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Biomedical subjects

K Obara

Publications and source records attributed to K Obara.

At least 199 records · Page 11Linked to original sources
PubMed1977

Separation of non-melatonin antiovulatory substances from bovine pineal powder by ultrafiltration.

An attempt was made to partially separate substances which inhibit the induced ovulation by PMS and hCG in immature mice from the sodium borate buffer extract of bovine pineal powder by means of ultramembrane filtration. The antiovulatory activities were concentrated in fractions which possess materials of a molecular weight greater than 10,000 and also in fractions containing substances of a molecular weight less than 1000. The proteinaceous large inhibitor was thermostable while the small inhibitor, which is different from melatonin or arginine vasotocin, was inactivated by heating.

Animals↗
PubMed1977

Further studies on gonadotropin-inhibiting substances excreted in human urine.

Partial separtion of human urinary substances which have properties to suppress the ovulation induced by PMS and HCG in mice was attempted by gel filtration on Sephadex G-100 and ultrafiltration using the Amicon Diaflo membranes UM-2 and UM-10. In addition to a thermostable inhibitor which has a molecular weight more than 10,000, the presence of heat-labile inhibitor with a molecular weight less than 1,000 was newly demonstrated.

Animals↗
PubMed1977

Catecholamine metabolism in the patients with rheumatoid arthritis.

The amount of urinary catecholamine of healthy subjects and patients with rheumatoid arthritis, particularly before and after synovectomy, was studied. (1) The urinary catecholamine of patients with rheumatoid arthritis showed a lower value than that of healthy subjects. The greater the amount of intraarticularly injected steroids was and the more severe the stage and class of rheumatoid arthritis were, the lower the level of adrenaline was and the more reduced the activity of phenylethanolamine-N-methyltransferase was. (2) The level of urinary noradrenaline in patients with rheumatoid arthritis was lower than that of healthy subjects, but there was no relationship between the level of noradrenaline and the amount of intraarticularly injected steroids. Considering that noradrenaline tended to approach to the normal level as the stage of class of rheumatoid arthritis was more severe, the level of urinary noradrenaline in patients with rheumatoid arthritis seems to reflect the existence of a certain compensatory system in the enzyme system of catecholamine metabolism rather than the influence of the adrenal cortex system. (3) The urinary catecholamine was decreased after synovectomy; especially, noradrenaline level was remarkably decreased. These results suggest that catecholamine plays an important role in the appearance of pain or other clinical signs in rheumatoid arthritis.

Adult↗
PubMed1977

Effect of riboflavin deficiency on the 32P turnover in the macromolecular phosphate compounds of the rat lens.

In order to clarify the role of riboflavin in phosphorylation in the lens, the authors have attempted to investigate the 32P turnover in the macromolecule fraction in the lens supernatant from riboflavin deficient rats. 32P turnover in the macromolecular phosphate compounds was reduced remarkably. The macromolecular phosphate compounds in the lens supernatant which was separated by Sephadex G-50 was identified as RNA. These findings reveal that there are close relationships between reduced RNA turnover in the lens and riboflavin deficiency. This concept may contribute greatly to clarifying the pathogenesis of ariboflavinosis in general.

Animals↗
PubMed1977

The effects of actinomycin D and puromycin on the induction of the cytosol enzymes involved in the androgen metabolism by testosterone in female rat liver.

Induction of the cytosol enzymes involved in the androgen metabolism in the female rat liver by testosterone was studied. The treatment by testosterone propionate increased the production of 5beta-androstane-3alpha,17beta-diol in the 105.000xg supernatant when 4-14C-testosterone was used as a substrate. The conversion of 4-14C-androstenedione to labelled testosterone was increased by the injection of testosterone propionate into female rats. Actinomycin D or puromycin which was administered for four days with daily subcutaneous injections of testosterone propionate prevented the increase of these enzymes by testosterone propionate. Actinomycin D given once with the final injection of testosterone propionate blocked the induction of cytosol 17beta-hydroxysteroid dehydrogenase by the treatment of testosterone propionate, whereas puromycin given in the same manner as actinomycin D had no such a blocking effect on the enzyme. Both of these antibiotics given once with the final injection of testosterone propionate showed no preventing effects on the induction of cytosol delta4-5beta-reductase by testosterone propionate.

Androgens↗
PubMed1976

Effect of malnutrition on cortisol-binding protein in the lens of cynomolgus monkeys.

A cortisol-binding protein exists in the lens of cynomolgus monkeys as in other species. The cortisol-binding capacity decreased markedly with a diet either moderately or severely depleted of protein, even if the diet was later changed to a normal diet during infancy. This suggests that malnutrition may cause insufficient synthesis of the important factors controlling the inactivation of steroid hormone in the lens.

