The hepatic microsomal UDP-glucuronyltransferase (UDPGT) for p-phenyl benzoic acid (PPBA) in the developing fetus of rat was investigated. The kinetic properties of UDPGT in microsome of fetus changed during developmental period. The value of the V_max for PPBA and uridine 5'-phosphoglucuronic acid (UDPGA) per mg protein increased with the day of gestation, remarkably between the 19th and 21st day of gestation. The developmental profile of the V_max per g liver was similar to the V_max per mg protein. Whereas the V_max in whole liver showed repid increase during development comparing with the V_max per g liver. The K_m for PPBA and UDPGA showed slower increase with the day of gestation than the corresponding V_max.

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N⁴-Hydroxylation of sulfanilamide was studied with kidney and liver microsomes of rats by means of high performance liquid chromatography. In kidney microsomes, both contents of cytochrome P-450 (448) and activity of N⁴-hydroxylase were markedly increased by pretreatment with 3, 4, 5, 3', 4'-pentachlorobiphenyl (PenCB) (about 4 times), although neither one was increased by 3-methylcholanthrenen (3-MC) and phenobarbital (PB) pretreatments. In liver microsomes, on the other hand, both N⁴-hydroxylase activity and cytochrome P-450 (448) contents were increased by either PenCB or 3-MC pretreatment, whereas by PB pretreatment, N⁴-hydroxylase activity was not changed although cytochrome P-450 contents was increased 2-fold.

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Pyroglutamyl peptidase (EC 3.4.19.3 : L-pyroglutamyl peptide hydrolase, pyrrolidonecarboxylyl peptidase) was purified from chicken liver by a series of column chromatographies on DEAE-Sephadex A-50, PCMB-T-Sepharose, Sephadex G-150 and hydroxyapatite. By these procedures, the enzyme was purified about 3800-fold with an activity recovery of 3.6%. The enzyme was most active and stable at pH7-8.2. Mercaptoethanol and ethylene diaminetetraacetate (EDTA) were found to stabilize the enzyme effectively. The enzyme was inactivated by the incubation with sodium tetrathionate, PCMB, Ni²⁺, Cd²⁺, Zn²⁺ and Hg²⁺, but not affected by serine protease inhibitors such as diisopropylphosphoro fluoridate (DFP) and phenylmethanesulfonyl fluoride (PMSF). Thiolprotease inhibitors, E-64 and Ep-475, were partially inhibitory to the enzyme. The molecular weight of the enzyme was estimated to be 86000 by the gel filtration method and the isoelectroc point was at pH 5.5 as checked by isoelectric focusing method. The enzyme readily hydrolyzed pyroglutamyl-β-naphthylamide (Pyr-2-NNap), Pyr-p-nitroanilide (Pyr-pNA), Pyr-4-methylcoumarinamide (Pyr-MCA) and most of Pyr-amino acids tested, by was only slightly active toward Pyr-D-Ala and completely inert toward Pyr-Pro. Kinetic analysis of the reaction indicated that the latter two peptides competitively inhibit the enzyme reaction with K_i values of 7.8 and 13.5 mM, respectively. The K_m values of Pyr-derivatives of 2-NNap, MCA, pNA and Ala were 0.7, 0.04, 0.73 and 0.89mM, respectively. The enzyme split bradykinin potentiator, neurotensin, luteinizing hormone releasing hormone (LHRH), thyroliberin (TRH), frog litorin and physalaemin, liberating pyroglutamic acid from their amino termini, but was inactive toward uperolein and TRH-analogue, piperidone carbonyl His-Pro-NH₂.

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An enzyme immunoassay has been developed to measure human manganese-superoxide dismutase (Mn-SOD) in serum and urine. The assay can be done in less than 5 h, is highly sensitive (detecting limit, 0.1 ng of Mn-SOD) and simple. There is no interference from factors in serum or urine under assay conditions, and the method is specific for human Mn-SOD. Serum Mn-SOD concentrations were markedly increased in patients with liver diseases, but not in renal diseases. On the other hand, urinary Mn-SOD levels were elevated in a few patients with nephrotic syndrome and lung cancer, but were decreased in patients with hypertension. Furthermore, investigations were conducted on the clinical course of serum Mn-SOD levels in a case of alcoholic hepatitis, and on correlations between serum Mn-SOD and the conventional liver function tests. The localization of Mn-SOD in liver was also explored using immunofluorescent staining. The fluorescence was intense in the degenerated portions of liver tissue from a patient with drug-induced hepatitis.

