Ultrastructural localization of prolactin in the rat anterior pituitary glands by preembedding peroxidase-labeled antibody method: observations in normal, castrated, or estrogen-stimulated specimen.

Abstract

Ultrastructural localization of prolactin (PRL) was studied immunocytochemically (preembedding peroxidase-labeled antibody method) in a variety of pituitaries, including those from 1) normal, 2) castrated, and 3) castrated and estrogen-stimulated rats. In the normal rat, PRL was observed in cisternae of the rough endoplasmic reticulum (RER), perinuclear spaces, Golgi saccules, and secretory granules. In the castrated rats, PRL cells were rather atrophic and were filled with many small PRL-positive secretory granules. RER and Golgi saccules were rather inconspicuous and were almost devoid of PRL localization. The serum PRL level was markedly lowered. With estrogen stimulation after castration, the serum PRL level was markedly elevated and PRL cells showed a pronounced increase of PRL filled cisternae in the RER. From these observations, the role of secretory granules, Golgi apparatus, and RER in hormonal secretion was defined, and it was postulated that some peptide hormones would be secreted along two alternative pathways, i.e., either 1) a long (regulated) pathway or 2) a short (accelerated) pathway, in accordance with their secretory activities, which could be altered by various stimulations such as the use of estrogen.

Effects of Estrogens on the Ultrastructural Characteristics of Female Rat Prolactin Cells as Evaluated by in situ Hybridization in Combination with Immunogold Staining Technique

“…The present results, while confirming these pre vious results, clearly demonstrate that castration induces an al most complete disappearance of the classical PRL cells, the ma jority of PRL cells being constituted of the small-granule-con taining cell type and another cell type named intermediate PRL cell which contains both large and small granules. Osamura et al [8] have already reported that, in castrated female rats, the PRL cells identified by immunoeytochemistry were filled with many small secretory granules (120-190 nm in diameter). As for PRL mRNA [ 18] ( fig.…”

V-1 Electron Microscopy

“…LDH isozymes in the liver were studied by Yamashita et al (1979), and aldolase isozymes were examined in various organs . Prolactin was demonstrated in the rat hypophysis as well as in human adenoma in the cisternae of the endoplasmic reticulum, the perinuclear space and Golgi saccules (Osamura et al, 1980(Osamura et al, , 1982. ACTH and TSH cells were identified in the rat pituitary by Kawarai (1980).…”

Ultrastructural localization of CA 19-9 in ovarian cancer.

“…Immunoelectron microscopic observation: For electron microscopic observation of CA 19-9, the indirect immunoperoxidase method was used (10,12). Small pieces of tissues were fixed in periodate-lysine-paraformaldehyde soltuion (PLP) (9) at 4°C for 30 min.…”