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Biomedical subjects

R Demura

Publications and source records attributed to R Demura.

At least 73 records · Page 4Linked to original sources
PubMed1987

Short term treatments with prolactin, HMG or testosterone fail to affect testicular inhibin content in rats.

To investigate the effect of prolactin (PRL) on testicular function, especially on spermatogenesis, testicular inhibin content in male rats treated with PRL was compared with those treated with HMG and testosterone. Mature Wistar male rats were given 10 or 50 IU of ovine PRL, 10 IU of HMG and 5 mg of testosterone, i. m. for 5 consecutive days and testes were removed for assessing inhibin content. Inhibin content was measured by a FSH suppressing activity in cultured rat anterior pituitary cells using aquous extract of testes. Five days' treatment with PRL, HMG, or testosterone did not influence testicular inhibin content in male rats. The possibility that these treatments had transiently affected testicular inhibin content, or that inhibin content did not reflect inhibin production was not ruled out.

Animals↗
PubMed1987

Effect of uni- and bilateral cryptorchidism on testicular inhibin and testosterone secretion in rats.

The effect of uni- and bilateral cryptorchidism on testicular inhibin and testosterone secretion and their relationships to gonadotropins were studied in rats. Mature Wistar male rats weighing approximately 300 g were made either uni- or bilaterally cryptorchid. Testicular inhibin and testosterone content and plasma levels of LH and FSH were examined 2 weeks later. A similar remarkable decrease in testicular inhibin content was found in uni- and bilaterally cryptorchid testes. On the other hand, the testicular testosterone content was significantly decreased only in unilaterally cryptorchid testis with an inverse increase in the contralateral testis. Plasma testosterone levels were normal and plasma LH and FSH increased significantly in both of the cryptorchid groups. These results showed that cryptorchidism impairs both Sertoli and Leydig cell functions. While testosterone production was compensated by increased LH for 2 weeks, neither inhibin secretion nor storage changed in cryptorchid or contralateral testes during the same period.

Animals↗
PubMed1987

[A clinical evaluation of CA 125 levels in serum, ascites and pleural effusion].

CA 125 in serum, ascites and pleural effusion has been measured in various diseases by an immunoradiometric assay using ELISA CA 125 Kit for an evaluation of its clinical significance as a possible tumor marker. Serum CA 125 was found to be elevated in 90% of the cases involving ovarian cancer and especially in cases of serous cystadenocarcinoma in the early stages, though these serum levels decreased after effective treatment. The CA 125 also was elevated in 63% of the cases involving lung cancer, mostly in the advanced cases regardless of the histological type. CA 125 in ascites proved to be only elevated in malignant diseases, but it was equally high in pleural effusions both in benign and malignant diseases.

Antigens, Neoplasm↗
PubMed1986

Renin in the rat pituitary coexists with angiotensin II and depends on testosterone.

In the rat pituitary gland, immunoreactive angiotensin II (ANG II), renin, and LH, but not PRL, were found within the same cells of the anterior pituitary gland by staining with the avidin-biotin complex method in adjacent sections. No renin-positive staining was observed in the pituitary of the rats after 10 days of castration, but positive staining reappeared after 8 weeks. This effect of castration on renin immunoreactivity was abolished by the simultaneous administration of testosterone. In contrast, ANG II immunoreactivity was unaffected by castration. The intensity of renin immunoreactivity in the pituitary was less prominent in the female than in the male rat. These results suggest that there exists a pituitary renin-angiotensin system localized in the gonadotrophs and that the pituitary renin is under androgenic control.

Angiotensin II↗
PubMed1986

The significance of alpha-subunit as a tumor marker for gonadotropin-producing pituitary adenomas.

We studied gonadotropin hormone alpha-subunit and gonadotropin secretion in four patients with gonadotropin-producing pituitary adenomas. All four patients had elevated plasma alpha-subunit levels, ranging from 2.8-8.5 ng/ml (normal, less than 0.5 ng/ml). alpha-Subunit responses to LHRH were less than those in seven patients with primary gonadal failure. The relative proportions of the gonadotropin and alpha-subunit peaks in one patient were the same before and after LHRH administration, based on gel filtration studies of plasma. The alpha-subunit levels decreased little during testosterone treatment in the two adenoma patients so treated. Immunohistochemical study of the adenomas from two patients demonstrated definite staining with alpha-subunit and gonadotropin antisera. Elevated plasma levels of alpha-subunit and its relative unresponsiveness to LHRH stimulation or testosterone suppression suggest that the alpha-subunit originated in tumor tissue and that its measurement is useful for the diagnosis of a gonadotropin-producing tumor in patients with elevated plasma levels of LH and/or FSH.

Adenoma↗
PubMed1986

Prolactin interacts with gonadotropin through a suppression of c-AMP production probably as a LH-sensitive adenylate cyclase inhibitor.

The interaction between gonadotropin and prolactin (PRL) on ovarian steroidogenesis as well as c-AMP production was studied in rat ovaries. Ovaries obtained from adult female Wistar rats in a morning of proestrus were chopped into 30-40 pieces and subjected to short term incubation studies using various buffers. HCG-stimulated c-AMP, estradiol (E2), progesterone (P) secretions were suppressed in a dose-dependent manner by ovine (o) PRL in a plain Gey-Gey (G-G) buffer. Addition of 3-isobutyl-1-methyl-xanthine (IBMX) increased c-AMP accumulation as well as E2 and P secretions. Deletion of Ca++ from the IBMX buffer stimulated c-AMP production, but suppressed steroid secretion. The inhibitory effect of PRL on E2 and P was not demonstrated in IBMX buffer at any Ca++ concentration examined despite suppression of c-AMP production. In conclusion, it was demonstrated that PRL inhibited gonadotropin-stimulated production of E2 and P by inhibiting c-AMP production. IBMX stimulated accumulation of c-AMP, E2 and P and counteracted with the antigonadal effect of PRL. Ca++ inhibited c-AMP accumulation but stimulated E2 and P secretions. The data suggested that PRL exerts its antigonadal effect through an inhibition of adenylate cyclase action in a manner similar to that of Ca++.

