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Biomedical subjects

H Minaguchi

Publications and source records attributed to H Minaguchi.

At least 109 records · Page 6Linked to original sources
PubMed1984

Increases in ovarian GnRH receptors by following GnRH treatment.

Using a gonadotropin-releasing hormone (GnRH) analog, [D-Ser (tBu6)] des-Gly10-GnRH-N-ethlamide (GnRHa) as a ligand the binding capacity of the rat ovary to GnRH during sexual maturation and the mechanism regulating GnRH binding capacity were examined. Specific high affinity binding sites for GnRH were observed in the ovary and the Kd values for the granulosa cells and the residual tissue were similar to those of whole ovary. During sexual maturation, the GnRH binding capacity of the ovary rose from 7 days of age to a peak of 28 days and declined during the prepubertal period. The treatment with PMSG decreased GnRH binding capacity in the residual tissue as well as in the whole ovary but did not change the binding capacity in the granulosa cells in diethylstilbestrol (DES) primed hypophysectomized rats. Repeated injections of GnRH caused a significant increase in the number of GnRH receptors of the ovary in PMSG treated DES primed hypophysectomized rats but not in the saline treated rat. The granulosa cells exhibited increases in GnRH binding capacity following repeated administrations of GnRH more than the residual tissue did. In GnRH treated DES primed hypophysectomized rats, increasing doses of PMSG increased the binding capacity in the granulosa cells but decreased the binding capacity in the residual tissue. From these findings, GnRH in combination with PMSG seems to have stimulatory effects on GnRH binding capacity and to increase the sensitivity to GnRH in the granulosa cells.

Animals↗
PubMed1983

[Fundamental and clinical studies of T-1982 (cefbuperazone) in the field of obstetrics and gynecology].

Fundamental and clinical studies on T-1982 (cefbuperazone), a new cephamycin antibiotic, in the field of obstetrics and gynecology were carried out, and the following results were obtained. The levels of T-1982 transferred to uterine artery, elbow vein and uterus were determined after intravenous drip infusion of 1.0 g for 1 or 2 hours. No difference of concentration between uterine artery and elbow vein was observed from 45 minutes to 5 hours after the end of administration. The concentration of T-1982 in uterine artery ranged from 9.8 to 48 micrograms/ml after drug administration, and decreased slowly, but remained at about 10 micrograms/ml even 5 hours after the end of administration. Endometrium exhibited comparatively higher concentration of T-1982, but the difference of concentration was not observed among the other uterine tissues. T-1982 concentration ratios of various uterine tissues to elbow vein blood ranged from 172 to 10.2%, and mean ratio was 34.7%. Also, T-1982 concentration of more than 3 micrograms/g in each tissue was maintained for 2 hours after the end of administration. Clinical results on abscess of Bartholin's gland (1) and adnexitis (1) were good, although bacteria were not detected. No side effects caused by the drug were observed. These results indicate the usefulness of T-1982 in the treatment of infections in obstetrics and gynecology.

Adult↗
PubMed1982

[Endocrinological analysis of hypothalamic primary amenorrhea (author's transl)].

Primary amenorrhea, in which serum concentrations of gonadotropins are low or normal, has been considered to be relatively rare. Recent analysis in our outpatient clinic revealed that the incidence of hypothalamic primary amenorrhea is higher than previously appreciated, comprising 26.7% of the total primary amenorrheas. Endocrinological functions of the hypothalamo-hypophyseo-ovarian axis in these patients were therefore investigated. Studies on gonadotropin secretion indicated that a disturbance in LH-RH secretion and a lack of estrogen positive feedback were principle features of this disease. In addition to the dysfunction of gonadotropin secretion, the control of PRL secretion was disturbed in this disease since there was a poor PRL response to chlorpromazine in spite of normal responsiveness to TRH. Thus, "isolated gonadotropin deficiency" hitherto used to describe this disease is not pertinent. Furthermore, these results suggest that PRL might be involved in the onset of puberty in humans. Clinically, the induction of ovulation with HMG (Human Menopausal Gonadotropin) is possible in hypothalamic primary amenorrhea, although the ovarian responsiveness to gonadotropin is poor. Therefore, an endocrinologically precise diagnosis of hypothalamic primary amenorrhea is important in the gynecological clinic because fertility has been considered to be almost impossible in primary amenorrhea.

Amenorrhea↗
PubMed1982

Synthesis and secretion of prolactin in the decidualized human endometrium unassociated with pregnancy in vitro.

The effect of the decidualization induced by the administration of sex steroid hormones on the human endometrial PRL contents and the mechanism of synthesis and secretion of PRL in this decidualized endometrium of non-pregnant women were investigated. The PRL contents increased in proportion to the degree of decidualization. In vitro secretion of PRL in decidualized human endometrium was inhibited by the protein synthesis inhibitors, while TRH, dopamine, and bromocriptine did not have any effects on PRL secretion in incubation experiments. These data suggest that the production and secretion of PRL in the human endometrium have no relation to the presence of conceptus, and furthermore, they are regulated by mechanism different from the pituitary PRL.

