Folliculostellate cells in pituitary pars distalis of male viscacha: immunohistochemical, morphometric and ultrastructural study

Abstract

Folliculostellate cells (FSC) have been reported in pituitary of several mammalian species. FSC morphology and secreted substances have been instrumental to the understanding of their function. The purpose of this work was to perform an immunohistochemical, morphometric and ultrastructural study of the pituitary pars distalis FSC in adult male viscacha and to analyze their relation with hormone secreting cells. Immunohistochemistry and image analysis were carried out in different sectors of the gland, from the middle (sector 1) to the glandular periphery (sector 5). Transmission electron microscopy with lanthanum as electrodense tracer was used. FSC formed follicles with PAS-positive colloid inside. They expressed S-100 protein mainly in both nucleus and cytoplasm. FSC were stellate-like in shape and exhibited short cytoplasmic processes that contacted with blood vessels and endocrine cells. In addition, some follicular colloids were immunostained with anti-S-100 protein. A few FSC were immunostained with anti-glial fibrillary acidic protein (GFAP) and anti-vimentin. The morphometric parameters analyzed (percentages of S-100-positive total, cellular and colloidal areas) increased from sector 1 to sector 3 and then decreased to sector 5. Hormone secreting cells, mainly lactotrophs, gonadotrophs and corticotrophs were associated with FSC and follicles. The ultrastructural study demonstrated that FSC developed junctional complexes and desmosomes between their lateral membranes. Lanthanum freely penetrated the spaces between granulated cells and FSC, but did not penetrate into the follicular lumen. In conclusion: 1) the differential expression of S-100 protein, GFAP and vimentin may indicate different physiological stages of FSC; 2) the expression of these proteins suggests a neuroectodermic origin of these cells; 3) FSC spatial distribution, association with endocrine cells, and the generation of an intercellular communication network suggest that FSC are involved in the pituitary pars distalis paracrine regulation of the viscacha.

A Seasonal and Age‐Related Study of Interstitial Cells in the Pineal Gland of Male Viscacha (Lagostomus maximus maximus)

“…In this study, significant differences in the %IA of S‐100 protein and GFAP may indicate that IC undergo seasonal variations in their biochemical properties, in relation to seasonal changes in the pinealocyte activity. It has been reported that S‐100 protein acts as a cytoskeleton dynamics regulator, intracellular signal transducer as well as paracrine regulator at extracellular level (Donato, ; Donato et al, ; Acosta et al, ). In viscachas, the higher expression during winter may reflect a major activity of IC according to pinealocyte activity.…”

“…HK 183–5K; BioGenex, San Ramon, CA), resulting in a fuchsia precipitate. DAB and New Fuchsin were selected as chromogens to visualize the antigens, since this combination is known to provide good contrast (Acosta et al, ). The sections were counterstained with Harris′ hematoxylin for 10 sec, washed for 2 min in running water, and mounted with a permanent aqueous mounting medium (SuperMount, BioGenex San Ramon, CA).…”

“…The S‐100 protein was present in glial cells of the central nervous system (CNS), especially in astrocytes, maturing oligodendrocytes, neural progenitor cells, and some types of neurons. S‐100 expression has been documented in other cell types such as kidney epithelial cells, pituitary folliculostellate cells, chondrocytes, melanocytes, Langerhans cells, and myoblasts (Haimoto et al, ; Böni et al, ; Rambotti et al, ; Acosta et al, ; Acosta and Mohamed, ). Intracellularly, the S‐100 protein has been involved in the regulation of proliferation, differentiation, inflammation and migration, Ca 2+ homeostasis, energy metabolism, and apoptosis.…”

Interstitial Cells in the Pineal Gland of Pregnant and Nonpregnant Viscachas <b><i>(Lagostomus maximus maximus)</i></b>: A Morphometric and Biochemical Study

“…Genex), resulting in a fuchsia precipitate. DAB and new fuchsin were selected as chromogens to visualize the antigens, since this combination is known to provide good contrast [Acosta et al, 2010;Busolini et al, 2017]. The sections were counterstained with Harris' hematoxylin for 10 s, washed for 2 min under running water, and mounted with a permanent aqueous mounting medium (SuperMount; BioGenex).…”

“…The S-100 protein is the most commonly used marker protein for the identification of glial cells in the central nervous system, especially in astrocytes, neural progenitor cells, maturing oligodendrocytes, and some types of neurons. In other cell types, such as pituitary folliculostellate cells, Langerhans cells, melanocytes, and chondrocytes, expression of the S-100 protein has also been reported [Haimoto et al, 1987;Böni et al, 1997;Rambotti et al, 1999;Acosta et al, 2010;Acosta and Mohamed, 2013]. S-100 protein is exclusively expressed in vertebrates and performs several intracellular functions, as well as some extracellular ones.…”