Rat anterior pituitary cells in vitro can partly reconstruct in vivo topographic affinities

Abstract

Hormone-producing cells in the rat anterior pituitary gland are not randomly distributed; rather, there are specific topographic affinities among five cell types (Noda et al., Acta Histochem. Cytochem. 2001;34:313-319). In this study we reconstructed these affinities, at least partially, in primary monolayer culture. Pituitary cells collected from adult male rats were enzymatically dispersed and cultured for 72 hr at a density of 1 ϫ 10 5 cells/cm 2 . We double-immunostained cells using antibodies against hormones, and then used confocal laser microscopy to examine the ability of the cells to attach to each other. We also statistically analyzed the affinity of all combinations of the five types of hormone-producing cells. We observed clusters by electron microscopy to identify junctional complexes between the cells. Confocal laser microscopy indicated that the features and attachment patterns of hormoneproducing cells in vivo were similar to those in vitro. Statistical analyses revealed that the rates at which the five types of hormone-producing cells attached to growth hormone (GH)-, prolactin (PRL), and luteinizing hormone (LH)-producing cells were unequal, which suggests there are specific topographic affinities. The specific rates of adrenocorticotropic hormone (ACTH)-producing cell attachment to GH cells, LH to PRL cells, and PRL to LH cells were high, whereas that of PRL attachment to PRL cells was low. In addition, the rates correlated with the data from our previous in vivo study. Ultrastructural observations revealed few junctional complexes between hormone-producing cells. These results indicate that anterior pituitary hormone-producing cells can attach to specific types of cells by means of specific and/or nonspecific adhesion factors, and can reconstruct the topographic nature of the pituitary gland. Anat Rec Part A 272A: 548 -555, 2003.

Anterior pituitary cell networks

“…There is no evidence for sorting of specific cell types into homotypic aggregates or specific polarization within the clumps (Baes and Denef, 1987), but there is distinct organization of cell types within the cultured aggregates (Pals et al, 2006(Pals et al, , 2008. The topographical affinities between different cell types observed in vivo are also recapitulated in these reaggregates (Allaerts et al, 1991), as well as in monolayer cultures (Noda et al, 2003). 3.…”

Distinctive localization of N‐ and E‐cadherins in rat anterior pituitary gland

“…Moreover, when completely dispersed cells of the anterior pituitary are applied to static culture, cells gradually gather to form clusters. Observation of cell clusters under electron microscopy has indicated homologous reassembly of folliculo-stellate cells and the presence of cell junctions among folliculo-stellate cells, but not among hormone-producing cells, as seen in tissue observation (Noda et al, 2003). These results indicate the involvement of various cell adhesion molecules in tissue construction of the anterior pituitary.…”

Characterization of adherens junction protein expression and localization in pituitary cell networks

“…Furthermore, when anterior pituitary cells are dissociated and cultured in suspension, they aggregate and form clusters after several days (Van der Schueren et al 1982, Denef et al 1989, Noda et al 2003; cell adhesion molecules are likely to be key components in this reaggregation process. Since the pituitary is constituted of several different cellular types and its relative composition is highly plastic, we reasoned that there could be specific patterns of expression of cadherins that mediate and sustain the identities of contacting cells in their networks, with the potential of also contributing to functional signaling within the gland.…”