著者

HISANORI MINAKAMI Kozo KIMURA KUNIHIKO IJIMA TARO TAMADA

出版者

The Japan Endocrine Society

雑誌

Endocrinologia Japonica (ISSN:00137219)

巻号頁・発行日

vol.32, no.5, pp.645-651, 1985 (Released:2011-01-25)

参考文献数

35

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Although estrogen is known to stimulate the secretion of prolactin, there are only slight differences between the prolactin levels in the follicular and luteal phases in normal women. To test the hypothesis that progesterone is involved in the regulation of prolactin release, 50mg of progesterone was administered intramuscularly at 0600h to twelve hypogonadal women and blood samples were obtained at 15min intervals between 1500 and 2000h to determine the prolactin levels. The day before progesterone treatment, control blood samples were obtained at 15 min intervals between 1500 and 2000h. The serum progesterone levels were 28.7±4.1ng/ml at 1500h, 24.2±3.5ng/ml at 1730h and 21.3±2.9ng/ml (mean±SD) at 2000h. In eight of twelve hypogonadal women, progesterone lowered circulating prolactin levels significantly. These results indicate that a high level of progesterone in the luteal phase may partly block estrogen-induced prolactin release physiologically.

著者

Fumiaki Kono Kazuo Kurihara Taro Tamada

出版者

The Biophysical Society of Japan

雑誌

Biophysics and Physicobiology (ISSN:21894779)

巻号頁・発行日

vol.19, pp.e190009, 2022 (Released:2022-04-16)

参考文献数

35

被引用文献数

5

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Hydrogen atoms and hydration water molecules in proteins are essential for many biochemical processes, especially enzyme catalysis. Neutron crystallography enables direct observation of hydrogen atoms, and reveals molecular recognition through hydrogen bonding and catalytic reactions involving proton-coupled electron transfer. The use of neutron crystallography is still limited for proteins, but its popularity is increasing owing to an increase in the number of diffractometers for structural biology at neutron facilities and advances in sample preparation. According to the characteristics of the neutrons, monochromatic or quasi-Laue methods and the time-of-flight method are used in nuclear reactors and pulsed spallation sources, respectively, to collect diffraction data. Growing large crystals is an inevitable problem in neutron crystallography for structural biology, but sample deuteration, especially protein perdeuteration, is effective in reducing background levels, which shortens data collection time and decreases the crystal size required. This review also introduces our recent neutron structure analyses of copper amine oxidase and copper-containing nitrite reductase. The neutron structure of copper amine oxidase gives detailed information on the protonation state of dissociable groups, such as the quinone cofactor, which are critical for catalytic reactions. Electron transfer via a hydrogen-bond jump and a hydroxide ion ligation in copper-containing nitrite reductase are clarified, and these observations are consistent with the results from the quantum chemical calculations. This review article is an extended version of the Japanese article, Elucidation of Enzymatic Reaction Mechanism by Neutron Crystallography, published in SEIBUTSU-BUTSURI Vol. 61, p.216–222 (2021).