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Biomedical subjects

M Tsuji

Publications and source records attributed to M Tsuji.

At least 487 records · Page 27Linked to original sources
PubMed1983

Hormonal regulation of activities of 4-ene-5 beta and 5 alpha-reductases and 17 beta-ol-dehydrogenase in immature golden hamster ovary.

Diethylstilbestrol (DES) pellets were implanted in female golden hamsters on day 22 after birth. Hamsters with or without the DES pellet were hypophysectomized on day 23. Starting from day 26, the hypophysectomized hamsters were injected daily with 2.3-40 micrograms NIH-LH-S19, 6 or 18 micrograms NIAMD-oFSH-13, 50 micrograms NIAMD-Rat-FSH-B-1, or saline for 3 days. Ovarian homogenates from these hamsters on day 29 were incubated with [14C]-4-androstene-3,17-dione and enzyme activity (nmol/g/h) was estimated. The 5 alpha- and 5 beta-reductase activities decreased significantly following hypophysectomy. In the hypophysectomized hamster ovary, a distinct response to LH but not to FSH or DES in the 5 alpha-reductase activity was found. On the other hand, the 17 beta-ol-dehydrogenase activity was stimulated by FSH but not by LH or DES. The 5 beta-reductase activity was stimulated by DES, FSH or 2.3 micrograms LH but not by 7-40 micrograms LH. In the DES-treated, hypophysectomized hamster ovary, LH and FSH stimulated the 5 alpha-reductase and 17 beta-ol-dehydrogenase activities, respectively, but FSH or LH treatment had no significant effect on the 5 beta-reductase activity. These results show that the 5 alpha-reductase activity is regulated by LH, while the 17 beta-ol-dehydrogenase activity is stimulated by FSH in immature golden hamster ovary. The 5 beta-reductase activity seems to be regulated predominantly by FSH but the effect of FSH is largely mediated by estrogen.

17-Hydroxysteroid Dehydrogenases↗
PubMed1983

Intratubular localization of 4-ene-5 beta-reductase and 17 beta-hydroxy-dehydrogenase in immature golden hamster testis.

We have reported [1,2] in immature golden hamster testis that 5 beta-reductase is localized in the seminiferous tubules, while 5a-reductase is present in the interstitial tissue and that the 17 beta-ol-dehydrogenase activity is found predominantly in the seminiferous tubules. In the present study, we show the intratubular localization of these enzymes. The left testis of golden hamster was irradiated with 2000R or 8000R of X-rays at 22 days of age. The hamsters were killed at 28 days of age. Homogenates of the left irradiated and right intact testes were incubated with [14C]-4-androstone-3,17-dione and NADPH, and enzyme activity was estimated. Both testes were also examined histologically. The X-irradiation of the testis resulted in an almost complete disappearance of germ cells with a significant decrease in testis weight, but the interstitial tissue and tubular nongerm cells including Sertoli cells remained almost unchanged. However, the activities of 5 beta-reductase and 17 beta-ol-dehydrogenase expressed as nmol formed/testis/h did not decrease at all. These results show that 5 beta-reductase is localized in the tubular nongerm cells including the Sertoli cells and 17 beta-ol-dehydrogenase is present in the tubular nongerm cells and interstitial tissue in immature golden hamster testis.

17-Hydroxysteroid Dehydrogenases↗
PubMed1983

The measurement of Ascaris suum protein by radioimmunoassay in sera from patients with helminthiasis and with gastrointestinal diseases.

