title: Gonadotropin-releasing hormone is prerequisite for the constitutive expression of pituitary annexin A5.
abstract: Annexin A5 (ANXA5), a member of the structurally related family of annexin proteins, is expressed in pituitary gonadotropes. We previously reported that ANXA5 expression is stimulated by gonadotropin-releasing hormone (GnRH). In the present study, we investigated ANXA5 expression in the anterior pituitary gland of GnRH-deficient mutant hypogonadal (hpg) mice. RT-PCR demonstrated that luteinizing hormone β subunit (LHβ) and ANXA5 mRNA levels were both lower in the pituitary gland of hpg mice than in wild-type mice. Immunohistochemistry showed that ANXA5 expression throughout the pituitary gland was very low in hpg mice, suggesting that ANXA5 is diminished in gonadotropes and also in other cell types. Subcutaneous administration of a GnRH analogue, des-gly10 (Pro9)-GnRH ethylamide (1 μg/day for 7 days), augmented the expression of LHβ and ANXA5 in the pituitary gland in hpg mice. However, LHβ- and ANXA5-positive cells did not show exactly matched spatial distributions. These findings suggest that GnRH is necessary for constitutive ANXA5 expression in the pituitary gland, not only in gonadotropes but also in other pituitary gland cell types. A close relationship between ANXA5 and LHβ expression was confirmed. It is suggested that a significant role of ANXA5 in the physiologic secretion of LH.
authors.affiliation: Laboratory of Veterinary Physiology, School of Veterinary Medicine, Kitasato University, Aomori 034-8628, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yonezawa
authors.forename: Aiko
authors.initials: A
authors.lastname: Watanabe
authors.forename: Shiro
authors.initials: S
authors.lastname: Kurusu
authors.forename: Mitsumori
authors.initials: M
authors.lastname: Kawaminami
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D015870:Gene Expression; D007987:Gonadotropin-Releasing Hormone / Q000172:deficiency* / Q000235:genetics / Q000502:physiology*; D007006:Hypogonadism / Q000235:genetics; D007150:Immunohistochemistry; D007986:Luteinizing Hormone / Q000378:metabolism; D037101:Luteinizing Hormone, beta Subunit / Q000235:genetics; D051379:Mice; D008817:Mice, Mutant Strains; D010903:Pituitary Gland, Anterior / Q000737:chemistry / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D017304:Annexin A5; D037101:Luteinizing Hormone, beta Subunit; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone