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Biomedical subjects

R Nakano

Publications and source records attributed to R Nakano.

At least 253 records · Page 14Linked to original sources
PubMed1975

Ovarian response to exogenously administered human gonadotropins during the postpartum period.

Eighteen normal puerperal women received a combined administration of human menopausal gonadotropin (HMG) and human chorionic gonadotropin (HCG) and the ovarian response to these human gonadotropins was evaluated by the daily estimation of the 24 hour urinary excretion of total estrogens. Fourteen of the 18 subjects studied were responsive to the exogenously administered gonadotropins with a rise in the urinary estrogen excretion. Moreover, plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels during the postpartum period were low compared to normal cycle gonadotropin levels. Thus, it might be concluded that puerperal anovulation and amenorrhea during lactation might be due to hypophyseal gonadotropic dysfunction rather than to ovarian refractoriness.

Amenorrhea↗
PubMed1975

Effect of pituitary gonadotrophins on tritiated thymidine uptake by rat ovary. An autoradiographic study.

The effect of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on the follicular growth in the ovary of the hypophysectomized rat was investigated using autoradiography. The numbers of DNA-synthesizing nuclei in the granulosa cell were measured by autoradiography after flashlabelling with tritiated (3-H) thymidine. The frequency of 3-H-thymidine labelled nuclei in the granulosa cell enhanced in the presence of FSH. In contrast, LH had no significant effect on thymidine uptake. The result suggests that FSH stimulates follicle cell division, whereas LH does not.

Animals↗
PubMed1975

Pituitary responsiveness to synthetic luteinizing hormone releasing hormone (LH-RH) during the menstrual cycle and in female hypogonadism.

The pituitary responsiveness to synthetic luteinizing hormone releasing hormone (LH-RH) in female patients with primary and secondary hypogonadism was tested and compared with that in normal women with regular menstrual cycles. A 200 mug dose of synthetic LH-RH was injected intravenously into 15 normal menstruating women, 8 patients with primary hypogonadism and 5 patients with secondary hypogonadism and the serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) response to LH-RH was investigated using double-antibody radioimmunoassay. In normal women, the LH response to LH-RH in the preovulatory phase was greater than that seen in the follicular (p less than 0-05) and luteal phases (p less than 0-05) of the menstrual cycle. In contrast, no significant difference in the FSH response was demonstrated among the three different phases of the cycle. The serum LH response to LH-RH in primary hypogonadism was greater than that in the follicular (p less than 0-01) and luteal phases (p less than 0-01) of the cycle. The serum FSH response in primary hypogonadism was markedly greater than that in the follicular (p less than 0-01), preovulatory (p less than 0-01) and luteal phases (p less than 0-01) of the menstrual cycle. Conversely, the LH levels after LH-RH administration in secondary hypogonadism were significantly lower than in the follicular (p less than 0-01), preovulatory (p less than 0-01) and luteal phases (p less than 0-01) of the cycle. The FSH response in secondary hypogonadism was slightly below that in the follicular phase (p less than 0-05). Thus, the FSH response to LH-RH in primary hypogonadism and the LH response in secondary hypogonadism seemed to be sufficiently characteristic to have diagnostic value.

Adolescent↗
PubMed1975

Pituitary response to a new analog of luteinizing hormone releasing factor during the menstrual cycle.

A new analog of luteinizing-hormone-releasing factor, (Des-Gly-NH-2-10, Pro-ethylamide-9)-LHRF, was tested in healthy women with regular menstrual cycles. This synthetic nonapeptide amide was injected intravenously in a dose of 200 mug into 15 normal female volunteers in the follicular, preovulatory, and luteal phases of the menstrual cycle, and the serum LH and FSH responses were compared with those to the same dose of the synthetic decapeptide LHRF in 15 controls. The new analog exhibited significantly higher activity than the synthetic decapeptide LHRF in the release of LH in the follicular (P smaller than 0.05), preovulatory (P smaller than 0.01), and luteal phases (P smaller than 0.05). In contrast, no statistical significance in the magnitude of FSH response was demonstrated in any phase of the menstrual cycle. The serum LH and FSH response to the nonapeptide amide suggested a longer physiologic half-life of the new LHRF analog. The results are similar to a previous report in men with normal gonadal function, and a clinical usefulness for the new analog is expected.

Adult↗
PubMed1975

Ultrastructure of rat pituitary gonadotrophs after injection of synthetic luteinizing hormone releasing factor (LRF).

The effects of intracarotid injection of synthetic luteinizing hormone releasing factor (LRF) on the ultrastructure of pituitary gonadotrophs are reported. Chronically ovariectomized rats of the Sprague-Dawley strain pretreated with oestradiol and progesterone were sacrificed at zero time and at 30, 120 min after injection of 1 mug of synthetic LRF. A careful observation was made for evidence of granule extrusion from gonadotrophs following intracarotid injection of LRF, but no signs of granule extrusion were demonstrated. However, granule migration to the periphery of the cell was observed 30 min after LRF injection and the distribution of secretory granules recovered 2 hours after injection. The result of ultrastructural observations suggests that LRF plays an important role in releasing and synthesizing gonadotrophins in pituitary gonadotrophs. Further investigations should elucidate more clearly the morphologic aspect of mode of LRF action in pituitary gonadotrophs.

Animals↗
PubMed1975

Follicle-stimulating hormone response to luteinizing-hormone-releasing hormone in patients with hydatidiform mole.

The serum concentration of immunoreactive follicle-stimulating hormone (FSH) and FSH response to synthetic luteinizing-hormone-releasing hormone (LHRH) were investigated in 9 patients with intact hydatidiform moles and 3 patients with aborted moles. The serum concentration of FSH before and after intravenous administration of 200 mug of synthetic LHRH was measured by double antibody radioimmunoassay. Serum FSH was detectable but relatively low compared with the levels seen in the follicular phase of the normal menstrual cycle in all 12 patients. Furthermore, the 12 patients did not respond, or responded subnormally, to exogenously administered LHRH, and there was no significant elevation in serum FSH levels after LHRH injection. The result of the current study is in accord with that of our previous report on the serum concentration of FSH and FSH response to synthetic LHRH during normal pregnancy. Thus, it might be concluded that the follicle-stimulating activity of the anterior pituitary is suppressed by an unknown mechanism during molar pregnancy as well as normal pregnancy.

Adult↗