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K Aida

Publications and source records attributed to K Aida.

At least 145 records · Page 8Linked to original sources
PubMed1989

Effects of chronic LHRH-a + 17-methyltestosterone or LHRH-a + testosterone therapy on oocyte growth in the striped mullet (Mugil cephalus).

The striped mullet (Mugil cephalus) exhibits a restricted spawning season and matures only once per spawning cycle. In vivo monitoring of ovarian maturation of individual females during the season reveals that timing of full maturity varies. A small percentage of females that mature early can be induced to spawn and will remature. Such females can be spawned a second time within the same season. Chronic administration of luteinizing hormone-releasing analog (LHRH-a) + testosterone results in accelerated egg growth. The majority of females undergoing this therapy mature at least a month before control fish. When these females are induced to spawn, a higher percentage remature and can be spawned again. The double spawnings of both control and LHRH-a + testosterone-treated females occur without any appreciable loss in egg quality. Administration of LHRH-a + 17 alpha-methyltestosterone essentially inhibits egg growth. Steroid profiles from females undergoing this therapy exhibit a significant drop in circulating testosterone and estradiol 17 beta, compared to control and LHRH-a + testosterone-treated females. Hypotheses for the poor performance of this therapy are discussed.

Animals↗
PubMed1989

Melatonin secretion from goldfish pineal gland in organ culture.

Pineal glands were removed from goldfish reared under 12L-12D at 25 degrees for 2 weeks. These were incubated for 6 days under (1) normal 12L-12D (lights on 0600-1800 hr), (2) reversed 12L-12D (lights on 1800-0600 hr), (3) continuous dark, or (4) continuous light condition at 25 degrees. The incubation medium was changed at 12-hr intervals (0600-1800 and 1800-0600 hr) and secreted melatonin (MLT) was measured by RIA. Under 12L-12D or reversed 12L-12D, MLT secretion was active in the dark phase and was suppressed in the light phase of a given photoperiod. Under a continuous dark condition, a large amount of MLT was secreted into the medium, although the amount gradually decreased. The MLT secretion was more active in the period corresponding to the dark phase of the acclimatory photoperiod than in the period corresponding to the light phase. This pattern in secretion remained for 4 days. Under a continuous light condition, MLT secretion was suppressed, but the secretion was rapidly increased after changing the photoperiod from the light to the dark condition. These findings clearly indicate that MLT secretion in the organ-cultured pineal gland is photosensitive. It is active under dark and inactive under light conditions. The existence of a circadian rhythm in MLT secretion is also suggested.

Animals↗
PubMed1989

Development of sensitivity to maturation-inducing steroids and gonadotropins in the oocytes of the tobinumeri-dragonet, Repomucenus beniteguri, Callionymidae (Teleostei).

The effectiveness of steroids and gonadotropins (GtHs) in inducing final oocyte maturation was examined at different times of the day (0100, 0500, 0700, 0900, 1100, 1300, 1700, 2100 hr) in a daily spawning marine teleost, the tobinumeri-dragonet, Repomucenus beniteguri. The responsiveness of oocytes to GtHs and steroids was different at various times of day. The sensitivity of oocytes to hormones was apparent only during a certain period of the day (0100-0900 hr). Germinal vesicle breakdown (GVBD) could be induced by GtHs but not by steroids at 0100 hr. At 0500 hr, not only GtHs but also steroids at higher doses induced GVBD and ovulation. Oocytes underwent GVBD and ovulation at low doses of steroids at 0900 hr. GVBD and ovulation spontaneously occurred at 1100 and 1300 hr without any hormonal treatment. In addition, diameter and histological changes of ovarian oocytes were investigated. Ovarian oocytes were smaller than 420 microns, and only one oocyte group existed in distribution of oocyte frequency at 2100 and 0100 hr. With the increase in size of oocytes, two distinct groups appeared at 0500 hr. Larger oocytes completed GVBD at 1100 hr. Ovulation occurred between 1300 and 1700 hr and oviposition was completed between 1700 and 2100 hr daily. These results clearly show that the oocyte of the dragonet possesses a daily maturation rhythm. Responsiveness of oocytes to GtHs appeared earlier than responsiveness to steroids. This suggests that sensitivity to steroids is induced by GtH.

17-alpha-Hydroxypregnenolone↗
PubMed1989

Induction of gonadotropin surge by steroid hormone implantation in ovariectomized and sexually regressed female goldfish.