Animals↗
PubMed1976

Some biochemical changes in lenses of riboflavin deficient rats.

In order to better understand the role of riboflavin in the lens, we investigated the lenses of rats fed on a riboflavin deficient diet for 7 weeks to determine changes in the inactivation of cortisol, the glucose-6-phosphate dehydrogenase (G-6-PD) activity and the histidine or 5-hydroxytryptophan decarboxylase activity. The cortisol-binding capacity and G-6-PD activity in the lenses of rats fed on a riboflavin deficient diet were found to be decreased as compared with a control. Histidine decarboxylase activity was found twice as high in the riboflavin deficient rats as in the normal lenses however, 5-hydroxytryptophan decarboxylase was somewhat decreased. These findings show that catabolical changes in the metabolism of rat lenses are induced comprehensively by feeding on a riboflavin deficient diet in the same manner as changes are seen in the cataractous lens.

5-Hydroxytryptophan↗
PubMed1975

Lowering effect of carbon tetrachloride on microsomal cytochrome P-450 of rat liver.

The lowering effect of carbon tetrachloride (CCl4) on the amount of hepatic microsomal cytochrome P-450 of male rats was studied in vitro. It was found that CCl4 added directly into the media containing microsomal supensions decreased the amount of cytochrome P-450 detectable by difference spectra at zero time of incubation. The incubation of the media with CCl4 at 37 degrees in an open system or in a closed system did not decrease the content of cytochrome P-450. As cytochrome P-420 was not detected in the addition of CCl4 lower than 10 mul, it was postulated that the decrease in the content of cytochrome P-450 was not due to its conversion to cytochrome P-420. The activity of NADPH-cytochrome c reductase was not affected by CCl4. The results indicate that the decrease of the amount of detectable cytochrome P-450 by CCl4 is due to the destruction of cytochrome P-450 and the binding of cytochrome P-450 with CCl4in a lower concentration of CCl4 and in addition it is due to the conversion of cytochrome P-420 from cytochrome P-450 in a higher concentration of CCl4.

Animals↗
PubMed1975

Inhibition of ovulation induced with PMS and HCG by a melatonin-free extract of bovine pineal powder.

Using borate buffer a substance that suppresses the ovulation induced with PMS and HCG in immature mice was obtained from acetone-defatted bovine pineal powder by an extraction method similar to that used for an extraction of a gonadotropin-inhibiting substance in urine. This gonadotropin inhibitor in the pineal powder differs from melatonin or arginine vasotocin and seems to be different from the water soluble antigonadotropic substance which has been isolated from the bovine and ovine pineal. Partial purification of the gonadotropin inhibitor was accomplished by a Sephadex G-100 column.

Animals↗
PubMed1975

Tryptophan metabolism in the joint diseases.

Tryptophan metabolites through kynurenine pathway and 5-hydroxytryptophan pathway in the synovial fluid, blood and urine of patients with rheumatoid arthritis and those with osteoarthritis were investigated in order to know the specificity of the tryptophan metabolism, especially the role of serotonin in the joint diseases. A metabolic map of tryptophan in the synovial fluid was also made. It was found that tryptophan in rheumatoid arthritis was metabolized mainly to anthranilic acid through kynurenine in the kynurenine pathway, whereas in osteoarthritis the pathway of kynurenic acid and nicotinic acid was characteristic. Otherwise in 5-hydroxytryptophan pathway there were no significant differences in the levels of 5-hydroxytryptamine and 5-hydroxyindole acetic acid in the synovial fluid between rheumatoid arthritis and osteoarthritis but the activity of monoamine oxidase in the synovial fluid was higher in osteoarthritis than in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1975

Synergistic effects of fad and acth on the 32-p turnover in the adrenal of rats treated with a one shot administration of dexamethasone phosphate.

The effects of Flavin Adenine Dinucleotide (FAD) and of vitamin A for two days to 25 days old rats has been studied on liver of rats treated with a one shot administration of dexamethasone phosphate were investigated. Efforts were made to determine whether or not ACTH participates in the action of FAD which affects adrenal atrophy induced by steroid hormone administration. The large decrease in adrenals 32-P turnover in rat treated with a one shot administration of dexamethasone phosphate was reduced by intraperitoneal administration of FAD or ACTH alone. This tendency of reduced loss was further promoted by an administration of ACTH simultaneously with the FAD. These results suggest the presence of a new physiological role for FAD i.e. FAD is able to potentiate the action of ACTH. The role was discussed of a possible synergism between FAD and ACTH with regard to their action on the induction of adrenal atrophy by steroid administration.

Adrenal Glands↗