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Biomedical subjects

K Katayama

Publications and source records attributed to K Katayama.

At least 541 records · Page 30Linked to original sources
PubMed1977

Effect of follicle-stimulating hormone (FSH) and estrogen on follicle growth in rats.

The effect of follicle-stimulating hormone (FSH) and diethylstilbestrol (DES) on ovarian follicle growth was studied in hypophysectomized rats, using histologic, autoradiographic and histochemical techniques. The administration of FSH to immature hypophysectomized rats stimulated the follicle growth with thickening of the theca layer and repair of "deficiency cells". Although DES given to hypophysectomized rats also stimulated the follicle growth, the theca layer was relatively thin compared with that in FSH-treated rats. In order to detect cell division in a growing follicle, the number of labelled granulosa cells with tritiated thymidine as a proportion of the granulosa cells in a growing follicle were counted and the labelling indices of the granulosa cells were calculated. The labelling indices increased by the administration of FSH (p less than 0.05) or DES (p less than 0.05). The uptake of tritiated thymidine and leucine by the theca cells was enhanced only by FSH and was not stimulated by DES. The administration of FSH resulted in an increase of the histochemically demonstrable enzyme activity such as delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) or alkaline phosphatase in the theca cells. In contrast, the administration of DES did not stimulate the enzyme activity of the theca cells. Furthermore, FSH stimulated a release of estradiol and estriol from the ovary of hypophysectomized rat, whereas DES did not. Although ovarian follicle growth was stimulated by both FSH and DES, the effect of the two hormones on the theca cells was quite different and the secretion of estrogen was stimulated by FSH. The results suggest that FSH induced follicle growth of the ovary might be mediated by estrogen produced by the theca cells.

Alkaline Phosphatase↗
PubMed1977

Studies on biotransformation of lysozyme. III. Comparative studies on biotransformation of exogenous and endogenous lysozyme in rats.

Exogenous hen lysozyme or endogenous rat lysozyme labeled with 131I was intravenously injected to rats with the same dosage, respectively, and the uptake and degradation of injected 131I-labeled rat lysozyme in liver and kidney were studied in comparison with those of 131I-labeled hen lysozyme. 1. Although the serum levels of both enzymes injected were almost indentical during the first 6 h, the liver uptake of 131I-labeled hen lysozyme was 2.2-fold more than that of 131I-labeled rat lysozyme at the peak time of 5 min after injection. The uptake and clearance of 131I-labeled rat lysozyme in the kidney were exclusively slow as compared with those of 131I-labeled hen lysozyme. 2. The intracellular distribution in the liver and kidney were examined by the differential centrifugation after injection of each lysozyme. The protein-bound radioactivity of each subcellular fraction was found to be the highest in the 12 000 X g (10 min) fraction in the liver and the 19 600 X g (20 min) fraction in the kidney. The relative specific activity of 12 000 X g fraction of the liver after injection increased with the time lapse. On the other hand, the relative specific activity of 105 000 X g (1 h) fraction of the liver attained a maximum within 5 min after injection and thereafter decreased. It was assumed that the mechanism of the uptake of injected 131I-labeled rat lysozyme in the liver and kidney was similar to that of 131I-labeled hen lysozyme. 3. The degradation of exogenous or endogenous lysozyme in subcellular particles was examined. From the effect of pH, activator and inhibitor on the degradation, the proteolytic enzyme to degrade the injected 131I-labeled hen lysozyme was indicated to be mainly cathepsin BL, with the optimal pH of about 5.0, and the injected 131I-labeled rate lysozyme was mainly degraded by cathepsin D, with the optimal pH of about 3.5 The in vitro degradation of exogenous and endogenous lysozymes showed a tendency similar to the in vivo clearance from the liver and kidney.

Animals↗
PubMed1977

Binding of LH and FSH to porcine granulosa cells during follicular maturation.

The uptake of 125I-labelled LH by equal numbers of granulosa cells from small, medium or large follicles was greater by cells from large follicles. In contrast, granulosa cells obtained from small follicles bound much more 125I-labelled FSH per cell than did cells obtained from medium and large follicles. Competition studies with unlabelled hormones indicated that porcine granulosa cells have specific receptors for LH and FSH. The addition of diethylstilboestrol enhanced the binding of 125I-labelled LH and inhibited the binding of 125I-labelled FSH to granulosa cells harvested from small and medium-sized follicles, but had no effect on those from large follicles.

Animals↗
PubMed1976

Metabolism of chenodeoxycholic acid in hamsters.

The study on the metabolism after oral administration of chenodeoxycholic acid-24-14C was performed by analysis of radioactivity that had appeared in bile and feces of male hamsters. The radioactive bile acids were analyzed by thin layer chromatography and identified by the isotope dilution method. In the bile of the hamsters with bile fistula, radioactivity was originated from unchanged chenodeoxycholic acid for the most part, and 7-ketolithocholic acid, lithocholic acid, and beta-muricholic acid for the remainder. In the feces lithocholic acid, dehydrolithocholic acid, isolithocholic acid, and unchanged form were identified. After the multiple dosing of chenodeoxycholic acid-24-14C for 6 days, beta-muricholic acid was also identified in the feces.

Administration, Oral↗