Involvement of steroid hormones in the occurrence of the ovulatory gonadotropin (GtH) surge was studied in goldfish. Ovariectomized female goldfish were implanted with an empty Silastic capsule or a capsule containing testosterone or estradiol, and kept below 12 degrees for 3 months (Experiment 1). Some of the steroid implanted fish showed a GtH surge which was quite similar to the normal ovulatory GtH surge in response to a water temperature rise from 12 to 20 degrees, whereas no surge was observed in fish with empty capsules. When sexually regressed female goldfish were implanted with the capsules containing testosterone or estradiol and kept at 12 degrees for 6 weeks out of spawning season, the GtH surge was also observed in these fish after the water temperature rise to 20 degrees (Experiment 2). The GtH surge was observed in a larger number of testosterone-implanted fish than in the estradiol-treated fish in both experiments. These results strongly suggest that the high plasma level of testosterone observed before ovulation is an important physiological requisite for the occurrence of the ovulatory GtH surge in goldfish.

Animals↗
PubMed1989

The existence of aldose reductase inhibitors in some kampo medicines (Oriental herb prescriptions).

Traditionally in Japan, some kampo medicines which contain Glycyrrhizae radix (GR) and Paeoniae radix (PR) have long been used for the treatment of diabetic neuropathy. Since we have previously shown that GR und PR have potent aldose reductase inhibitory activities, we further investigated the constituents of these two. The boiled water extract of GR was applied to Sephadex LH-20 column chromatography and 6 fractions (Frs. A, B, Cs, Cp, D, and E) were obtained. Frs. Cp and D were retreated in the same manner and 7 pure compounds (GUs 1-7) were obtained. The boiled water extract of PR was fractionated with ethyl acetate followed by n-butanol and 3 fractions (Frs. 1-3) were collected. Fr. 1 was retreated in the same manner and 2 pure compounds (PRs 1 and 2) were obtained. Among the GU compounds, GU-2 was the most potent inhibitor of rat lens aldose reductase (RLAR) by inhibiting 86% at the concentration of 1.0 microgram/ml. The IC50 of GU-2 was 7.2 x 10(-7) M. Furthermore, GU-2 markedly inhibited sorbitol accumulation in human red blood cells, having an IC50 of 2.9 x 10(-5) M. GU-5 and PR-1 also inhibited RLAR (IC50: 5.6 x 10(-7) M and 6.3 x 10(-7) M, respectively). The structures of GU-2, GU-5, and PR-1 were identified as isoliquiritin, licuraside, and 1, 2, 3, 6-tetra-O-galloyl-beta-D-glucose, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Reductase↗
PubMed1989

[Acute cerebellar ataxia and facial palsy after DPT immunization].

Since the initial report of Beyers & Moll (1948), numerous cases of seizures and encephalopathy after pertussis immunization or DPT immunization have been reported. However, acute cerebellar ataxia and/or facial palsy after DPT immunization is unusual, although there have been several reports from Japan. We report a 1-year-11-month-old girl with acute cerebellar ataxia and facial palsy after DPT immunization. On admission, she was alert. She was active and had a 6-day history of an ataxic gait and asymmetric facial movement which had begun 5 hours after DPT immunization. Neurological examination revealed an ataxic gait, horizontal nystagmus and right facial palsy. A CT scan showed low density on the right side of the pons with marked contrast enhancement. A MRI scan indicated the involvement of not only the right side of the pons, but also of the bilateral cerebellar peduncles. The child did well subsequently and was neurologically normal 20 days after the initial symptoms. To our knowledge, the present case is probably the first reported one of acute cerebellar ataxia after DPT immunization with CT and/or MRI correlation.

Acute Disease↗
PubMed1988

Hormone changes during the ovulatory cycle in goldfish.

Hormone profiles during the ovulatory cycle were studied in goldfish. Blood samples were taken from female goldfish every 4 days between 1400 and 1700 hr during the course of repeated ovulations for a duration of 3 months, and plasma hormone levels of 3 days before and after ovulation were compared. Plasma gonadotropin (GtH) levels did not show significant changes except a surge for ovulation, but tended to show higher levels before the surge than those after the surge. Plasma testosterone before ovulation showed significantly higher levels compared with those after ovulation. Plasma estradiol-17 beta (E2) levels remained low for 3 days prior to ovulation. Postovulation E2 levels that were significantly higher than the preovulation levels were kept elevated and declined on the third day after ovulation. These results indicate that E2 is mainly produced in the first part of the ovulatory cycle and testosterone in the latter part followed by the GtH surge and ovulation at the end of the cycle. This shift in steroid pattern from E2 to testosterone seems to be similar to those observed in salmonid fishes except for the time scale. The synchrony of ovulation in goldfish is also discussed in relation to physiological and external factors which influence the occurrence of ovulation.

Animals↗
PubMed1988

Development of sensitivity to maturation-inducing steroids in the oocytes of the daily spawning teleost, the kisu Sillago japonica.

