Browsing by Author "Habara, Yoshiaki"

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    Lipid secretory mechanisms in the mammalian harderian gland
    (WILEY-LISS, 1996) Satoh, Yohichi; Gesase, Ainory Peter; Habara, Yoshiaki; Ono, Kazuyuki; Kanno, Tomio
    The mammalian Harderian glands are lipid-secreting glands. In an unstimulated condition, the glandular cells frequently exocytose the lipid materials; however, no intracellular calcium ion ([Ca2+l,) changes are detectable. Cholinergic (muscarinic) secretagogues induce secre tory activity and increase of [Ca2+lc. A Gprotein activator, sodium fluoride, enhances the secretory activity and increase of [Ca2+Ic. Removal of extracellular calcium ions inhibits the secretion en hanced by cholinergic stimulation. Under pharmacologic stimulation, glandular cells may show an apocrine-like secretory pattern. Cholinergic stimulation also induces contraction of the myoepithe lial cells covering glandular end pieces; however, the reduction in volume of glandular end pieces is not prominent. Catecholamines have no effect on the release of lipid materials. These results indicate the involvement of G-proteins linking with muscarinic receptors and Ca2+ dynamics (increase of [Ca2+l, and Ca2+ influx) in lipid secretion by glandular cells and in contraction of myoepithelial cells of mammalian Harderian glands. However, the increase of [Ca2 + I, in Harderian glands was less when compared with other cells-for instance, those which secrete protein. 0 1996 Wiley-Liss, Inc.