5-FU level in organs and sera of mice given FT-207 orally. By contrast, PSK showed no difference in 5-FU level compared to controls, indicating that PSK had no inhibitory effect on the activation of FT-207 by hepatic drug-metabolizing enzymes.