The responsiveness of oocytes to 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOH-P), 17 alpha-hydroxyprogesterone (17 alpha-OH-P), and silver carp gonadotropin (GtH) was examined in vitro at seven different times of the day (0100, 0500, 0800, 1000, 1300, 1700, 2100 hr) in a daily spawning teleost, the kisu Sillago japonica. 17 alpha,20 beta-DiOH-P, 17 alpha-OH-P, and GtH were effective in inducing germinal vesicle breakdown (GVBD) and ovulation in kisu oocytes. However, the oocytes of the kisu responded to these hormones during a limited time of the day (2100-1000 hr), and their responsiveness to steroids and GtH was different with the sampling time. After a 20-hr incubation, the oocytes with yolk globules were classified into four stages based on their responses (GVBD) to GtH and steroids. Stage A, the oocytes did not respond to either GtH or steroids. These unresponsive oocytes were observed in all the ovaries examined. Stage B, GVBD could be induced by GtH but not by steroids. These oocytes were found in the ovaries collected from 2100 to 1000 hr. Stage C, GVBD could be induced by both GtH and steroids. These oocytes were found only between 0800 and 1000 hr. Stage D, oocytes spontaneously underwent GVBD without hormones. These oocytes were found between 1300 and 1700 hr. Ovulated oocytes were found in the ovaries collected during 1700-0500 hr. These results indicate that the kisu possesses a daily rhythm in oocyte development from stage A to stage D, and that the sensitivity to 17 alpha,20 beta-diOH-P appears at stage C.(ABSTRACT TRUNCATED AT 250 WORDS)

17-alpha-Hydroxyprogesterone↗
PubMed1988

Daily cycles in plasma melatonin levels under long or short photoperiod in the common carp, Cyprinus carpio.

A radioimmunoassay (RIA) for plasma melatonin (MLT) was simplified for use with the common carp (Cyprinus carpio). Plasma was partially purified with Sep-Pak C18 cartridge before RIA. The inhibition curves for the Sep-Pak C18 fraction from the plasma of carp, goldfish (Carassius auratus), yellow tail (Seriola quinqueradiata), Japanese eel (Anguilla japonica), bora (Mugil cephalus cephalus), kisu (Sillago japonica), ishigarei (Kareius bicoloratus), and shimaisaki (Rhyncopelates oxyrhynchus) were parallel with the MLT standard curve. There was a highly significant correlation between MLT added to carp plasma and that which was recovered (r = 0.997, P less than 0.01). Intraassay coefficients of variation at low, medium, and high levels were 4.7, 5.2, and 6.4, respectively. Interassay coefficients of variation at low, medium, and high levels were 11.8, 8.2, and 24.1%, respectively. The lower limit of detection was 11 pg/tube. Plasma MLT levels were investigated every 2 hr in carp under 16L-8D and 8L-16D at 24 degrees. Under both photoperiods, MLT levels showed marked daily patterns, i.e., the levels were high (220-540 pg/ml) during the dark phase and low (23-104 pg/ml) during the light phase. Tricaine methanesulfonate markedly interfered with the MLT measurements, while ethylcarbamate did not show any significant influence. Sexual difference in plasma MLT levels in carp was not observed. These observations suggest that MLT is an important hormone in photoperiodism and/or a circadian rhythm in fish.

Anesthetics↗
PubMed1987

Hormone changes during ovulation and effects of steroid hormones on plasma gonadotropin levels and ovulation in goldfish.

Plasma hormone changes during ovulation and the effects of steroid hormones on plasma gonadotropin (GtH) levels and ovulation were studied in the female goldfish. Ovulation was induced by raising water temperature from 12 to 20 degrees. Plasma gonadotropin levels exhibited a gradual rise during the latter half of the light phase. This was then followed by a surge in GtH, showing a peak at the time of ovulation in the dark phase. After ovulation, GtH levels decreased rapidly by the next light phase. Plasma 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOH-P) and testosterone showed a peak before ovulation, and then decreased by the time of ovulation. Estradiol-17 beta (E2) showed moderate levels during the GtH surge. No marked decrease of E2 levels was observed before the commencement of the GtH surge. Administration of testosterone or E2 prior to elevating the water temperature did not inhibit the occurrence of the GtH surge and ovulation. Likewise, administration of neither 17 alpha-hydroxyprogesterone nor 17 alpha,20 beta-diOH-P affected plasma GtH levels at 20 degrees. The present study shows a clear picture of the hormone changes that occur during spontaneous ovulation in goldfish. The results of administering steroids prior to ovulation does not support the hypothesis that a decline in E2 levels triggers the GtH surge and ovulation.

Animals↗
PubMed1987

Effects of sex steroids on the smoltification of masu salmon, Oncorhynchus masou.