1-Methyl-3-isobutylxanthine↗
PubMed1985

Steroid receptors in dimethylhydrazine-induced colon carcinogenesis.

To investigate whether gonadal hormones are involved in the tumorigenesis of dimethylhydrazine (DMH)-induced colonic neoplasms, the authors measured steroid receptors in the neoplasms. 30- or 60-day-old BD-IX rats were injected with 20 mg of 1,2-DMH per kg of body weight once a week for 20 weeks. Fifty-seven rats were sacrificed at 40 to 45 weeks after the initial injection. Androgen receptor (AR), estrogen receptor (ER), and progesterone receptor (PR) were measured in colonic neoplasms. The total number of colonic neoplasms was 274 among 57 rats, 65.8% in male rats and 34.2% in female rats. The mean number of colonic neoplasms per rat was higher in male rats, i.e., 5.6, compared with 3.5 in female rats. A slightly higher number of colonic neoplasms per rat was seen in the rats that had the initial injection at 30 days of age. The number of large colonic neoplasms with a diameter of more than 1 cm was 77 (28.1%), 74% of which were seen in male rats. Thus, a higher incidence of tumors that were also larger were seen in male rats. Histologic findings showed that 53.6% of the neoplasms were carcinomas. The highest incidence of colonic neoplasms was in the distal colon in both sexes. Most of the well-differentiated adenocarcinoma were seen in the distal colon (82.2%), whereas mucinous carcinoma and undifferentiated adenocarcinoma were prominent in the proximal colon or cecum (56.1%). In rats with a normal colon, low levels of AR and PR were determined; but ER was not found in any regions of the colon. In DMH-induced colonic cancer, the incidence as well as the concentration was higher in male rats (60.6%, 16.9 +/- 3.6 fm/mg protein), compared with female rats (40.0%, 4.6 +/- 0.8 fm/mg protein). Similar incidences and levels of ER and PR were seen in both sexes. There was no relationship between steroid receptors and histologic findings in colonic neoplasms. These results suggest that the gonadal hormones, especially androgens, appear to be involved in DMH-induced colon tumorigenesis in male rats.

1,2-Dimethylhydrazine↗
PubMed1985

Changes in computed tomographic findings in microprolactinomas before and after bromocriptine.

Computed tomography (CT) of the pituitary before and after bromocriptine treatment were performed in 10 patients with microprolactinoma. Intrapituitary low densities were demonstrated in 7 out of the 10 patients before bromocriptine. Low densities shrank in size and increased in density after normalization of the plasma prolactin (Prl) level following bromocriptine. At the same time, various degrees of empty sella were demonstrated in these patients and in 2 out of the 3 without noticeable changes before treatment. It was concluded that enhanced CT scans, especially sagittal reconstruction images, were very informative for the diagnosis of microprolactinoma and that bromocriptine reduced the size of the microprolactinoma and often led to empty sella.

Adult↗
PubMed1985

[Tumor markers in testicular tumors].

Serum levels of hCG, AFP, CEA and testosterone were measured in 20 patients with testicular tumors for an evaluation of their clinical significance as tumor markers. HCG was elevated in those with chorional and syncytiotrophoblastic cell tumors, but it was also detected in some cases of embryonal carcinoma and seminoma, suggesting the presence of hCG-producing elements. AFP was exclusively elevated in embryonal and yolk sac tumors. CEA and testosterone were mostly normal in all patients. HCG and AFP fluctuated in good correlation with the clinical course. Thus, hCG and AFP were valuable tumor markers for testicular tumors for the diagnosis of histological type and stage and monitoring the therapeutic effect and prognosis.

Adult↗
PubMed1984

Steroid receptors and the distribution of IR-carcinoembryonic antigen in colonic cancer.

Twenty-five colonic cancer tissues were studied for the presence of estrogen and progesterone receptors (ER, PR) and the distribution of immunoreactive carcinoembryonic antigen (IR-CEA). ER and PR were determined in 6 (24 per cent) and 3 (12 per cent), respectively, of 25 patients with colonic cancer. Of the six patients with ER, five were females, four of whom were postmenopausal. Steroid receptors, however, had no correlation with age, tumor localization, stage of disease or IR-CEA. In cancer tissue, IR-CEA in the cytosol fraction was higher than that found in the membrane fraction. In normal colon, however, the concentrations of the two fractions were reversed. Immunohistochemical findings have shown a different distribution of IR-CEA in cancerous and normal colon, and our results demonstrated similar findings by using radioimmunoassay (RIA).

Adult↗
PubMed1984

Restoration of fertility with gonadotropin and bromocriptine in a hypogonadal man after removal of macroprolactinoma.

A case of male hypogonadism after removal of macroprolactinoma was successfully treated with gonadotropin. A 35-year-old man treated surgically for pituitary adenoma had elevated plasma prolactin and impaired pituitary function after the operation. He was on replacement of hydrocortisone, levothyroxine and testosterone depot along with bromocriptine. Normal plasma testosterone levels were achieved with HCG, 3,000 IU three times a week. The addition of 75 IU of FSH daily restored spermatogenesis and the sperm count reached the fertile range at the 11th month. Doses of HCG and FSH were cut in half at the 10th month without affecting the plasma testosterone levels. His wife was impregnated at the 12th month and gave birth to a normal baby girl.

Adult↗