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Biomedical subjects

T Kigawa

Publications and source records attributed to T Kigawa.

At least 55 records · Page 3Linked to original sources
PubMed1985

[The effects of bromocriptine on the pulsatile pattern and the circadian profile of gonadotropins and testosterone secretion in normal adult men].

To investigate the effects of bromocriptine on the secretion mechanism of pituitary gonadotropins and testosterone, 5 mg of bromocriptine was administered to five young adult men who were normal in their endocrinological states. Blood samplings were taken from two hours before until six hours after the administration every 15 min., and after that, blood samplings were continued until 21 hours every one hour by an intravenous indwelling catheter. Serum FSH, LH, prolactin and testosterone levels were determined by RIA, and the changes of the pulsatile patterns of FSH and LH, and the circadian profile of these hormones by the administration of bromocriptine were analysed. Serum prolactin levels decreased significantly (p less than 0.005) from two hours after the administration of bromocriptine and remained in a very low range until the end of the experiment. The basal levels of FSH showed a significant decrease from two to six hours after the administration (p less than 0.005). Also the basal levels of LH showed a significant decrease from two to six hours after the administration (p less than 0.005). However, the basal levels of serum FSH and LH did not show significant decreases after that until the end of the experiment. No significant change was observed in the amplitude or the frequency of the pulsatile patterns of FSH and LH until six hours after the administration of bromocriptine. The serum levels of testosterone were also significantly decreased from two to six hours after the administration (p less than 0.005), but they did not show a significant decrease after that until the end of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[The mechanism of induction of ovulation by bromocriptine in euprolactinemic anovulation--the role of occult hyperprolactinemia in anovulation].

It has been well documented that ovulation was induced by Bromocriptine treatment in euprolactinemic anovulation. The present study has been carried out to clarify the underlying mechanism. 28 patients with euprolactinemia (PRL less than 25 ng/ml) were treated with a 5 mg daily administration of Bromocriptine. Ovulation was induced in 13 cases, which were determined by their BBT charts. In the ovulated cases, PRL secreting capacities were increased, determined by TRH administration. On the other hand, PRL secreting capacities were normal in the anovulated cases. The studies of the circadian secretion of PRL revealed that a nocturnal hyperprolactinemic state occurred for several hours in the ovulated cases, which was not seen in the anovulated cases. From these results, the mechanism of induction of ovulation by Bromocriptine in euprolactinemic anovulation exists on the suppression of the increased PRL secreting capacity, which may be related to the occulted hyperprolactinemia at night. Ovulated cases by Bromocriptine are seemingly euprolactinemia, but in truth they may be a kind of hyperprolactinemia.

Adult↗
PubMed1985

[The effects of bromocriptine on anovulatory patients with high LH and euprolactinemia].

It is well known that an acute administration of Bromocriptine (dopamine agonist) suppresses the serum LH level either in normal women or in women with polycystic ovary syndrome, in whom the serum LH level is elevated. The present study was carried out to examine the effectiveness of Bromocriptine on anovulatory women with a high LH level (serum LH greater than 30 mIU/ml). Bromocriptine was administered for 3 months, 5 mg daily, to 9 anovulatory women with euprolactinemia (serum PRL less than 25 ng/ml). Ovulation was observed by their BBT charts. Before and after the treatment of Bromocriptine, FSH, LH and PRL secreting capacities were tested by LHRH and TRH injection. Also, estrone, estradiol and testosterone levels were measured before and after the Bromocriptine administration. Resting levels of LH, FSH and PRL were 45.4 +/- 11.0 mIU/ml, 11.4 +/- 3.0 mIU/ml, and 14.3 +/- 4.7 ng/ml (M +/- SD), respectively, before the treatment. As a result of the treatment, the LH level was markedly decreased to 27.3 +/- 14.5 (M +/- SD, P less than 0.05), and PRL decreased to 3.76 +/- 4.2 ng/ml (M +/- SD, P less than 0.005). On the other hand, FSH did not show a marked change. The responsiveness of LH to LHRH before the treatment showed a marked increase, which was suppressed by Bromocriptine. However, FSH showed no change. The responsiveness of PRL to TRH was suppressed by Bromocriptine. Serum estrone, estradiol and testosterone levels before the treatment were 115.5 +/- 76.7 pg/ml, 93.7 +/- 61.0 pg/ml and 0.809 +/- 0.209 ng/ml (M +/- SD), respectively, which showed no significant change after the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Effects of mother-infant interaction on maternal milk secretion and dynamics of maternal serum prolactin levels in puerperium].

