Biomedical subjects

N Mikuma

Publications and source records attributed to N Mikuma.

24 records · Page 2Linked to original sources

PubMed1990

[Therapeutic evaluation of male infertility--the increase of seminal transferrin level and the improvement in sperm concentration following administration of clomiphene citrate].

This study was designed to evaluate the functional changes of Sertoli cells following the administration of clomiphene citrate for male infertility. Sperm count and seminal transferrin level were measured before and after the treatment in 22 cases of oligozoospermia (sperm count: less than 20 X 10(6)/ml) and 14 cases of subnormal sperm count group (sperm count: 20-30 X 10(6)/ml). Clomiphene citrate was administered per os for more than 3 months consecutively in a dose of 25 mg/day. Seminal transferrin concentration increased more than 1.5 times compared with pre-treatment level in 6 cases (16.7%). Among these patients, sperm count markedly increased (20 X 10(6)/ml or more than the pre-treatment level) in 3 cases (50%) and slightly increased (10 X 10(6)/ml or more than pre-treatment) in 1 case (16.7%). In 30 cases, in which seminal transferrin level did not increase, sperm count markedly increased in 6 cases (20%) and slightly increased in 6 cases (20%). Thus, sperm count was improved more frequently in the cases in which seminal transferrin level remained elevated than the cases with no elevation of serum transferrin level. Serum FSH level of patients whose seminal transferrin level remained elevated after the treatment was significantly higher than that of patients with no elevation of serum transferrin level (mean +/- SD = 32.8 +/- 18.0 mIU/ml v.s. 14.4 +/- 11.7 mIU/ml, respectively). These data suggested that the activation of Sertoli cells may contribute to the increase of sperm count following the administration of clomiphene citrate and the elevated seminal transferrin secretion may be related to the increase of serum FSH level following this treatment.

Clomiphene↗

PubMed1990

[Mass screening of prostate in Shiribeshi area in Hokkaido--incidence and clinical symptoms of benign prostatic hypertrophy and prostatic carcinoma].

A prostate mass screening was performed in 6 towns in Shiribeshi area in Hokkaido Prefecture on 384 males who were over 50 years old. The screening included digital palpation, uroflowmetry, blood sampling for tumor markers, questionnaire for voiding disturbances and transrectal sonography. Prostatic carcinoma was found in 9 (2.3%) of 384 males. An incidence of benign prostatic hypertrophy was 15.6% in 384 males. Atypical hyperplasia was found in 4 among 35 biopsied cases. Incidence of voiding disturbance such as retardation, prolongation and nocturia significantly increased with age as well as prostate size.

Aged↗

PubMed1989

Effect of kallikrein on the Sertoli cell function.

The effect of kallikrein on the Sertoli cells was investigated to determine the rat testicular androgen binding component (ABC = androgen binding protein + androgen receptor) concentration using the dextran-coated charcoal method. The results showed that the concentrations of testicular ABC were increased significantly by the administration of kallikrein to levels approaching those seen after stimulation by LH-RH or FSH. Therefore, it is suggested that kallikrein has an effect that influences the Sertoli cells directly or indirectly.

Androgen-Binding Protein↗

PubMed1989

[A clinical study of congenital adrenal hyperplasia].

We have compared three treatments of congenital adrenal hyperplasia (CAH) for their effect on physical development. Thirteen girls and two boys with CAH due to 21-hydroxylase deficiency were treated with three different treatments, hydrocortisone (HC), dexamethasone (DXM) and cyproterone acetate (CA). The results showed that height growth was better with HC and CA than DXM, and bone excessive maturation was more suppressed with DXM and CA than HC. A dose-dependent relationship was revealed between body weight and dose of HC. Iatrogenic obesity was found in 42.9% and 38.1% of the patients treated with DXM and HC, but none of the patients treated with CA did became obese. Physical growth was better with CA treatment than HC or DXM treatment, but CA may have a suppressive effect on the pituitary-adrenal axis observed carefully, especially on prepubertal and pubertal cases.

Adrenal Hyperplasia, Congenital↗

PubMedDate not supplied

Role of the hypothalamic opioidergic system in the control of gonadotropin secretion in elderly men.

The role of opioidergic system in controlling gonadotropin secretion in elderly men still remains uncertain. In the present study, we attempted to examine the opioidergic inhibitory tone imposed on GnRH release mechanism in elderly men by monitoring the plasma gonadotropin response to the opiate receptor antagonist naloxone hydrochloride. Six normal young men and 10 elderly men with no endocrinological diseases volunteered for the present study. In young men, plasma LH showed a biphasic increase in response to naloxone and plasma LH level during naloxone treatment was significantly higher than the mean of prenaloxone control levels. In contrast, plasma LH in elderly men was not affected by naloxone. The ratio of the peak plasma LH response during naloxone treatment to the mean pre treatment LH level (plasma peak/basal LH ratio) declined with the advance of age (r = -0.74, P < 0.005) and also correlated significantly with plasma free testosterone level (r = 0.45, P < 0.05). These data suggest (1) that the hypothalamic opioidergic tone is reduced in elderly men and (2) that the primary testicular insufficiency with the advance of age may play a major role in the decline of the hypothalamic opioidergic tone in elderly men.

Adolescent↗

PubMedDate not supplied

Restoration of testicular transferrin, insulin-like growth factor-1 (IGF-1), and spermatogenesis by exogenously administered purified FSH and testosterone in medically hypophysectomized rats.

To investigate the relation between testicular transferrin and insulin-like growth factor-1 (IGF-1) secreted by Sertoli cells and the differentiation of germ cells in the rat, testosterone and/or purified FSH was administered to rats medically hypophysectomized by an LH-RH agonist. Spermatogenesis was quantitatively analyzed and concentrations of intratesticular transferrin and IGF-1 were measured by radioimmunoassays. The last step of spermatogenesis was quantitatively restored by combined administration of testosterone and purified FSH. Intratesticular IGF-1 concentrations were significantly increased by combined administration of testosterone and purified FSH. From these observations, it is surmised that IGF-1 may have a stimulatory effect on the last step of spermatogenesis.

Animals↗