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The effects of caffeine and thymol on the release of calcium from sarcoplasmic reticulum (SR) of mechanically skinned fibers isolated from semitendinosus muscle of frog, Xenopus laevis, are studied. Calcium release caused by caffeine is composed of two processes, a fast and a slow ones. The fast process is observable only when the amount of calcium stored in SR is above a "threshold" value while the slow one detectable only below the threshold value. The rate of these two processes does not depend on the concentration of caffeine so strongly, but the threshold value decreased as caffeine concentration is increased. On the contrary to this, calcium release produced by thymol is observed as a single rate process. More thymol results in increase in the rate of this process. The effects of these two kinds of drug on the uptake of calcium to SR are also studied. These two drugs give different effects on the calcium uptake, which are consistent with those actions of drugs on the calcium release. Procaine weakens the effects of these drugs. A simple model is given to explain the action of these two drugs on SR. The mechanisms of the drug action are also discussed in relation to the results obtained with the spin-label study.

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Aclacinomycin A (ACM) antisera were abtained from the rabbits immunized with 4'''-deoxo-4'''-(R)-amino-ACM-or N, N-didemethyl-ACM-bovine serum albumin conjugate, and their immunoreactivites were tested with ACM-related anthracyclines. It was found that the binding ability with the ACM antisera was markedly decreased by the following structural changes in ACM : N, N-didementhylation of the rhodosamine moiety ; 6-O-or 4-O-methylation ; removal of the methoxycarbonyl group at C-10 ; hydroxylation at C-1, C-2 or C-11. It was less affected by some alterations in a side chain at C-9 or by deglycosidation of the terminal mono or disaccharide. The binding of the aglycone (aklavinone) was very weak.

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We studied the uptake of radioactive 5-fluorouracil (FUra) by the intact cells of Ehrlich ascites tumor in the presence of various coreactants with FUra such as uridine (Urd), deoxyuridine (dUrd), ribose 1-phosphate (Rib1P), and deoxyribose 1-phosphate (dRib1P). Radioactivity uptake by the cells was increased when FUra-6-¹⁴C was incubated with Rib1P of dRib1P, while the uptake was not stimulated with Urd or dUrd. The increased formation of antineoplastic ribo- and deoxyribo-nucleotides of FUra in the acid-soluble fraction was also observed in the same incubation with Rib1P or dRib1P. Also, some detergents, ethylenediaminetetraacetic acid (EDTA), adenosine 5'-triphosphate (ATP), and polymines were examined. EDTA stimulated the uptake of radioactivity from the FUra by the cells. However, the other compounds exhibited no effect on the uptake of FUra alone or FUra plus dRib1P, except of ATP showing somewhat increase of radioactivity uptake. The above results suggest that the coadministration of FUra together with Rib1p or/and dRib1P, which are stimulants for the formation of FUra-deoxynucleotides from FUra, may be able to potentiate the chemotherapeutic effect of FUra.

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m-Aminobenzamide and benzamide, which are potent inhibitors of poly (adenosine diphosphate ribose) polymerase and have no antitumor activity themselves, potentiated the antitumor activity of bleomycin against Ehrlich ascites carcinoma in vivo.

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Effects of tripelennamine, N, N-dimethyl-N', N'-dibenzylethylenediamine (DBED) and N, N-dibenzyl-N', N'-dimethyl-1, 2-propanediamine (DBPD) on the isotonic contractions of isolated vas deferens of guinea pig were examined. These ethylenediamines, except DBPD, induced slight but significant increase in sensitivity of vas deferens to K⁺. Tripelennamine induced dose-dependent potentiation to epinephrine and norepinephrine, but tripelen-namine-induced augmentation of acetylcholine-contractions was weak and dose-independent. DBED potentiated both catecholamines and acetylcholine in dose-dependent way and in the same degree. The degree of DBPD-induced augmentation of epinephrine-and norepinephrine-induced contractions was dose-independent and much weaker than that of acetylcholine-contractions. Tripelennamine and DBED did not affect the contractile response to tyramine, while DBPD potentiated the contractile response to tyramine. These results suggest the following possibilities : 1) tripelennamine affects both amine uptake mechanism and beyond receptor mechanism of contractile processes and induced supersensitivity of various stimulants. 2) DBED affects mainly beyond receptor mechanism of contractile processes and augments the contractile responses to various stimulants. 3) The mechanism of DBPD-induced supersensitivity remained obscure, but the inhibition of the metabolic degradation of stimulants was proposed as one of the possible mechanism of supersensitization.

