To elucidate the mechanism of proinsulin induction by glucose, we determined the amount of proinsulin messenger ribonucleic acid (mRNA), the subcellular distribution of proinsulin mRNA and the transcriptional activity of proinsulin gene in isolated pancreatic islets of rat. From these results, we concluded that the stimulation of proinsulin synthesis was mainly regulated at the translational level. To elucidate the primary structure of vasoactive intestinal peptide (VIP) precursor, we determined the nucleotide sequence of VIP complementary deoxyribonucleic acid (cDNA). The entire amino acid sequence of the VIP precursor indicates that the precursor protein contains not only VIP but also PHI-like peptide. We also found that the induction of pro-VIP synthesis was achieved by enhancing the transcription rate of VIP gene. We also isolated fibroblast growth factor (FGF) receptor cDNA. The nucleotide sequence of FGF receptor cDNA indicates that the receptor is a transmembrane protein that contains extracellular immunoglobulin-like domains and an intracellular tyrosine kinase domain. We also found that the receptor had two isoforms of the extracellular domains and that the expression of the isoforms was regulated tissue-specifically.
The use of biocatalysts for the preparation of new chiral synthons has provided a novel synthetic route to the useful natural products. A method for the preparation of chiral carbocyclic alcohols has been also developed by utilizing the Pseudomonas fluorescens lipase (PFL)-catalyzed enantioselective hydrolysis. The above-mentioned alcohols have been found to be effective as chiral auxiliaries for asymmetric reactions.
The therapeutic use of prostaglandins (PGs) which contain various biological activities and are unstable was successfully achieved. PGs were produced in a large scale according to the Corey method and could be stabilized by the formation of a clathrate compound with cyclodextrin, which enabled the production of marketable form of highly pure PGs. Diligence in the development of native PGs and their structural analogs for human therapy resulted in the following six drugs now being on the market in Japan : PGF2α as the first drug of PGs in the world which induces labor ; PGE2 as an orally active labor inducing drug ; PGE1 for the treatment of peripheral vascular diseases ; gemeprost for therapeutic abortion in the middleterm ; ornoprostil, as an oral anti-ulcer agent ; limaprost for the treatment of peripheral vascular diseases as an oral agent.
Fifteen kinds of uracil derivatives, which were substituted with functional groups such as benzyl (Bn), methoxymethyl (MOM), n-propyl (Pr) or allyl (A) group at the N1 and/or N8 position of uracil, were synthesized. Sedative-hypnotic activity, pentobarbital (PB)-induced sleep prolongation and acute toxicity as indices of their pharmacological activities were evaluated using mice. Spontaneous activities of mice treated with N1-benzyluracil (N1-BnU, 7), N8-benzyluracil (N8-BnU, 8), N1, N8-dibenzyluracil (DBnU, 9), N1-benzyl-N8-allyluracil (BnAU, 14) and N1-allyl-N8-benzyluracil (ABnU, 15) were measured. Ten kinds of uracil derivatives showed hypnotic activity. ED50's values of ABnU (15) and N1-propyl-N8-benzyluracil (PrBnU, 13) were 155 and 172 mg/kg, i.p., respectively. Those effects were more potent than that of barbital (179 mg/kg, i.p.). Ten kinds of uracil derivatives tested significantly prolonged the PB-induced sleeping time. N8-BnU (8) increased the spontaneous activity of mice at a dose of 80 mg/kg, i.p., while ABnU (15) depressed the spontaneous activity at a dose of 160 mg/kg, i.p. The other compounds did not show any significant effect on the spontaneous activity of mice. LD50's values of ABnU (15), PrBnU (13) and N1-methoxymethyl-N8-benzyluracil (MOMBnU, 11) were 199, 229 and 363mg/kg, i.p., respectively. LD50's values of the other derivatives were more than 480 mg/kg, i.p. These results indicate that the benzyl group at the N8 position of uracil is important for exhibiting sedative-hypnotic activity of uracil derivatives, and that ABnU (15) has the most potent central depressant activity among the uracil derivatives tested.
The piperazine N-alkylcarboxylic acids of 2-chlorodibenz[b, f] [1, 4] oxazepine (3a), 2-chlorodibenzo[b, f] [1, 4] thiazerine (3b), and dipenz[b, e]azepine (3c) from the corresponding piperazines (1a-c, R1=H) were synthesized via the piperazine N-alkylcarboxylates (2a-c). The pharmacolosical activities of the piperazine N-alkylcarboxylic acids (3a-c) were evaluated. Compared with the parent compounds (1a-c), 3a-c (n=1-5) showed weak inhibitory activities on the uptake of noradrenaline and 5-hydroxytryptamine (5-HT) into hypothalamus vesicles and moderate antagonistic actions to 5-HT2 and H1 in several tissues.
The antitumor activity of kefir (YK-1), a fermented milk product in Caucasus, was investigated. YK-1 at oral doses of 100 or 500 mg/kg inhibited the proliferation of solid tumor of Ehrlich ascites carcinoma transplanted subcutaneously in mice. YK-1 did not show an inhibitory effect on the ear swelling induced contact dermatitis caused by picryl chloride (PC-CD). However, YK-1 inhibited the immunosuppression in Ehrlich carcinoma-bearing mice and with the freezed and dried ascites of the tumor-bearing mice containing immunosuppressive substances (EC-sup) in PC-CD-induced mice. And also, YK-1 activated the immunosuppressive activity of spleen cells of mouse treated with EC-sup. These results suggest that YK-1 may have antitumor activity against Ehrlich carcinoma and activate the immunosuppression with it.
Glycyrrhizinates such as monoammonium and dipotassium glycyrrhizinates which are extracted from licorice, convertea to easily water-soluble salts and refined have been formulated in many quasi-drug products as an anti-inflammatory agent. A quantitative analysis of glycyrrhizinates in quasi-drug products has usually and successfully been carried out by high performance liquid chromatography (HPLC). However, a slightly higher value than the actual content has sometimes been observed in daily analysis. As the result of our various studies to investigate these phenomena, we finally found that a minor constituent in commercial glycyrrhizinates, which was identified as monomethyl glycyrrhizinate, was hydrolyzed after they were formulated in quasi-drug products and converted to glycyrrhizin which in turn was determined by HPLC as a higher value.