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Biomedical subjects

R Nakano

Publications and source records attributed to R Nakano.

At least 19 recordsLinked to original sources
PubMed1992

Gonadotropin receptors in human ovarian follicles and corpora lutea throughout the menstrual cycle.

To study changes in the binding of gonadotropins to human follicles and corpora lutea, we have examined the binding of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the human ovary throughout the menstrual cycle, by both quantitative binding assays and surface binding autoradiography. The specific high-affinity low-capacity receptors for hLH were demonstrated in both human follicles and corpora lutea. Binding of 125I-hFSH was identified in the granulosa cells, but not in the thecal cells of the preantral and antral follicles at various stages of follicular development. The binding of 125I-hLH to the thecal cells increased during follicular development, and a dramatic increase was preferentially observed in the granulosa cells of the preovulatory follicles. In the corpora lutea, the binding of 125I-hLH increased from the early luteal phase to the midluteal phase and decreased towards the late luteal phase. The results of the present study suggest that changes in the binding of gonadotropins in the ovarian target cells during the menstrual cycle might play an important role in the regulation of follicular and luteal function.

Autoradiography↗
PubMed1992

Follicle-stimulating hormone induces functional receptors for basic fibroblast growth factor in rat granulosa cells.

In the present study we examined the existence of receptors for basic fibroblast growth factor (bFGF) and its regulation in rat granulosa cells. The binding of labeled bFGF to rat granulosa cells was dose-dependently displaced by unlabeled bFGF, but not other growth factors. FSH induced a dose-dependent increase in specific binding for bFGF to cultured rat granulosa cells. FSH treatment did not change the binding affinity (Kd, 2.8-3.0 x 10(-10) M) of the bFGF receptor, but increased the total number of bFGF-binding sites, whereas treatment with several steroid hormones had no effect on the specific binding of bFGF. Since cycloheximide, a protein synthesis inhibitor, inhibited the increase in bFGF binding induced by FSH, it is suggested that protein synthesis might be involved in the FSH stimulation of bFGF receptor induction. Furthermore, bFGF stimulated tissue plasminogen activator activity in a dose-dependent manner, and FSH-primed granulosa cells were more responsive to bFGF action, with a decrease in the ED50 from 5.0 to 1.5 ng/ml. The antibody against human bFGF neutralized the stimulatory effect of bFGF on tissue plasminogen activator secretion. The present study suggests that FSH induces functional receptors for bFGF in granulosa cells and that bFGF may play a role in the process of differentiation under the influence of FSH.

Animals↗
PubMed1990

High cell density suspension culture of mammalian anchorage independent cells: oxygen transfer by gas sparging and defoaming with a hydrophobic net.

Gas sparging directly into the culture-broth is not done in cell culture, except when the gas flow rate is very small, because much foaming occurs. During screening of defoaming methods, foam was observed to be broken up effectively when it made contact with a net fabricated from hydrophobic materials. Providing a highly efficient oxygen supply to suspension culture was tried using the new defoaming method. In a 5 l reactor equipped with the foam-eliminating net fabricated with polysiloxane, oxygen was transferred at 21 mmole/l.h equivalent to a consumption rate of 1 X 10(8) cells/ml, even at a low oxygen gas flow rate of 0.1 cm/s corresponding to a fourth of the gas flow rate when foam leaked through the net. Perfusion culture of rat ascites hepatoma cell JTC-1 was successfully carried out in the 5 l scale culture system with the net and a hydrophobic membrane for cell filtration. The viable cell concentration reached 2.7 X 10(7) cells/ml after twenty-seven days, in spite of the nutrient-deficient condition of the lower medium exchange rate, that is, a working volume a day, and viability was maintained at more than 90%. In a 1.21 scale culture of mouse-mouse hybridoma cell STK-1, viable cell concentration reached 4 X 10(7) cells/ml. These results showed that oxygen transfer by gas sparging with defoaming was useful for high density suspension culture. A foam-breaking mechanism was proposed.

Animals↗
PubMed1979

Diagnostic evaluation of progesterone. Challenge test in amenorrheic patients.