Testosterone (T; 25-micrograms/g diet), estradiol-17 beta (E2; 2.5-, 25-micrograms/g diet), and 5 alpha-dihydrotestosterone (DHT; 2.5-, 25-micrograms/g diet) were administered to yearling masu salmon from February 3 through May 8. T and E2 inhibited the natural smoltification in spring and stimulated gonadotropin (GtH) accumulation in the pituitary, but DHT had no effect. T (25-micrograms/g diet) was administered to underyearling masu salmon from September 30 through December 14. At the end of the T treatment, fish body color darkened and pituitary GtH content increased in the T-treated group. On May 8 in the next spring, however, plasma T levels and pituitary GtH contents already decreased and smoltification occurred in both control and T-treated groups. On October 29, underyearling masu salmon reared under the short daylength (8 L:16 D) for 4 months were switched to a long daylength (16 L:8 D) and simultaneously administered with T (25-micrograms/g diet) or 11-ketotestosterone (11-KT; 25-micrograms/g diet). On December 17, the proportion of smolts was 52.8% in the control, whereas T and 11-KT administration inhibited smoltification under the artificially increased daylength. Pituitary GtH content significantly increased both in the T-treated and 11-KT-treated groups, though it was much lower in the latter. These results indicate that the springtime smoltification which is induced by increasing daylength is inhibited by biologically active sex steroids such as E2, T, and 11-KT.

Animals↗
PubMed1987

Critical daylength and temperature level for photoperiodism in gonadal maturation of goldfish.

When yearling goldfish were exposed to 12, 13, 14, 15 or 16 L at 24 degrees C from 27 October-27 December, females were suppressed at 12 or 13 L but matured to spawn at other daylengths. The critical daylength was thus located at 13-14 L. Males were not suppressed at any daylength, and spermiated to pass quickly into the post-spawning stage, commencing the next maturation cycle after completion of the regressive stage. When exposed to 12 or 16 L at 18 or 21 degrees C from 5 December-5 March, a few females matured and spawned at 21 degrees C/12 L, while most females did so on other regimes. The temperature level, below which the photoperiodic response became indistinct, was between 18 degrees and 21 degrees C. Most males continued spermatogenesis at 18 degrees C/16 L, but they spermiated and passed into the post-spawning stage quickly on other regimes.

Animals↗
PubMed1986

Endocrine profiles in the males of a twice-annually spawning strain of rainbow trout, Salmo gairdneri.

The male reproductive cycles of a twice-annually spawning strain of rainbow trout were studied by monitoring the plasma gonadotropin (GtH) and steroid hormone levels in individual fish for more than a year using thirty-five 2.5-year-old mature males. Twenty-five males survived the whole experimental period and were divided into four groups according to the amount of milt and endocrine profiles. In the summer breeding season, milt amount was negligible in Group I and small in Group II with low plasma testosterone, 11-ketotestosterone (11-KT), and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOH-P) levels, whereas both groups showed a large amount of milt and a distinct increase in steroid levels in the winter breeding season (November-January). Group III expelled a large amount of milt in both the summer and winter breeding seasons, and plasma testosterone, 11-KT, and 17 alpha,20 beta-diOH-P showed a clear peak in each breeding season. In Group IV, milt was expelled from December to July, and plasma steroid levels remained high until June before declining to the basal levels; however, these fish failed to mature in the ensuing winter breeding season. Plasma GtH levels in Groups III and IV were significantly higher than those in Groups I and II in the summer breeding season. These results clearly indicate that fish in Group III are twice-annual spawners.

Animals↗
PubMed1986

Gonadotropin surge during spawning in male goldfish.

Changes in plasma hormone levels during spawning were studied in male goldfish. Blood samples were analyzed for gonadotropin (GtH), testosterone, 11-ketotestosterone (11-KT), and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOH-P) in males, and for GtH in females. Spawning was induced by raising water temperature from 12 to 20 degrees in sexually mature goldfish kept in pairs. Plasma GtH levels in males showed a marked increase (GtH surge) which was synchronous with the preovulatory surge in females, and peaked at the onset of spawning. Plasma levels of testosterone and 17 alpha, 20 beta-diOH-P increased almost at the same time as the GtH surge in males, whereas 11-KT levels remained low during the spawning. The small increase in GtH in males could be induced in the absence of females by raising the water temperature, but the levels were significantly enhanced by the presence of ovulatory females. A large amount of milt was observed during spawning, and the amount was correlated with plasma levels of GtH. Increased levels of GtH may be involved in milt production. We can propose that the synchronous GtH surge in both sexes causes ovulation and milt production to occur at the same time, favoring a higher rate of fertilization of the eggs.

Animals↗