title: In situ hybridization analysis of the temporospatial expression of the midkine/pleiotrophin family in rat embryonic pituitary gland.
abstract: Pituitary gland development is controlled by numerous signaling molecules, which are produced in the oral ectoderm and diencephalon. A newly described family of heparin-binding growth factors, namely midkine (MK)/pleiotrophin (PTN), is involved in regulating the growth and differentiation of many tissues and organs. Using in situ hybridization with digoxigenin-labeled cRNA probes, we detected cells expressing MK and PTN in the developing rat pituitary gland. At embryonic day 12.5 (E12.5), MK expression was localized in Rathke's pouch (derived from the oral ectoderm) and in the neurohypophyseal bud (derived from the diencephalon). From E12.5 to E19.5, MK mRNA was expressed in the developing neurohypophysis, and expression gradually decreased in the developing adenohypophysis. To characterize MK-expressing cells, we performed double-staining of MK mRNA and anterior pituitary hormones. At E19.5, no MK-expressing cells were stained with any hormone. In contrast, PTN was expressed only in the neurohypophysis primordium during all embryonic stages. In situ hybridization clearly showed that MK was expressed in primitive (immature/undifferentiated) adenohypophyseal cells and neurohypophyseal cells, whereas PTN was expressed only in neurohypophyseal cells. Thus, MK and PTN might play roles as signaling molecules during pituitary development.
authors.affiliation: Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan, ken_fuji@jichi.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Rita
authors.initials: R
authors.lastname: Maliza
authors.forename: Alimuddin
authors.initials: A
authors.lastname: Tofrizal
authors.forename: Khongorzul
authors.initials: K
authors.lastname: Batchuluun
authors.forename: Dini
authors.initials: D
authors.lastname: Ramadhani
authors.forename: Takehiro
authors.initials: T
authors.lastname: Tsukada
authors.forename: Morio
authors.initials: M
authors.lastname: Azuma
authors.forename: Kotaro
authors.initials: K
authors.lastname: Horiguchi
authors.forename: Motoshi
authors.initials: M
authors.lastname: Kikuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yashiro
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D017403:In Situ Hybridization; D000078792:Midkine; D010902:Pituitary Gland / Q000196:embryology / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; C066845:pleiotrophin; D000078792:Midkine