Forty-one amenorrheic patients were grouped on the basis of presence or absence of withdrawal uterine bleeding following the intramuscular administration of progesterone. Ovarian volume, ovarian morphology with particular reference to presence or absence of follicles and state of follicular development, and steroidogenic function were investigated in each group. Most of amenorrheic patients with progesterone-induced uterine bleeding had relatively large ovaries with follicles of high developmental stage (tertiary-Graafian follicle) and responded to exogenously administered HMG and HCG with a rise in the 24-hour urinary excretion of total estrogens. In contrast, most of amenorrheic patients without progesterone-induced uterine bleeding had relatively small ovaries without follicles or with follicles of low developmental stage (primordial-secondary follicle) and did not respond to exogenous HMG and HCG. The results of the present study suggest that presence or absence of progesterone-induced uterine bleeding is closely correlated with the volume, morphology and steroidogenic function of the ovary in amenornorrheic patients. Thus, pathologic amenorrhea could be divided into two groups by utilizing the progesterone challenge test and this clinical categorization might be useful for the diagnosis and treatment of amenorrheic patients.

3-Hydroxysteroid Dehydrogenases↗
PubMed1978

Ovarian follicular apparatus and hormonal parameters in patients with primary and secondary amenorrhea.

Correlation between ovarian follicular apparatus and hormonal parameters such as serum gonadotropin and urinary estrogen levels was investigated in patients with primary and secondary amenorrhea. Serum gonadotropin levels were elevated in amenorrheic patients without ovarian follicles or with follicles of low developmental stage and pituitary responsiveness to LH-RH in these patients were marked compared with patients with follicles of high developmental stage or normal ovulating women in the follicular phase of the menstrual cycle. The 24-hour urinary excretion of total estrogens was low in patients without follicles or with follicles of low developmental stage and ovarian responsiveness to exogenous gonadotropins was quite low in comparison with patients with highly developed follicles or normal control subjects. Thus, serum gonadotropin and urinary estrogen measurements and LH-RH and gonadotropin loading tests are diagnostic of the presence or absence and the state of development of ovarian follicles in the diagnosis and treatment of primary and secondary amenorrhea.

Adult↗
PubMed1978

Chromosome studies of embryos from induced abortions in pregnant women age 35 and over.

Chromosome studies of embryos were done in abortions induced at the early stage of pregnancy in women 35 years of age and older who had no signs of threatened or spontaneous abortions and were considered to have oocytes of an advanced age. Karyotypes were successfully determined in 256 cases and the results were as follows: a) 2 of 123 cases in 35- to 39-year-old women showed an incidence of chromosomal anomalies as high as 1.6%; 7 of 117 cases in 40- to 44-year-old mothers an incidence of 6.0%; and 4 of 16 mothers in the 45- to 49-year-old age group an incidence of 25.0%; b) all chromosomal anomalies were trisomies, mainly trisomy 21 and 18. These results suggest that the incidence of chromosomal anomalies increases in older pregnant women, especially in premenopausal pregnancies, and that non-disjunction may occur during meiosis.

Abortion, Induced↗
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

A schematic approach to the work-up of amenorrhea.

Amenorrhea is a symptom having many possible causes. Since amenorrhea can result from disturbed function anywhere in the hypothalamic-pituitary-ovarian-uterine axis, a specific etiologic diagnosis must be made if treatment is to be effective. For this purpose, a diagnostic scheme for the differential diagnosis of the etiology of primary and secondary amenorrhea is proposed. This scheme includes a progestin test, a cyclic estrogen and progestin test, a luteinizing hormone-releasing hormone (LH-RH) loading test, and a gonadotropin (human menopausal gonadotropin and human chorionic gonadotropin) loading test. A specific pattern of responses to LH-RH and gonadotropins exists in patients with hypothalamic, pituitary, and ovarian amenorrheas, respectively, and the character of the response may facilitate the etiologic diagnosis of amenorrhea. The clinical usefulness and/or value of the scheme in the diagnosis and treatment of amenorrheas is discussed.

Adult↗
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↗
PubMed1975

Ovarian response to exogenously administered human gonadotropins during the postpartum period.

Eighteen normal puerperal women received a combined administration of human menopausal gonadotropin (HMG) and human chorionic gonadotropin (HCG) and the ovarian response to these human gonadotropins was evaluated by the daily estimation of the 24 hour urinary excretion of total estrogens. Fourteen of the 18 subjects studied were responsive to the exogenously administered gonadotropins with a rise in the urinary estrogen excretion. Moreover, plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels during the postpartum period were low compared to normal cycle gonadotropin levels. Thus, it might be concluded that puerperal anovulation and amenorrhea during lactation might be due to hypophyseal gonadotropic dysfunction rather than to ovarian refractoriness.

Amenorrhea↗