Pituitary pars intermedia of Lagostomus maximus maximus: immunohistochemical study.

ACOSTA, MARIANO; FILIPPA, VERÓNICA; MOHAMED, FABIAN

Potrero de los Funes, San Luis.

Congreso; XXIV Reunión Anual de la Sociedad de Bilogía de Cuyo; 2006

Sociedad de Biología de Cuyo.

The viscacha (Lagostomus maximus maximus) is a rodent of nocturnal habits and seasonal reproduction that lives in the semiarid region of our country. The pituitary pars intermedia (PI) of Lagostomus shows a developed parenchyma with typical follicular structures and scanty blood vessels. There are granulated and non-granulated cells in the parenchyma of PI. Most of non-granulated cells are the folliculo-strellate (FS) cells. The aim of this work was to study the PI of this rodent by immunohistochemical technique. The antibodies anti-ACTH, anti-α-MSH, anti-S-100 and anti-GFAP were used. The FS cells show cytoplasmic and nuclear immunolabeling for S-100 and cytoplasmic immunolabeling for GFAP. There are immunoreactive cells limiting with the Rathke´s pouch. Sometimes the colloidal lumen shows immunolabeling for S-100 and GFAP proteins. The FS cells present cytoplasmic processes. The granular cells near the follicular structures show immunolabeling for ACTH and α-MSH. Our results in PI of viscacha demonstrate that there are melanotropes, corticotropes and FS cells in closely association. The intercellular network communication originated by FS cells is probably an alternative way for the hormonal distribution. Besides, the expression of S-100 and GFAP proteins might indicate a neuroectodermal origin of the FS cells.