Granulated folliculo-stellate cells and growth hormone cells immunostained with anti-S 100 protein serum in the pituitary glands of the goat

Abstract

Goat pituitary glands were immunohistochemically studied with antisera for bovine S-100 protein, rat LH beta, FSH, TSH beta, prolactin, ovine GH, and porcine ACTH1-39 by use of the superimposition technique on adjacent sections. Folliculo-stellate (F-S) cells were divided into two categories on the basis of ultrastructural properties: One consisted of a mass of agranular cells in which the pseudolumina were equipped with microvilli and cilia. Elongate gap junctions were often observed among these cells. The other was a group of granulated cells with or without pseudolumina. In this group the gap junctions were shown to be disintegrated. The dense granules 150-250 nm in diameter began to accumulate in the cells. However, neither type of these F-S cells was immunostained for S-100 protein. On the other hand, numerous polygonal, elongate, irregular or stellate cells containing S-100 protein were distributed throughout the gland. Most of them were immunohistochemically identical with the GH cells laden with the secretory granules 250-450 nm in diameter, but some of them were identical to TSH and prolactin cells which immunostained faintly for S-100 protein. This appears to be the first demonstration of GH cells intensely immunostained for S-100 protein.

Stem Cells in the Postnatal Pituitary?

“…Uptake in non-FS cells has also been described in other studies [98, 108]. On the other hand, the rare GH + AMCA + cells with stellate morphology may represent intermediate stages between FS cells and GH cells, and may be the in-vitro counterparts of the sporadic S100 + GH + granular stellate cells that have been identified in goat [109] and rat pituitary [97], S100 in the pituitary being regarded as the marker of FS cells (see Section 4). In view of the phagocytotic capacity attributed to FS cells [110], also the possibility has to be considered that GH (e.g.…”

“…The cytoplasmic extensions of FS cells seem to be longer than the ones described for follicular cells which display only short processes. Some FS cells may contain granules [97, 100, 109], whereas this has not been reported for follicular cells. Contrary to the finding of mitotic figures in follicular cells at all postnatal ages [19, 43], no bromodeoxyuridine (BrdU) incorporation was found in FS cells as analyzed at P15 and P30 in rat, and mitotic figures are completely absent from FS cells of human pituitary [24].…”

“…This challenging but attractive hypothesis is supported by some findings. S100 expression looks to be a mature feature since S100 expression is only detected from P10 in the rat, and secretory granules have been observed in some FS cells that express S100 [97, 109, 132]. S100 + FS cells do not seem to proliferate in the postnatal rat (as analyzed at P15 and P30) and the human pituitary [24], suggesting that S100 is expressed only after mitotic activity of the cells has ceased [99].…”

Identification and enrichment of colony-forming cells from the adult murine pituitary

“…In adults, FS cells have a characteristic stellate shape with long cytoplasmic processes, and are usually found lining the lumen of follicles that are scattered throughout the anterior lobe. Although FS cells are considered to be agranular, a small proportion of FS cells have been shown to contain secretory granules [17], which appear to exhibit GH immunopositivity [18]. These cells may be a transient intermediate that is formed during differentiation of FS cells into somatotropes.…”

Immunohistochemical localization of S100A1 and S100A6 in postnatally developing salivary glands of rats

“…No S100 reactivity in FS cells was apparent before day 6 and, after day 10, S100-positive cells increased in numbers with more marked staining (Shirasawa et al 1983). Also, in FS cells in the goat pituitary, S100-positive FS cells are identical to the growth hormone-secreting cells, showing secretory granules 250-450 nm in diameter coexpressing growth hormone, suggesting that S100 may be involved in the secretion of growth hormone in FS cells (Shirasawa et al 1984). Lloyd and Maillour (1988) described S100 and prolactin secretion in the hyperplastic rat pituitary gland treated with diethylstilbestrol (DES).…”