Effects of maternal-infant interaction on maternal milk secretion and the dynamics of maternal serum prolactin levels in puerperium were examined in 183 normally delivered mothers without any complications. No significant change was observed in the amount of maternal milk secretion between the primiparas and the multiparas. However, there was a significant increase in the amount of maternal milk secretion in the breast feeding group compared to the supplementary feeding group from the second to the sixth day of the puerperium (p less than 0.005). Moreover, the amount of maternal milk secretion increased significantly in the group that adopted the rooming-in system compared to the non rooming-in group (p less than 0.005). And also the significant increase occurred in the encouragement of breast feeding following the adoption of the rooming-in system (x2 = 7.244, p less than 0.01). There was no significant correlation between the amount of maternal milk secretion and the puerperal maternal prolactin levels, but the maternal serum prolactin level at 24 hours after delivery was significantly higher in the breast feeding group than in the supplementary feeding group (p less than 0.01). Also, the maternal serum prolactin was increased by the stimulation of the baby crying the same as by suckling or manual expression. These facts suggest that the maternal-infant bonding plays the important role in the encouragement of the breast feeding and the maternal serum prolactin may have some actions on the mechanism of maternal milk secretion.

Animals↗
PubMed1985

[Correlation of prolactin-secreting-capacity to circadian profile of prolactin in euprolactinemic women with ovulatory disturbances].

Circadian profile and responsiveness of prolactin to TRH administration were examined in 21 women with ovulatory disturbances. The data were analyzed with reference to the clinical effectiveness of bromocriptine administration. Resting levels of serum prolactin in the patients studied were lower than 25 ng/ml. 14 patients out of 16 cases (Group A) responded to bromocriptine, whose prolactin levels were more than 30 ng/ml during the night in the circadian studies. On the other hand, none of 5 patient (group B) responded to bromocriptine, whose prolactin levels were not more than 30 ng/ml during the night. Group A showed hyper-responsiveness of prolactin to TRH higher than that of Group B. These results suggested that 1) In euprolactinemic ovulatory disturbances there are cases with nocturnal hyperprolactinemia, whose prolactin levels are normal during the day time. These cases will be referred to as occult hyperprolactinemia. 2) Those with occult hyperprolactinemia show increased prolactin-secreting-capacity, which is able to be diagnosed by the hyper-responsiveness of prolactin to TRH administration. 3) The effectiveness of bromocriptine in treating euprolactinemic ovulatory disturbances is due to the suppressive effect of bromocriptine on the hyperprolactinemic states of occult hyperprolactinemia.

Adult↗
PubMed1984

[The effects of dopamine agonist (bromocriptine) on the secretion of pituitary gonadotropins and ovarian sex steroids in normally cycling women].

To investigate the effects of bromocriptine on the secretion mechanism of pituitary gonadotropins and ovarian sex steroids, 5 mg of bromocriptine was administered to four normally cycling women in the follicular, pre-ovulatory, mid-luteal or menstrual phase, respectively. Blood samplings were taken from two hours before until six hours after the administration every 15 min. by an intravenous indwelling catheter. Serum FSH, LH, prolactin, estradiol and progesterone were determined by RIA, and the changes of basal levels and the pulsatile patterns of these hormones were analysed in each of the four phases. Serum prolactin levels decreased significantly (p less than 0.005) from two hours after the administration of bromocriptine and remained in a very low range in all phases of the cycles until the end of the experiments. The basal levels of FSH showed a significant decrease in the pre-ovulatory and mid-luteal phases two to six hours after the administration (p less than 0.025 approximately p less than 0.005). Also the basal levels of LH showed a significant decrease in the follicular, pre-ovulatory and mid-luteal phases two to six hours after the administration (p less than 0.05 approximately p less than 0.005). However, no significant change was observed in the amplitude or the frequency of the pulsatile patterns of FSH and LH in all phases of the menstrual cycles. The serum levels of estradiol did not show marked changes by the administration of bromocriptine, but the serum levels of progesterone were significantly decreased in the mid-luteal phase two to six hours after the administration (p less than 0.005). These facts suggest that bromocriptine acts mainly on the pituitary rather than the hypothalamus to decrease the serum levels of gonadotropins, and also may have some role in the steroidogenesis of the ovary.

