| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
The anterior lobe of a pituitary gland is comprised of hormone-producing granular cells and agranular cells. Agranular cells characterized by their star-like morphological features and specific ability of forming follicles have been named folliculo-stellate cells. Folliculo-stellate cells are also known to be coupled by gap junctions. These junctions are composed of transmembrane channels allowing the free transcellular exchange of small cytoplasmic molecules such as ions, amino acids, sugars and several second messengers. We have proposed that such an intercellular communication via gap junctions might have some fundamental importance in maintaining homeostasis throughout the interconnected folliculo-stellate cells (Mabuchi & Sakuma et al., 2004 ; Shirasawa & Sakuma et al., 2004 ; Kurita & Sakuma et al., 2004). On the other hand, conditions which cause leptin dysfunction are known to result in disturbances in reproductive capacity in the field of clinical medicine, however clarificati
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on of the mechanisms by which leptin can induce changes in the rate regulation over pituitary endocrine systems need further researches. Male Wistar rats, aged 7 weeks with weighing 250-300g, were used for the immunohistochemical and electro-physiological study. The distribution of the S-100 protein cell (folliculo-stellate cell) within anterior pituitary glands is investigated by using immunohistochemical methods. Immunostained pituitary sections with S-100 protein antibody were photographed using a CCD camera equipped with a computer. The S-100 protein cells were then measured using NIH image software, and the three-dimensional distribution of the cells was analyzed. The distribution of the cells observed in each serial section showed that S-100 protein cells were dense at the basal zone of the gland where the pars tuberalis adjoined the anterior and intermediate lobes (Sato G & Sakuma et al., 2005). In the electro-physiological study, there was one major group for the recordings from cells with similar deep resting membrane potentials, which indicated that two cells were electrically coupled. Carbenoxolone depolarized the membrane by 12.3+/-5.5 mV and reduced the amplitude of electrotonic potentials, and the response recovered by removal of carbenoxolone by the superfusate. The results strongly indicated that the folliculo-stellate cell system participated in the regulation of the anterior pituitary parallel with the portal vessel system, which was the main regulatory system for pituitary hormone secretion (Sato Y & Sakuma et al., 2005). Less
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