In this study, we have developed a reliable radioimmunoassay (RIA) for Ascaris suum protein (Asp) and have measured the serum concentration of Asp in control subjects and in patients with helminthiasis and a variety of gastrointestinal diseases. The cross-reactivities of Asp antibody with other helminth worm antigens were also measured by RIA. Ascaris lumbricoides contained approximately the same amount of Asp antigenic substance as did Ascaris suum. Toxocara canis had a high concentration of a substance partially cross-reactive with Asp. Small amounts of substance cross-reacting with Asp were also exhibited by Anisakis larvae, Schistosoma japonicum and Taenia saginata. However, no cross-reactivities of Fasciola hepatica and Paragonimus westermani with Asp were observed in this study. Almost all the serum levels of Asp from normal control subjects were below the sensitivity of this RIA (10 ng/ml). High concentrations of Asp were observed in sera from patients with ascariasis (64.5 +/- 18.8 ng/ml: mean +/- S.E.), anisakiasis (75.2 +/- 28.0 ng/ml), toxocariasis (78.4 +/- 31.3 ng/ml) and schistosomiasis japonica (14.3 +/- 3.4 ng/ml). Asp levels in sera from patients with other helminthiasis were not significantly high. From these findings, it was suggested that RIA for Asp may not be specific for diagnosis of ascariasis, but might be a suitable screening method for patients with some kinds of helminthiasis. Interestingly, high concentrations of Asp were also observed in sera from patients with ulcerative colitis (24.8 +/- 2.5 ng/ml) and Crohn's disease (19.8 +/- 5.2 ng/ml), but Asp levels from 7 other gastrointestinal diseases seemed not to be significantly high. These findings remain unexplained but may derive from cross-reactivities between helminthic and gut mucosal antigens.

Animals↗
PubMed1983

Muscarinic cholinergic receptors of the convulsive strain (E1) mouse.

The biochemical characteristics of the muscarinic acetylcholine receptors were studied on the E1 strain mouse brain by the binding assay using [3H]1- quinuclidinyl benzylate. Scatchard analyses showed that the receptor density (Bmax) of the hippocampus significantly decreased by 26.4% and the affinity (Kd) increased by 18.8% in E1(+) compared to dd-Y. It is suggested that this hippocampal subsensitivity found in E1(+) mouse might be strain-specific, because repeated megimide convulsions failed to produce the same down regulation.

Animals↗
PubMed1983

Effect of multiplication-stimulating activity (MSA) on the cyclic AMP level and proteoglycan synthesis in cultured chondrocytes.

Multiplication-stimulating activity (MSA), a somatomedin purified from conditioned medium of Buffalo rat liver cells, had little effect on the intracellular level of cyclic AMP when it markedly enhanced the synthesis of sulphated glycosaminoglycans in rabbit chondrocytes in culture. In addition, MSA did not inhibit prostaglandin E1- or parathyroid hormone-induced accumulation of cyclic AMP in the chondrocytes. On the contrary, MSA slightly decreased stimulation of cyclic AMP accumulation by prostaglandin in human fibroblasts. Dibutyryl cyclic AMP and MSA increased the incorporation of [35S]sulphate and [3H]serine into proteoglycans synthesized by rabbit chondrocytes, and their effects were additive. These findings suggest that somatomedin and dibutyryl cyclic AMP enhance sulphate proteoglycan synthesis through different mechanisms. The lack of inhibitory effect of MSA on cyclic AMP accumulation may be favourable for producing additive effects with cyclic AMP on proteoglycan synthesis and DNA synthesis in chondrocytes.

Alprostadil↗
PubMed1983

Effect of pharmacological doses of estrogen on ovary-independent rat mammary carcinoma containing estrogen and progesterone receptors.

