Biomedical subjects

H Nigi

Publications and source records attributed to H Nigi.

33 records · Page 2Linked to original sources

PubMed1993

[Effects of repeated restraint stress at 30-minute intervals during 24-hour on serum testosterone, LH and glucocorticoids levels in male Japanese monkeys (Macaca fuscata)].

We investigated effects of frequent blood collections under the compulsory restraints on serum testosterone, LH and glucocorticoids in adult male Japanese monkeys. Blood samples were withdrawn from three animals at 30-min intervals and two animals at 4-hr intervals during 24 hr. Serum testosterone and LH were measured by a radioimmunoassay, and glucocorticoids was determined by a competitive protein binding assay. Sampling at 4-hr intervals during 24 hr revealed diurnal changes in serum testosterone and glucocorticoids. Levels of testosterone were high throughout the night and low at the day time, conversely serum glucocorticoids were high levels in the morning and low in the evening. On the other hand, 30-min intervals sampling, serum testosterone levels decreased and glucocorticoids levels increased, respectively, immediately after the start of blood sampling. And then, low in testosterone and high in glucocorticoids levels were continually maintained. But serum LH levels had the pulsatile pattern and did not change markedly during 24 hr. After ACTH administration in five animals, serum glucocorticoids levels increased markedly and also testosterone levels increased slightly, but LH levels did not change. These data indicated that the every 30-min restraint stress caused the increment of glucocorticoids levels and the suppression of testosterone levels, but did not affect the serum LH levels. The increased glucocorticoids might inhibit the testicular steroidogenesis, without suppressing the LH secretion from the pituitary.

Animals↗

PubMed1993

[Hypothalamo-pituitary-ovarian function in female Japanese monkeys (Macaca fuscata) in the non-mating season].

We investigated the mechanism of reduction of hypothalamo-pituitary-ovarian function in female Japanese monkeys in the non-mating season. We administered PMSG and LH-RH to 19 females in the non-mating and in the mating season. When PMSG was administered every day for 12 to 14 days to seven monkeys in the non-mating season, follicle development was observed together with an increase in serum estradiol-17 beta (E2), but there was no rise in serum LH in two animals and little increase in five others. Follicle involution began about ten days after PMSG administration, and no ovulation occurred. These findings show that secretion of LH by the pituitary in response to positive feedback by the E2 secreted by the follicles which had developed was in adequate to induce ovulation. Serum LH levels increased markedly in five females after a single iv injection of LH-RH in the mating season, but not at all in the non-mating season, even when five-times the dose was administered. These data show that the LH-secreting function of the pituitary is definitely reduced in the non-mating season. When LH-RH was administered to seven monkeys following PMSG administration, an LH surge was observed in all animals, and ovulation occurred in four animals. These findings suggest that one reason for the reduction in pituitary-ovarian function in the non-mating season was a decline in LH-RH secretion by the hypothalamus.

Animals↗

PubMed1992

Annual changes of testis size, seminiferous tubules and plasma testosterone concentration of wild Sika deer (Cervus nippon yesoensis Heude, 1884) in Hokkaido.

Testis size, seminiferous tubules and plasma testosterone concentrations showed conspicuous annual changes in Sika deer of Hokkaido, Japan. The onset of the spermatogenic process occurred in July or August. Spermatogenic activity had already reached its height in late October, at the beginning of the rutting season, and had begun to decline in late December. Spermatogenesis had stopped in February or March. Plasma testosterone concentrations showed very high levels in late October and early November, but was almost at the basal level in February, March, June and December. The wide individual variation of the plasma levels in October suggest pulsatile secretions of testosterone.

Animals↗

PubMed1992

[The artificial fecundation in Japanese monkeys (Macaca fuscata) by induced ovulation and artificial insemination in nonmating season].

Induced ovulation trials by PMSG-hCG administration were conducted in eleven female Japanese monkeys showing neither bleeding nor ovulation in nonmating season. The ovulation was confirmed by the laparoscopic observation in nine of the 11 females. Artificial inseminations were performed in these 9 females by the injection of semen collected by the penile electrode approach. The semen was injected into the uterine cervix in 6 females or the uterine cavity in 3 females. A gestational sac was confirmed on the ultrasonic diagnostic apparatus 19 days after ovulation in one of the 3 females inseminated into the uterine cavity. The pregnancy, however, could not be maintained.

Animals↗

PubMed1992

Measurement of serum IgE antibodies against Japanese cedar pollen (Cryptomeria japonica) in Japanese monkeys (Macaca fuscata) with pollinosis.

IgE antibodies against allergens of Japanese cedar (Cryptomeria japonica, CJ) pollen in the serum of seven Japanese monkeys (Macaca fuscata) with pollinosis were measured by fluorometric indirect enzyme-linked immunosorbent assay (ELISA). All of the monkeys were found to have specific IgE to the crude pollen antigen. The specific IgE levels were well correlated with those determined by the Pharmacia CAP system. IgE antibodies were then assayed with two kinds of purified allergens (Cry j I and Cry j II) by the ELISA. We found that five monkeys had specific IgE to both allergens, although the other two had IgE only to Cry j I or Cry j II; there is different immune responsiveness to the two major allergens in the monkeys.

Allergens↗

PubMed1991

[Periovulatory time courses of serum LH in the Japanese monkey (Macaca fuscata)].

Serum LH, E2-17 beta and progesterone concentration were measured in 16 cycles of 15 female Japanese monkeys. Three of the 16 cycles were ascertained to be anovulatory. Ten of the 13 ovulatory cycles showed LH peaks varying from 25 to 280 ng/ml. However, in remaining 3 cycles, LH peak could not be determined, probably because of a lag of blood-sampling schedule. E2-17 beta peaks were detected 0-30 hrs before LH peak in 8 cycles, but 13 or 20 hrs after LH peak in 2 cycles. Time-intervals from LH peak to ovulation ranged 0-47 hrs 30 min. No correlation was detected between concentrations of LH and progesterone in the luteal phase.

Animals↗

PubMed1983