The monoclonal antibody (mAb), GZ1, is specific for a 42-kilodalton (kD) protein (designated GZ1-Ag) present among the plasma membrane (PM) proteins of the absorptive cells of rat intestine. This protein only occurs in the basolateral PM and is absent from the microvillus membrane. GZ2 and GZ20 are two other mAbs that are also directed against GZ1-Ag but which specify other antigenic determinants of this protein than mAb GZ1. Used together, these three mAbs allow better characterization of GZ1-Ag and more precise investigation of its distribution and localization in various rat cells. We performed immunohistochemical labelling for GZ1-Ag at both the light- and electron-microscope levels and found that GZ1-Ag is extensively distributed in rat epithelial tissues. However, the amount of this protein present in epithelial tissue shows considerable variation. GZ1-Ag is not present in the secretory cells of terminal portions of most excretory glands or in cells of the endocrine glands and liver. The cells of kidney tubules, except for collecting tubules, also lack GZ1-Ag. Only small amounts of GZ1-Ag are present in the cells of the stratified squamous epithelium and transitional epithelium, the exception being superficial cells. High concentrations of GZ1-Ag occur in the excretory duct systems of glands and in the various kinds of epithelium present in the male and female genital tract. Our results also indicated that the GZ1-Ag in all of these cells has a very similar structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Busulphan and Endoxan inhibit the normal course of ovarian follicular growth. Older secondary as well as an antral follicles perish within a very short time. Growing follicles, which at the beginning of the experiment exhibited only one layer, remained intact and single-layered during the entire duration of the experiment. The oocytes, however, continue growing, and the cytoplasmic structures, which are characteristic of older growing follicles, develop in them as well as in the follicle cells. Even a theca formation develops. In some of the "growing" follicles which have remained single-layered, after 10 days of Busulphan administration, some liquor folliculi is produced and accumulates in a fissure-shaped "antrum" between the zona pellucida and the follicular epithelium.

This study aimed to describe the distribution of a membrane protein called Gz-1-Ag in embryonal rat tissues using monoclonal antibodies. Three monoclonal antibodies recognizing different antigenic determinants of Gz-1-Ag were tested on different stages of rat embryos – fertilized oocytes two-cell stages morulae blastocysts and embryos up to 17.5 days old.The embryos were fixed by different methods; the Tokuyasu method was the most convenient. It yielded very good morphological conservation, good preservation of antigenicity and weak background fluorescence. Gz-1-Ag was detected in practically all early epithelial structures, but the intensity of fluorescence varied. Fluorescence was not associated with the germ layer from which the epithelium derived. The uninterrupted presence of Gz-1-Ag from the fertilized oocyte to all subsequently arising epithelial structures suggests a role of Gz-1-Ag in cell adhesion secretory processes or the intercellular exchange of information or substances.

The Wolffian duct and the developing Müllerian duct of 14 and 15 day old rat embryos were examined with the monoclonal antibodies GZ1 and GZ2. These antibodies react with antigens situated in the cell membrane of Wolffian cells; they do not react with Müllerian cells. This different antigen expression confirms the current opinion that these cells are of different types. A cellular contribution from the Wolffian duct to the developing Müllerian duct was not found.

The specific conditions of osmium fixation have been studied on gelatin gels and bovine pancreas. Protein (gelatin)-bound osmium can be quantitated by a modification of the Majumdar and Sen Gupta test, free and tissue (pancreas)-bound osmium by a modified Bahr test. Using these two methods, the depth of OsO4 penetration after increasing the times of fixation, the osmium concentration gradients and the total concentration of free and bound osmium at given spots within gelatin and tissue blocks have been determined. Warburg type experiments on suspended yeast cells and leukocytes demonstrate that 1% OsO4 stops cell respiration completely only after 40-min incubation. Formalin, 1%, is a more effective respiratory inhibitor.