The rough endoplasmic reticulum and the Golgi apparatus visualized using specific antibodies in normal and tumoral prolactin cells in culture.

Abstract

Antibodies directed against membrane components of dog pancreas rough endoplasmic reticulum (A-RER) and rat liver Golgi apparatus (A-Golgi) (Louvard, D., H. Reggio, and G. Warren, 1982, J. Cell Biol. 92:92-107) have been applied to cultured rat prolactin (PRL) cells, either normal cells in primary cultures, or clonal GH3 cells. In normal PRL cells, the A-RER stained the membranes of the perinuclear cisternae as well as those of many parallel RER cisternae. The A-Golgi stained part of the Golgi membranes. In the stacks it stained the medial saccules and, with a decreasing intensity, the saccules of the trans side, as well as, in some cells, a linear cisterna in the center of the Golgi zone. It also stained the membrane of many small vesicles as well as that of lysosomelike structures in all cells. In contrast, it never stained the secretory granule membrane, except at the level of very few segregating granules on the trans face of the Golgi zone. In GH3 cells the A-RER stained the membrane of the perinuclear cisternae, as well as that of short discontinuous flat cisternae. The A-Golgi stained the same components of the Golgi zone as in normal PRL cells. In some cells of both types the A-Golgi also stained discontinuous patches on the plasma membrane and small vesicles fusing with the plasma membrane. Immunostaining of Golgi membranes revealed modifications of membrane flow in relation to either acute stimulation of PRL release by thyroliberin or inhibition of basal secretion by monensin.

Light and Electron Microscopic Immunocytochemistry of TSH-like Cells Occurring in the Pars tuberalis of the Adult Male Rat Pituitary.

“…After perfusion fixation, the PT was removed and postfixed in the same fixative without glutaraldehyde overnight at 4t. The tissue samples were subjected to electron microscopic immunocytochemistry by a modification of the pre-embedding method described by ToUGARD et al (1983). From fixed samples of the PT attached by the hypothalamus, 40um-thick frontal sections through the region of the PT were made with a microslicer (Dosaka EM Co., Ltd. Japan).…”

Use of pre‐embedding ultrastructural immunocytochemistry in the localization of a secretory product and membrane proteins in cultured prolactin cells

“…We also review previously reported data concerning two types of intracellular antigens including 1) the subcellular localization of the secretory product, prolactin, in normal and tumor cells (Tougard et al, 1980a(Tougard et al, ,b, 1982; and 2) the subcellular localization of membrane components in intracellular compartments involved in the process of secretion and endocytosis (Tougard et al, 1983(Tougard et al, , 1985. These immunocytochemical results are discussed in relationship to others in the literature concerning this field.…”

Intracellular Traffic of Secreted Peptides -A Morphological Point of View

“…The secretory granule membrane remained completely un stained [37], Antibodies against two components of the secretory granule membrane of rat endocrine pancreas were recently obtained and stained specifically, by im munofluorescence, small structures in normal rat islets of Langerhans, anterior pituitary and adrenal medulla [33]. Antibodies against synaptophysin, a 38-kd integral membrane glycoprotein of synaptic vesicles [35,36], stained by immunofluorescence some small vesicles in anterior pituitary, adrenal medulla [38] and in GH3 cells [39], Recent findings [40,41] raised the possibility of the presence of a small amount of synaptophysin in the membrane of secretory granules of adrenal medulla.…”

“…Using polyclonal antibodies against some RER mem brane antigens and a 135-kd Golgi membrane antigen [28], we have clearly discriminated without any overlap ping between the two compartments in PRL cells in cul ture [37], The antibodies against the RER antigens stained the membrane of all RER cisternae, including the perinuclear cisterna whereas the antibodies against the Golgi membrane antigen stained the membrane of a Golgi subcompartment (medial to trans saccules). The secretory granule membrane remained completely un stained [37], Antibodies against two components of the secretory granule membrane of rat endocrine pancreas were recently obtained and stained specifically, by im munofluorescence, small structures in normal rat islets of Langerhans, anterior pituitary and adrenal medulla [33].…”

“…At the same time, a pro gressive disappearance of immunoreactive PRL content of the RER and of the Golgi saccules occurs followed then by a progressive reloading of these compartments which is consecutive to the TRH-stimulating effect on PRL neosynthesis [6]. TRH increases also the traffic of vesicles labeled with anti-Golgi antibodies between the Golgi zone and the plasma membrane [37], All these observations point out the importance of the Golgi zone in the TRH-induced stimulation of PRL release.…”