Laminin isoform expression during the anterior pituitary development of rat

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 164-196-Pituitary
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-192
Dini Ramadhani*, Takehiro Tsukada and Takashi Yashiro
Jichi Medical University School of Medicine
Anterior pituitary gland is a main endocrine organ where multiple cells including 5 types of hormone-producing cells are intermingled. The cells are arranged in lobule structure, which are compartmentalized by basemement membrane (BM). BM is specialized sheet-like extracellular matrix comprising laminin, type IV collagen, nidogen, and heparan sulfate proteoglycan. Especially, laminin binds to major cell surface receptors, integrins, and modulate cellular functions. Laminin comprises of one α, one β, and one γ chain forming into heterotrimeric isoform. Thus far, there are 11 laminin chains (α1-5, β1-3, γ1-3) present in mammals, generating 19 laminin isoforms (e.g laminin 121 comprises of α1, β2, and γ1 chains). Laminin isoforms are commonly expressed in a spatiotemporal manner and play distinctive role in the tissue development. Recently, we determined laminin isoforms expressed at adult rat anterior pituitary (gonadotroph: laminin 111, 121, endothelial cell: laminin 411, and some laminin 311) (1). However, laminin isoforms expressed during the anterior pituitary development remain unknown. In the present study, to characterize this isoform profile in the anterior pituitary development, we performed immunohistochemistry and in situ hybridization using Wistar rat. At embryonic day 12.5 (E12.5), we observed laminin-immunoreaction beneath the epithelial cell layer of Rathke’s pouch and in situ hybridization showed that the possible laminin isoforms were laminin 511, 521, 522, 523. At E19.5, where the vasculature is developed in the anlage, other laminin isoforms started to be expressed in different regions; laminin 411, 421, and limited amount of laminin 111, 121 were expressed in endothelial cells, laminin 511, 521, 522 were near the pituitary cleft. We also determined that the gonadotroph start to produce laminin 111 and 121 from postnatal day 10. These results strongly suggest that multiple laminin isoforms might be involved in the anterior pituitary development.

(1) Ramadhani D et al., Acta Histochem Cytochem 2012; 45: 309-315

Nothing to Disclose: DR, TT, TY

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Sources of Research Support: Murayama Foundation