Study of the gonadotropic cells in the rat after chronic administration of met-enkephalin: light, electron microscope and image analysis

Abstract

The effects of a chronic administration of met-enkephalin (40 μg/day, for 20 days) on the pituitary gonadotropic cells of Wistar male rats were studied in light (PAS alcian blue-orange G and PAP-immunohisto-chemical for FSH and LH demonstration techniques) and by electron microscope. Also the D CIRCLE (mean diameter) and FORM PE (circular factor of form; irregularity degree) from secretory granules of these cell types were evaluated.

The cellular alterations are variable. Gonadotropic cells show an increase on the cytoplasmic basophilia and immunohistochemical reaction. At the electron microscope level the gonadotropic cells show an enlargement and dilatation of RER and Golgi apparatus. The secretory granules are bigger and more spherical in experimental than in normal and control animals. A lot of cells show a large cytoplasmic vacuole which is formed from dilated RER-cisternae.

The authors discuss the possible mechanism of action whereby met-enkephalin exerts control on gonadotropic cells.