Biomedical subjects

T Kurohata

Publications and source records attributed to T Kurohata.

5 recordsLinked to original sources

PubMed1998

Effect of the nitric oxide level in the medial preoptic area on male copulatory behavior in rats.

We investigated the influence of the extracellular nitric oxide (NO) level on male copulatory behavior. We confirmed the changes of nitrite (NO2-) and nitrate (NO3-) in the medial preoptic area (MPOA) by administration of the NO precursor L-arginine (L-Arg, 10 mM) or the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA, 10 mM) via a dialysis probe. NO2- and NO3- were measured simultaneously by an in vivo microdialysis method coupled with the Griess reaction. L-Arg induced significant elevations of extracellular NO2- and NO3-. L-NMMA significantly reduced NO2- and NO3- levels. We observed male copulatory behavior during infusion of L-Arg or L-NMMA. The mount rate of male rats significantly increased during infusion of L-Arg in the MPOA. Administration of L-NMMA reduced the mount rate. These findings suggested that the elevation of extracellular NO in the MPOA facilitates male copulatory behavior of rats, whereas the decrease of NO reduces their copulatory behavior.

Animals↗

PubMed1995

[The preventive effect of indeloxazine hydrochloride to the sexual dysfunction caused by anti-androgenergic agent (allylestrenol)].

Anti-androgenergic agents are usually used for patients with benign prostatic hypertrophy (BPH). However steroidal anti-androgenergic agents tend to suppress the sexual function. This side effect is very significant in middle-aged men. Therefore we studied the preventive effect of indeloxazine hydrochloride (INDX), which induces an increase of the dopamine level in the brain, on the sexual dysfunction induced by an anti-androgenergic agent (allylestrenol: ALE). Thirty-six patients with BPH were classified into two groups, one used ALE only, and the other ALE with INDX. For the subjective evaluation of the sexual function, a self assessment questionnaire method was employed before and after administration. We especially studied 3 questions, "morning erection", "erectile capacity" and "frequency of sex". For the objective evaluation of the sexual function, nocturnal penile tumescence (NPT) was measured using an erectometer. NPT occurs in healthy males as a physiological phenomenon and it shows the erectile capacity objectively. The levels of LH, total testosterone and free testosterone were also determined. In the ALE only group, sexual dysfunction was found subjectively and objectively, but in the ALE with INDX group, it was not found. Levels of LH, total testosterone and free testosterone were decreased in the both groups. There was no significant difference between the two groups. We hypothesized that the sexual dysfunction due to ALE is related with not only to the decrease of androgen, but also to suppression of the central nervous system; for example, the suppression of the area of the brain mediating sexual behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

[Changes in the salivary testosterone level in aged].

Measurement of the level of free testosterone is important in the evaluation of testicular function. Because most of the testosterone in the saliva is in the free form, measurement of the salivary testosterone level is considered to be effective for the evaluation of testicular function. In the present study, a commercial kit was employed to measure the salivary testosterone level, and the change in the salivary testosterone level with age was investigated. The subjects of this study were 76 males, 20-89 years of age, with no endocrinological diseases. The concentration of testosterone in the saliva was measured for each of the subjects, and for 34 of the subjects the concentrations of total testosterone and free testosterone in the serum were also measured at the same time. Standard serum was diluted to have a testosterone concentration of 50 pg/ml, and the results indicated that it was sufficiently possible to measure the salivary testosterone. The coefficient of correlation between the salivary testosterone concentration and the serum total testosterone concentration was 0.479 (p < 0.01), while the coefficient of correlation between the salivary testosterone concentration and the serum free testosterone concentration was 0.732 (p < 0.001). These findings thus indicate that the correlation between the salivary testosterone concentration and the serum free testosterone concentration is better than that between the salivary testosterone concentration and the serum total testosterone concentration. It was also demonstrated that the salivary testosterone concentration decreased significantly with aging after the fifth decade of life. The correlation coefficient for that relationship was -0.606 (p < 0.001), and the change was similar to that seen in the serum free testosterone concentration as a function of aging. The findings suggested that measurement of the salivary testosterone concentration with the commercial kit is useful for the evaluation of testicular function.

Adult↗

PubMed1990

[Determination of the normal range of serum LH and FSH levels in normal adult males--comparison with IRMA and RIA].

To determine the normal range of serum LH and FSH levels, blood samples from 53 normal adult males were measured by a double antibody radioimmunoassay system and a new immunoradiometric assay (IRMA) system. It was necessary to evaluate the individual pulsatile secretion and the differences in measured values among laboratories to determine the normal range. Therefore, in 53 normal adult males lacking any evidence of hormonal abnormalities, blood was sampled at 9:00 a.m. daily for 3 days, and these samples were measured in 3 laboratories. The result of the hormone concentration of blood sample was not appropriate as the normal range because of the high amplitude of LH and FSH pulses. Coefficient values (CV) between the mean value of the first two samples and the mean value of all three samples were small. Therefore, the mean value of the first two samples was clinically accurate for use as the normal range. Significant differences in measured values were observed among the 3 laboratories. The normal range, which included individual pulsatile secretion, and the differences in measured values among the laboratories was as followings: LH (RIA): 7.6-13.7 mIU/ml, LH (IRMA): 2.1-4.7 mIU/ml, FSH (RIA): 4.7-9.5 mIU/ml, FSH (IRMA): 3.0-7.4 mIU/ml. The serum LH and FSH levels of 68 untreated male infertility patients tended to rate high with respect to our normal range. It was considered that the normal range determined in this study was useful for clinical management.

Adult↗

PubMed1988

Human chorionic gonadotropin beta-subunit in human semen.

The level of human seminal chorionic gonadotropin beta-subunit (hCG beta) was determined by radioimmunoassay (RIA). The mean hCG beta level in 34 normal men was 3.7 +/- 1.6 ng/ml, which was much higher than that in serum. The mean hCG beta level for 20 patients with mild oligozoospermia (20-39 x 10(6) sperm/ml) was 2.5 +/- 0.8 ng/ml, that for 34 patients with severe oligozoospermia (1-19 x 10(6) sperm/ml) was 1.7 +/- 0.5 ng/ml, and that for 21 azoospermia was 1.5 +/- 0.6 ng/ml. Thus, the decrease of sperm count was correlated with the decrease of hCG beta. In 17 cases to which testicular biopsy was applied together with sperm counting, the seminal hCG beta level was found to positively correlate with the germinal cell index (the ratio germinal cell count/Sertoli cell count) and with the testicular volume. The level of seminal hCG beta was also found to correlate negatively with the levels of seminal LH and FSH and positively with the level of seminal testosterone. These findings suggest that the production of seminal hCG beta is a process of spermatogenesis and closely related to spermatogenesis. The level of hCG beta in serum was too low to detect, and no relation to that in seminal plasma could be investigated. However, in 6 cases with testicular tumor, the hCG beta level in serum was high, whereas that in seminal plasma was rather low probably because of unilateral secretion. Enhanced production of hCG beta by tumor tissues and the destruction of the blood-testis barrier by proliferation of tumor cells seemed to be one of the causes of this high hCG beta level in serum. The hCG beta levels in 13 vasectomized seminal plasma and the prostatic fluid samples collected from 3 normal men were 1.5 ng/ml, which was similar to those in azoospermic patients. These findings suggest that the seminal hCG beta level consists of the hCG beta secreted by the testis and about 1.5 ng/ml of hCG beta from the prostate. Based on these results, seminal hCG beta is thought to be secreted by the prostate and the process of spermatogenesis and the value of seminal hCG beta may serve as an effective index for the testicular function.

Adult↗