Cycloheximide↗
PubMed1982

[Fundamental and clinical studies of piperacillin in the field of obstetrics and gynecology].

We conducted experimental and clinical tests on piperacillin (PIPC), a drug with a broad antibacterial spectrum, and achieved the following results. PIPC exhibited the following rather high therapeutic blood concentrations: 30--60 micrograms/ml at 1 hour after intravenous injection of 1 g of PIPC, 10 micrograms/ml at 2 hours after intravenous injection of 2 g of PIPC, 7.2 micrograms/ml at 1 1/2 hours after the completion of 1 hour dripping infusion of 1 g of PIPC, and 5.6 micrograms/ml up to 4 hours after the completion of 2 hours dripping infusion of 2 g of PIPC. The yield to the various uterine tissues is presented in decreasing order: the highest yield to ovary was about 40--50% of the blood level, followed by the uterine cervical region, portio vaginalis, myometrium and oviduct, the lowest yield, about 25--30% of the blood level was found in endometrium. We conducted a clinical test on 7 patients with infections of the sexual organs and it proved to be excellent in 3, good in 3, and ineffective in 1 case so that the overall efficacy rate was 85.7%. The patient in whom PIPC proved ineffective suffered from an underlying disease, namely the end stage of cervical cancer. One patient suffered from a slight headache but whether this side effect was due to administration of the drug is not clear. Absolutely no abnormal findings during laboratory tests which could be attributed to drug administration were made. Based on the above results, PIPC was judged to be an extremely useful drug in the treatment of infections in the obstetric and gynecological fields.

Adult↗
PubMed1982

Effects of sex steroid hormones on rat anterior pituitary LH-RH receptor.

In order to elucidate the mechanism of estrogen action at the anterior pituitary level, the effects of estradiol on the number of binding sites of LH-RH receptor in the anterior pituitary as well as its effects on the anterior pituitary responsiveness to LH-RH were studied in castrated adult female rats. Daily sc injections of 20 micrograms of 17 beta-estradiol for 2 and 4 days increased both LH-RH receptor levels and the responsiveness of the pituitary to LH-RH. This result indicates that estrogen modulates the sensitivity of the anterior pituitary to LH-RH by changing its LH-RH receptor.

Animals↗
PubMed1982

[A new method of ovulation induction with HMG-HCG by a E2 rapid radioimmunoassay (author's transl)].

We schemed out a new method of ovulation induction with HMG-HCG using E2 rapid radio-immunoassay (RIA). On measurement of E2 values, the method of E2-(125)I kit (Daiichi Radioisotope Labs., LTD) was simplified, that is, an omission of defatting, shortened incubation time and a standard curve constructed by three points. There was a good correlation between the E2-(125)I kit method and the E2 rapid RIA method in E2 values obtained. The lowest detectable amount was 75 pg/ml. This rapid method seemed to be suitable to monitor the extent of follicular maturation during HMG therapy. Our new method of ovulation induction was as follows. (i) On the basis of E2 values measured every 3 days, HMG dosage was adjusted. (ii) When E2 was over 400 pg/ml for 2 days, HCG was given on the next day. with this method, there was an increase in the percentage of ovulatory cycles from 54.5% to 100% and a decline in the incidence of ovarian enlargement and the ascites. This new method minimized inconvenience and expense of E2 determination without drastically influencing therapy outcome.

Adult↗
PubMed1981

Cellular immunity in normal pregnancy and abortion: subpopulations of T lymphocytes bearing Fc receptors for IgG and IgM.

Studies on the change of peripheral T and B lymphocytes and T cells bearing Fc receptors for IgG (IgG.FcR+.T lymphocytes) and IgM (IgM.FcR+.T lymphocytes) in normal pregnant women and patients with threatened abortion were performed by using rosette-formation tests. There was no significant difference in the proportion of T and B lymphocytes between pregnant and nonpregnant women. The percentage change of T cells of the patients in threatened abortion with good prognosis was significantly decreased and that of B cells of the patients in threatened abortion was significantly increased compared with that of normal pregnant women. The percentage of IgG.FcR+.T lymphocytes in the T lymphocytes increased in the various stages of pregnant and postpartum women as compared with that in nonpregnant women, and in the case of the patients with threatened abortion it also increased significantly from that of normal pregnant women. On the contrary, the percentage of IgM.FcR+.T in the T lymphocytes decreased in normal pregnant and postpartum women.

Abortion, Threatened↗
PubMed1981

Stimulatory effect of chlorpromazine on prolactin secretion in anencephalic infants.

The effect of chlorpromazine on serum levels of PRL was studied in two anencephalic infants without identifiable hypothalamic tissue. After a single im injection of chlorpromazine, serum concentrations of PRL rose about 3-fold. This result indicates that chlorpromazine stimulates PRL release by directly acting on the pituitary gland in humans.

Anencephaly↗
PubMed1981

Effect of prolactin on the secretion of dehydroepiandrosterone (DHEA), its sulfate (DHEA-S), and cortisol by the human fetal adrenal in vitro.