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A new experimental system with cultured gastric cells was developed to estimate the cytoprotective and damaging effects of drugs. The gastric cells were incubated in vitro in medium of pH 3, and their resistance to acid was determined by measruing percentage of damaged cells as a function of time. Pretretment with 0.5 mM acetylsalicylic acid (ASA) for 24 h decreased their resistance (26%), whereas pretreatment with 0.3-3 μg/ml of 16, 16-dimethylprostaglandin E₂ (dimethyl PGE₂) for 4 h increased their resistance (13-16%). The adenosine 3' : 5'-cyclic monophosphate (cyclic AMP) level in the cultured gastric cells was decreased by 0.5 mM ASA (30%) and increased by 0.3 μg/ml of dimethyl PGE₂ (38%) on treatment for 24 h. These changes reflect phenomena observed in the gastric mucosa, suggesting that this experimental system is valid as an in vitro model. Concentrations of 0.1 mM cyclic AMP and 0.1 mM N⁶, O^2'-dibutyryladenosine 3' : 5'-cyclic monophosphate (dibutyryl cyclic AMP) were found to exert cytoprotective effects on the cells (5 and 7% increase, respectively). Furthermore, 0.1 mM cyclic AMP caused partial recovery from 0.5 mM ASA-induced decrease in resistance (ASA : 17%, ASA+cyclic AMP : 9%). These findings suggest that cyclic AMP plays a role in protection of cultured gastric cells and presumably also of gastric mucosal cells in vivo.

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The present study demonstrated the metabolism of N-hydroxyurethane by cell-free preparations, i.e., 9000×g supernatant, cytosol and microsomes, from guinea pig livers. Under anaerobic conditions, the metabolizing activities of these preparations were enhanced markedly by addition of both an NADPH-or NADH-generating system and FAD. When the 30-45% ammonium sulfate fraction from liver cytosol was combined with liver microsomes or milk xanthine oxidase, the metabolic reaction of N-hydroxyurethane proceeded to a greater extent. Thin-layer chromatographic examination showed that urethane was only a metabolite formed from N-hydroxyurethane by these preparations.

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Anti-inflammatory properties of paeoniflorin and its derivatives were examined in experimental animals. Paeoniflorin, desbenzoylpaeoniflorin and new monoterpene glucoside 'paeonon' inhibited experimental contact hypersensitivities and passive cutaneous anaphylaxis reaction. Paeonon inhibited tissue swelling in the adjuvant arthritis, while paeoniflorin and its related compounds were ineffective in inhibiting non-allergic inflammatory response.

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In order to examine clinical potential for ecarazine, prazosin, phentolamine and hexamethonium to cause orthostatic hypotension in man, the effects of these drugs on the vasopressor reflexes induced by bilateral carotid artery occlusion (BCO) or head-up tilting (Tilt) have been investigated in gallamine-immobilized cats. Ecarazine at doses of 0.1 to 10 mg/kg i.v. decreased blood pressure in a dose-dependent way whereas at 0.1 at 1 mg/kg it did not affect the pressor rsponse to BCO or Tilt and at 10 mg/kg it supressed only the response to BCO slightly. On the other hand, prazosin, phentolamine and hexamethonium, at hypotensive doses, not only decreased blood pressure but also inhibited pressor responses to both BCO and Tilt. Because ecarazine lacks in producing orthostatic hypotension, it seems likely that the clinical propensity of drugs to cause such side effect is correlated with the inhibition of Tilt response rather than with that to BCO. The results of comparison of the inhibition by these drugs of Tilt response indicate that ecarazine is the most favorable drug among these four drugs and that phentolamine has the highest incidence of orthostatic hypotension. With respect to the effects of prazosin, phentolamine and hexamethonium, statistically significant correlation between the inhibition of the response to BCO and that to the compensatory reflex to Tilt has been observed. Hence it is suggested that the agents which decrease blood pressure by affecting peripheral sympathetic mechanisms might depress each efferent sympathetic pathway to the same degree.

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High concentrations of propranolol (10^-5-3×10^-4M) inhibited in a dosedependent fashion and reversibly the maximal contractile responses produced by 150 mM K⁺ in the rat vas deferens. 10^-4M propranolol and quinine produced similar inhibitory effects on the dose-response curves to K⁺. Since norepinephrine-induced contractions were not substantially inhibited by quinine or propranolol, it was suggested that the two drugs may specifically inhibit the potassium-induced inflow of external calcium.

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