The deoxyribonucleic acid (DNA) duplex shows polyphorism depending on the base sequence and the environment. The base sequence dependent variations in conformational properties of the synthesized oligonucleotides are studied by X-ray analysis and several physico-chemical techniques. The possible structures in solution were proposed by molecular dynamics (MD) simulation. 1) The several oligonucleotides which include the adenine or adenine-thimine tract, have unique conformational characteristics with the base sequence dependent property. The junction-model structure for DNA bending was proposed by the combined method of nuclear magnetic resonance (NMR) observations and MD calculation. 2) The two different hydrogen bonding schemes of inosine-adenine base-pairing, anti/anti and anti/syn forms, are adopted in B-DNA structure. The preference of these forms depends on the base sequence. The MD calculation could offer the models consistent with NMR evidence. 3) Oligonucleotides containing cyclonucleosides with a high-anti (intermediate between anti and syn) glycosydic conformation adopt left-handed double-helical structures. A suitable model of this left-handed duplex was proposed by calculation with energy minimization.
To investigate the metabolic pattern of such a drug having two counter functional groups in the molecule : a hydrophylic sulfate group and a hydrophobic aromatic ring, as 17-sulfate of 17β-hydroxyestra-1, 3, 5 (10)-triene (3-deoxyestradiol) was incubated with rat hepatic microsomes under a reduced nicotinamide adenine dinucleotide phosphate-generating system. The metabolites assigned were mono-and dihydroxylated products hydroxylated only at the aromatic ring. The phenolic products having hydroxyl group at the position 2, 3, or 4 were detected in the male and female rats. The two catechol products having hydroxyl groups at 2, 3 and 3, 4 were detected only in the male rats. No other metabolites were formed except a phenol product hydroxylated at the position 1 in the case of the male rats. These metabolisms were confirmed to proceed without removal of the sulfate group. A simple method for the determination of these metabolites was established by using reversed-phase high-performance liquid chromatography. The devised technique involves an elution with a mixture of 0.5% NH4H2PO4 (pH 3.0) and methanol on a TSK-Gel ODS-120A column with electrochemical and/or ultraviolet detectors.
In order to investigate the antigenic effects of the carboxyl group in the side chain and the bridge length on producing anti lithocholic acid antibody, the immunogens in which bile acid is coupled with bovine serum albumin through propionyloxy or butyryloxy amide linkage at the C-6 position were prepared. The antibodies elicited by these conjugates had low titers but showed a high affinity for lithocholic acid with association constants in the range of 0.42-1.04×108 M-1. The cross-reactivities of both antisera were essentially the same as that of methyl 6α-hemisuccinyloxylithocholate. These results suggested that the side chain hydrolysis product of the methylated antigen worked as a real antigen in the body.
Human sperm was highly purified by the use of a discontinuous Percoll density gradient placed in an innercolumn of a centrifugation tube. Seminal plasma Contamination was only 0.0008 percent in the purified sperm. A new basic arginine ester hydrolyzing enzyme with a weak affinity for lima bean trypsin inhibitor (LBTI) Cellulofine column was found in the purified human sperm, and the characteristics of this enzyme were found to be different from those of human acrosin.
The urinary and biliary metabolites of a new antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1, 4-diazepin-1-yl)-1H-benzimidazole difumarate (KG-2413) in rats were identified by using a 14C-labelled drug and instrumental analyses, e.g., high performance liquid chromatography, gas chromatography (GC), 1H nuclear magnetic resonance, mass spectrometory (MS) and GC/MS. A slight amount of KG-2413 free base was detected only in the unconjugated fraction of urine. The main pathways of biotransformation of KG-2413 in rats were : (a) aromatic hydroxylation in the benzimidazole ring, (b) N-oxidation and N-demethylation in the 1, 4-diazepine ring, (c) α-carbon oxidation (lactam formation) in the 1, 4-diazepine ring (d) O-deethylation in the N-ethoxyethyl side chain. Regioselectivity was observed for aromatic hydroxylation, as only two of the four possible monohydroxylated metabolites could be detected. Furthermore, N-oxidation and lactam formation reactions were found to be regiospecific, that is, the former took place only at the position of 4-N atom and the latter at 5-C atom, respectively.
When 17β-hydroxyestra-1, 3, 5(10)-triene 17-sulfate was incubated with rat liver microsomes, the hydroxylations occurred predominantly at the position 2, followed by the 3. The hydroxylation at 4 was negligible. With proceeding the incubation time, two catechol metabolites hydroxylated at the positions 2, 3 and 3, 4 were produced. These catechols were confirmed as the second products derived from the above phenolic metabolites. Some kinetic parameters obtained by these hydroxylations showed that all the hydroxylases concerned are different enzymes.
Effects of aloctin A, glycoprotein isolated from leaves of Aloe arborescens MILL, on gastric secretion and on acute gastric lesions in rats were examined. Aloctin A given intravenously dose-dependently inhibited the volume of gastric juice, acid and pepsin output in pylorus-ligated rats. Aloctin A given intravenously significantly inhibited the development of Shay ulcers and indomethacin-induced gastric lesions in rats. It also inhibited water-immersion stress lesions induced in pylorus-ligated rats.
The grayanotoxin III (GTX III) was given intraperitoneally to rats at a dose of 0.8 or 2.8 mg/kg. To study the effects of GTX III on rats, biological tests in serum for functions of liver and kidney and their pathological observation were performed 1 h after the administration. Using analysis of variance, multiple comparison and correlation on biological parameters, activities of glutamic-pyruvic transaminase (GPT), guanase and leucine aminopeptidase and concentrations of total protein, albumin, creatinine, uric acid and K increased significantly. These parameters showed dose-effect relations with GTX III. Though GPT and free fatty acid increased significantly, dose-effect relations were not shown. The activity of choline esterase and the concentrations of bilirubin, urea-N, lipoperoxide, cholesterol, triglycerides, Na and Cl were not significantly different. Pathological changes were not observed in the liver and kidney of rats. These results show that GTX III may affect the functions of liver and kidney in rats.