Mammary carcinoma induced in male Sprague-Dawley rats by multiple intragastric intubations of 7,12-dimethylbenz-(a)anthracene showed ovary-independent growth but contained estrogen receptors (ER) and progesterone receptors (Yoshida, Yoshida. Fukunishi, Sato, Okamoto, and Matsumoto, Cancer Res., 42: 2434-2439, 1982). Transplantable carcinoma (MT6) was obtained from dimethylbenz(a)anthracene-induced mammary carcinoma and then maintained in male rats. MT6 tumors with ER grew equally well in males, females, gonadectomized males, males given injections of bromocryptine (1 mg/day) or lisuride hydrogen maleate (50 micrograms/day), and gonadectomized males receiving smaller doses of 17 beta-estradiol (1 to 100 micrograms/2 days). However, the growth of MT6 was inhibited markedly by injection of a very large amount of 17 beta-estradiol (1 mg/2 days). Although transplanted MT6 tumors were ductal carcinoma with cribriform pattern with ER, tumors recurring after injection with 1 mg 17 beta-estradiol were found to be spindle cell carcinoma without ER, which could grow equally well in recipients treated with or without 1 mg 17 beta-estradiol. These observations suggest that the growth of ovary-independent MT6 tumors with ER and progesterone receptors is inhibited only by pharmacological doses of estrogens and that the loss of growth-inhibiting effect of pharmacological doses of estrogen of MT6 tumors occurs during high-dose estrogen treatment.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1982

5 beta- and 5 alpha-reductases for 4-ene-3-ketosteroids in golden hamster ovaries at different stages of development.

Ovarian homogenates from 10-, 23- 128- and 60-day-old golden hamsters were incubated with [14C]-4-androstene-3,17-dione or [7-3H]-progesterone in the presence of NADPH and enzyme activities and metabolism of progesterone were estimated. A rapid increase in uterine weight was found around 28 days of age. The activity of 5 alpha-reductase was very high in the ovaries of 23-day-old hamsters (647 +/- 117 (SD) nmol/g tissue/h), high in those of 28-day-old hamsters (135 +/- 4) and low in those of 10- and 60-day-old animals (20 +/- 16, 39 +/- 11). However, the activity of 5 beta-reductase was high in all ovaries of golden hamsters at different stages of development (84-132 nmol/g tissue/h). The major C-21-17-hydroxysteroids and C19-steroids formed from progesterone by the ovaries of 23-day-old hamsters were 5 alpha-steroids such as 3 alpha, 17-dihydroxy-5 alpha-pregnan-20-one and androsterone, whereas those by the ovaries of 28- and 60-day-old hamsters were 4-ene-3-ketosteroids and 5 beta- and 5 alpha-steroids such as 17-hydroxy-4-pregnene-3,20-dione. 3 alpha, 17-dihydroxy-5 alpha- and 5 beta-pregnan-20-one, 4-androstene-3,17-dione, testosterone and androsterone. The formation of oestradiol-17 beta and oestrone from progesterone was found only in the ovaries of 38- and 60-day-old hamsters. These results show that similarly high levels of 5 beta-reductase are present in all ovaries from suckling, immature and adult golden hamsters and that high levels of 5 alpha-reductase are formed only in ovaries from immature hamsters, especially those with small uterus. The active 5 alpha-reduction of 4-ene-3-ketosteroids may be responsible for the decrease in the formation of oestrogens in immature hamster ovaries.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1982

Effect of bone-derived growth factor on DNA, RNA, and proteoglycan synthesis in cultures of rabbit costal chondrocytes.

Calvariae and chondrocytes in culture have been reported to release growth factors which stimulate bone and cartilage growth respectively. In the present studies, we examined the effects of bone-derived growth factor (BDGF) on DNA, RNA and proteoglycan synthesis in cultured rabbit chondrocytes. Two partially purified fractions of BDGF were tested, one with an approximate molecular weight (MW) of 20-30,000 and with greater activity on calvarial DNA labeling (BDGF I) and another with an approximate MW 6-13,000 and greater activity on bone collagen labeling (BDGF II). Both fractions had a similar effect and increased the incorporation of -3H-uridine into acid insoluble residues in chondrocytes and the incorporation of 35SO4(2-), 3H-glucosamine and 3H-serine into proteoglycans. However, BDGF II had a greater stimulatory effect on the incorporation of 3H-thymidine than BDGF I. These findings suggest that factor(s) released by bone cells are capable of stimulating cartilage metabolism and growth.

Animals↗