The effect of prolactin on the secretions of dehydroepiandrosterone (DHEA) and its sulfate (DHEA-S) as well as that of cortisol were studied in vitro in order to investigate the possible regulatory role of prolactin on steroidogenesis of the human fetal adrenal at mid-gestational age. The addition of 0.5 microgram/ml of human prolactin to the incubation medium produced a significant (P less than 0.05) increase in DHEA, DHEA-S, and cortisol secretion. These results indicate that prolactin has a regulatory role in steroidogenesis in the human fetal adrenal at mid-gestation.

Adrenal Glands↗
PubMed1981

Synthesis of prolactin by human decidua in vitro.

Human decidua, chorion, amnion and placenta from the 1st., 2nd. and 3rd. trimesters of gestation were investigated for synthesis and secretion of prolactin by in vitro incubation of these tissue fragments in medium 199. Prolactin content in decidua was found to be significantly higher than that in chorion, amnion or placenta at any stages of gestation. During 6 hours of incubation, decidua secreted significantly more prolactin into medium than did chorion, amnion or placenta. The amount of prolactin secreted by decidua was significantly higher than the prolactin content in tissue before incubation. Decidua were also incubated in medium 199 with or without actinomycin-D (20-200 micrograms/ml), puromycin (200 micrograms/ml) or cycloheximide (100-200 micrograms/ml) for 12 hours. Both total prolactin secreted into medium and prolactin content in tissue after incubation were significantly lower than the control without inhibitor. Decidua of 2nd. trimester of gestation was noted to secrete more prolactin into medium than decidua of 1st. or 3rd. trimester of gestation. In further studies, 3H-leucine (200 muCi) was incubated for 12 hours with decidua (10 grams) from 2nd. trimester of gestation. The incorporated protein in medium or tissue was extracted, fractionated by gel filtration through Sephadex G-100 column and by 10% SDS-polyacrylamide gel electrophoresis. Peaks of 3H count and immunoreactive prolactin in gel slices were coincident with the peak of standard pituitary prolactin at gel slices' No. 31 (Rf = 0.62). These results demonstrate that prolactin is synthesized and secreted by human decidua, which is identical to human pituitary prolactin. The synthetic activity is most prominent in the decidua of the 2nd. trimester of pregnancy.

Amnion↗
PubMed1980

Effect of hypothalamic deafferentation on the distribution of luteinizing hormone-releasing hormone (LHRH) in the rat brain.

Anterior (AHD) and complete hypothalamic deafferentation (CHD) were performed in female rats to ascertain the origin of LHRH detected in the external layer of ME. Deafferented brains were serially sectioned in a cryostat in the frontal plane. LHRH activity in each section was determined by RIA. While AHD, using a knife with a small radius caused no change in the distribution of LHRH in the brain, AHD, using a knife with a large radius resulted in a significant decrease in LHRH content in the ARC-ME. CHD caused a more marked decrease in the ARC-ME LHRH than AHD. The decrease was more marked in the anterior and posterior portions of the ARC-ME than in the middle one. These effects of CHD on the distribution of LHRH in the ME were ascertained by immunohistochemical studies. In contrast, LHRH content in the POA showed no significant change after AHD and CHD. However, a few LHRH containing fibers were observed in the area lying just proximal to the cut by immunohistochemistry. These results strongly suggest that a part of the LHRH detected in the external layer of ME is derived from that synthesized outside the MBH, possibly in the POA and another part is derived from that synthesized inside the MBH, possibly in the ARC.

Afferent Pathways↗
PubMed1979

Distribution of LHRH in the rat and mouse brain with special reference to the tanycytes.

The distribution of luteinizing hormone-releasing hormone (LHRH) was studied in the rat and mouse brain by means of light and electron microscopic immunohistochemistry using the peroxidase-antiperoxidase method. An immunoreactive product to LHRH antiserum was found near the blood vessels of the vascular organ of the lamina terminalis. In the arcuate nucleus-median eminence region, an immunoreactive material occurred bilaterally in the hypothalamic tissue around the tuberoinfundibular sulci. Electron microscopy revealed that immunoreactive fibers observed light microscopically contain numerous granules 100--130 nm in diameter. No immunoreactive product was located in the tanycytes of the median eminence, the perikarya of hypothalamic neurons, and the parenchyma of several circumventricular organs (subfornical organ, subcommissural organ, pineal organ, area postrema).

Animals↗
PubMed1976

Changes of serum gonadotropin concentrations in fetal and neonatal rat following castration.

Changes of serum concentrations of LH were measured in fetal and neonatal rats following castration. Intact fetal and neonatal male rats showed low levels of serum LH concentration. Though serum LH levels of male rats casterated on the 20th day of gestation did not significantly increase by the 22nd day of fetal age, serum levels of neonatal male rats increased 2-to 3-fold 3 days following castration at all ages studied. The increase was greater in 4-day-old male rats than in 1-day-old males. The increase of serum LH after castration was also found in 4-day-old male rats castrated on the 20th day of gestation. In contrast, serum levels of 1-day-old neonatal female rats did not increase 3-days after castration. These observations suggest sex differences in maturation of the gonadal-hypophyseal feedback mechanism.

Animals↗