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Biomedical subjects

R Demura

Publications and source records attributed to R Demura.

At least 127 records · Page 7Linked to original sources
PubMed1978

Effect of CB-154 therapy on the glucose tolerance, IRI and GH response to glucose administration in acromegaly.

Effects of CB-154 therapy on the glucose tolerance, IRI and GH responses to the oral glucose administration in 5 acromegalic patients with impaired glucose tolerance were examined. Glucose tolerance improved in all patients with a reduction in GH levels. Insulin secretion in response to the oral glucose administration was exaggerated in 3 patients, while it was supressed in 2 patients who had severely impaired glucose tolerance. After receiving CB-154 therapy, hyperresponsiveness of insulin observed in the 3 patients and a suppressed response in one patient were corrected to normal, while a low response in another stayed unchanged. This observation suggest that variable abnormalities in insulin secretion induced by the excess of GH improve with a decrease in plasma GH levels. However, the abnormal GH secretion in response to hyperglycemia persisted still after administration of CB-154 in spite of decreased basal plasma GH levels.

Acromegaly↗
PubMed1978

Plasma TSH and prolactin response to insulin induced hypoglycemia in patients with hypothalamic pituitary disorders.

Plasma TSH and prolactin (PRL) responses to insulin-induced hypoglycemia (ITT) were examined in 37 patients with various hypothalamic pituitary disorders. Four patients showed a definite TSH response to ITT. They were 2 patients with suspected pinealoma with diabetes insipidus (DI), a patient with pituitary adenoma and a patient with acute prophyria. A suspected hypothalamic dysfunction and a slightly impaired pituitary function manifested as GH deficiency were their common endocrinological features. On the contrary, plasma PRL response to ITT was noted in about one third of the patients examined, but no concomitant PRL response was observed in any of the patients with a definite TSH response. This suggested a different mechanism of TSH and PRL secretion may be different under this circumstance and a certain factor related to the hypothalamic disorder may play a modulating role in an unusual TSH response to hypoglycemia in these particular patients.

Adolescent↗
PubMed1977

Corticotropin-releasing factor-like activity in ACTH producing tumors.

Corticotropin-releasing factor (CRF)-like activity in two different kinds of ACTH-producing tumors (human ectopic ACTH-producing colonic cancer and rat MtT/F4 tumor) was determined by an in vitro method using isolated normal rat pituitary cells. The ACTH content of the post mortem colonic cancer was 5.5 ng/g w.wt. The ACTH content of the medium of MtT/F4 tumor cells was 153+/-32 pg/10(5) cells. The ACTH content of MtT/F4 tumor cell suspensions was elevated with increasing doses of hypothalamic median eminence extract (HME). The response of MtT/F4 tumor cells to HME was suppressed by 1 mug/ml of dexamethasone. Extracts of colonic cancer, MtT/F4 tumor and HME produced elevation of the ACTH content of the medium of isolated rat pituitary cells. The CRF-like activities of two kinds of tumor extracts in multiple dilutions ran parallel to that of HME. The CRF-like activities were 0.037 HME equiv/mg w.wt in MtT/F4 tumor and 0.052 HME equiv/mg w.wt. in colonic cancer. These results demonstrated that CRF-like activity existed in these two kinds of ACTH-producing tumors.

Adrenocorticotropic Hormone↗
PubMed1977

FSH and LH secreting pituitary adenoma.

A case of FSH and LH secreting pituitary adenoma which was not preceded by hypogonadism is reported. The patient, a 50-year-old man, was admitted to the hospital because of left temporal hemianopsia. No clinical evidence of hypogonadism was demonstrated. Endocrine studies of hypogonadism was demonstrated. Endocrine studies revealed markedly elevated plasma FSH of 295 mIU/ml and slightly elevated LH of 35 mIU/ml (2nd IRP-HMG). Plasma FSH and LH did not respond to the administration of LRF, conjugated equine estrogens and testosterone. Plasma testosterone was 691 ng/dl and rose nromally after pregnant mare's serum gonadotropin. Sperm count was 46 X 10(6)/ml. Transfrontal hypophysectomy was followed by a marked decrease of both FSH (to 19mIU/ml) and LH (to 22 mIU/ml). Histologic examination of the tumor revealed 90% chromophobe cells and 10% slightly eosinophilic cells. Two sizes of secretory granules were demonstrated. Tumor cells in tissue culture secreted both FSH and LH.

Adenoma↗
PubMed1977

Growth hormone and prolactin in tissue culture of pituitary adenoma.

Pituitary adenomas obtained from 6 patients with acromegaly and 8 patients with chromophobe adenoma were subjected to the tissue culture to correlate in vitro secretion of growth hormone (GH) and prolactin (PRL) to preoperative in vivo endocrine studies and endocrinilogical manifestations. Tissue culture demonstrated that all of the acromegalic tumors secreted large amounts of GH for 2-4 weeks and some of the PRL-secreting chromophobe adenoma without any clinical and endocrinological evidences of GH secretion secreted considerable amounts of GH; however, no recognizable GH secretion was noted in the remaining chromophobe adenomas. PRL was secreted in vitro in large amounts by tumors obtained from patients with hyperprolactinemia with and without acromegaly. It is interesting to note that tumors obtained from 2 patients who showed very slight elevation of plasma PRL of less than 40 ng/ml secreted large amounts of PRL in vitro. This finding suggests that PRL-secreting adenoma could not be ruled out in patients with mild hyperprolactinemia. The duration of in vitro PRL release was longer than that of GH and its rate of decrease was slower than that of GH.