Bromocriptine↗
PubMed1984

Normal organic and inorganic mercury levels in the human feto-placental system.

To clarify the normal metabolism of mercurials in the human feto-placental system, organic (or methyl) mercury and inorganic mercury were measured in maternal blood (MB), umbilical cord blood (UB), and chorionic tissues of the placenta (PC) and its blood vessels (PV), obtained from pregnant women just after delivery, as well as in fetal liver and fetal brain from induced abortion cases. Organic mercury was commonly detected in MB, UB, PC and PV, with slightly more elevated values in UB and PC than in MB, whereas inorganic mercury was detected in PC and PV, but not in MB and UB. In the fetal liver, 27-60% of mercury was in the form of inorganic mercury, whilst in four of five fetal brain samples, inorganic mercury was not detected. Additionally, fetal liver demethylation activity was studied in vitro. Incubation of methyl mercury with chopped fetal liver tissue for 24 h resulted in demethylation of approximately 1% of the methyl mercury.

Dealkylation↗
PubMed1984

Effects of dehydroepiandrosterone-sulphate (DHEA-S) administration on puerperal lactation and maternal prolactin and estradiol levels.

Effects of dehydroepiandrosterone-sulphate (DHEA-S) on puerperal lactation and maternal serum prolactin and estradiol levels were examined in 111 cases of normal vaginal delivery without any complication. The amount of lactation in the DHEA-S administrated group was significantly decreased on the second day of the puerperium (p less than 0.05). No significant difference could be found after the third day of the puerperium, or in the total amount of lactation up to the seventh day of the puerperium. There was also no significant difference in the changes in neonatal body weight. No significant change was observed in maternal serum prolactin levels following DHEA-S administration. But the maternal serum estradiol levels were significantly higher at 0, 6, 12, 24 and 36 hours after delivery following the administration of DHEA-S (p less than 0.05 approximately 0.005). These facts suggested that the transient inhibition of lactation by DHEA-S may be caused by the effect on mammary glands of estrogens which were converted from DHEA-S in the placenta.

Dehydroepiandrosterone↗
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

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↗
PubMed1981

[Effects of bromocriptine on FSH and LH secretion in women with euprolactinemic anovulation (author's transl)].

A few reports have been given that Bromocriptine effected not only on the hyperprolactinemic anovulations but also on the euprolactinemic anovulations. This study was performed to examine the underlying mechanism, 5 mg of Bromocriptine was daily administered for 30 days to 38 women with euprolactinemic anovulations. The basal secretions of FSH, LH and Prolactin and also the responsiveness to LH-RH, TRH and estradiol were examined. 31.6% of oligomenorrhea, anovulatory cycle and Ist. grade amenorrhea showed ovulatory cycles, however, no ovulations were observed in IInd. grade amenorrhea. The basal levels of FSH and LH significantly increased but the basal levels of Prolactin decreased by Bromocriptine. The responsiveness of FSH to LH-RH was markedly promoted but LH showed no significant change. Serum FSH was suppressed in estrogen loading test after Bromocriptine, which was poorly changed before. On the other hand, serum LH was markedly elevated by estradiol after Bromocriptine, which showed poor elevation before. These results conclude that: 1) Ovulation is induced by Bromocriptine administration in euprolactinemic anovulations. 2) Bromocriptine promotes the FSH and LH secretion from the pituitary and also promotes the reserve of FSH in the pituitary. 3) Bromocriptine promotes the sensitivity of the estrogen feedback in the hypothalamus.

Adolescent↗
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↗