Acromegaly↗
PubMed1977

Stimulation of immunoreactive somatostatin release from hypothalamic synaptosomes by high (K+) and dopamine.

Effects of high (K+) and dopamine on the release of immunoreactive somatostatin from isolated hypothalamic synaptosomes were studied in rats. High (K+) (60 mM) and dopamine (10(-6) M) in the incubation media stimulated the release of immunoreactive somatostatin and the former effect was completely abolished by the removal of Ca++ from the media. These suggest that hypothalamic somatostatinergic synaptosomes preserved at least one of the important basic properties of secretory cells. Although it is of interest to note that dopamine stimulated the release of somatostatin. Its physiological significance awaits further studies.

Animals↗
PubMed1977

Human chorionic gonadotropin produced by ectopic pinealoma in a girl with precocious puberty. Case report.

A case is reported in which a human chorionic gonadotropin (HCG-)-producing ectopic pinealoma was found in a 5-year-old girl with precocious puberty. Physical examination revealed abnormal breast enlargement. Endocrinological study disclosed a high plasma HCG concentration of 1192 ng/ml with a normal follicular stimulating hormone (FSH) level. The HCG content of the tumor was as high as 400 ng/mg of acetone dried tissue, but no FSH was detectable. This is the first reported case of precocious puberty associated with pineal tumor in a female.

Cerebral Ventricle Neoplasms↗
PubMed1977

[Growth hormone, prolactin, LH and FSH secretion in tissue culture of pituitary adenomas (author's transl)].

We have performed tissue culture of pituitary adenomas (5 acromegalies, 7 non-acromegalies) and measured GH, PRL, LH and FSH in the media of tissue culture by radioimmunoassay (RIA) for 30-40 days. In addition, GH, PRL, LH and FSH were measured in the plasma and tumor tissue by RIA. GH concentration in the culture media was markedly high in all cases with acromegaly and high also in 2 out of 7 non-acromegaly cases (case 6 and 7). GH concentration in the media rapidly decreased almost as a straight line on a semilogarithmic scale until the 30-40 in day, when GH level became less than 10 ng/ml. PRL concentration in the culture media was high in 5 patients (3 acromegalies, 2 non-acromegalies). PRL concentration regressed more slowly than GH, but still remained higher than 10 ng/ml in all of the patients on the 25-40th day when the studies were discontinued. LH and FSH concentrations in the culture media was high in two patients. One patient was a pituitary adenoma secreting LH and FSH, and another case was a false high secreting one, possibly contaminated with gonadotropin in normal pituitary gland at surgical operation. LH and FSH concentrations rapidly decreased as that of GH. A rare case of primary LH and FSH secreting pituitary adenoma was demonstrated.

Acromegaly↗
PubMed1976

A female case of the HCG-producing ectopic pinealoma associated with precocious puberty.

A female case of precocious puberty associated with HCG-producing ectopic pinealoma was reported. The patient, a 5-year-old girl, was referred to the hospital because of headache and choked discs. Physical examination revealed normal physical growth with breast enlargement. Endocrinological study revealed a high plasma HCG concentration of 1192 ng/ml with a normal FSH level. None of HCG, LH and FSH did respond to the LH-RH test. A partial resection of the tumor and an external X-ray irradiation relieved the symptoms and breast enlargement subsided with a remarkable decrease in the plasma HCG level. Histological examination revealed two-cell-pattern pinealoma and electron microscopic findings showed abundant secretory granules in the dark cells. HCG content in the tumor was as high was 400 ng/mg of acetone dried tumor tissue, but no FSH was detectable. Hitherto, all of the reported cases of precocious puberty associated with pineal tumors have been exclusively boys. A normal level of plasma FSH concentration with a somewhat elevated prolactin level might be a contributory factor for the development of precocial sexual development in the present case.

Child, Preschool↗
PubMed1976

Effect of hypophysectomy on hypothalamic somatostatin content in rats.

The effect of hypophysectomy on the hypothalamic somatostatin content was examined in rats. Somatostatin content in the acid extract of the pituitary stalk and the median eminence tissue (SME) was measured by specific radioimmunoassay. In young male rats, the mean somatostatin content in SME was 63.9+/-5.0 ng. Two weeks after hypophysectomy, it was reduced significantly to 34.4+/-3.3 ng. The result may indicate that the elimination of feedback actions of GH and/or TSH on the hypothalamus led to the decreased synthesis and/or the release of somatostatin. However, the possibility that structural changes in the pituitary stalk and the median eminence tissue ensued after hypophysectomy resulted in the depletion of somatostatin cannot be ruled out.

Animals↗