Intra-acrosomal organization of a 90-kilodalton antigen during spermiogenesis in the rat

The localization of an acrosomal protein was studied using a monoclonal antibody MN7 raised against mouse spermatozoa. MN7 specifically recognized the anterior acrosome of several mammalian (mouse, rat, hamster) spermatozoa fixed with paraformaldehyde. An immunoblot study with periodate treatment showed that MN7 recognized a carbohydrate region of a 90 kDa protein in an extract of mouse and rat cauda epididymal spermatozoa. The change in distribution of the MN7 antigen during acrosome development was investigated in the rat testis using the pre-embedding immunoperoxidase technique. The antigen first appeared in the proacrosomic granules of spermatids in steps 1–2. Small vesicles adjacent to the outer acrosomal membrane and the developing acrosomic system were immunoreactive during steps 4–7. The majority of the antigen was then redistributed to the head-cap portion during steps 8–18, and finally restricted to the anterior acrosome in the step 19-spermatid. These results suggest that the antigen is transported to the acrosome by way of the vesicles that originate from the Golgi apparatus during early spermiogenesis, and are then delivered to the final destination within the acrosome by the intra-acrosomal migration during late spermiogenesis.     

Molecular forms of atrial natriuretic polypeptides circulating in human plasma

Molecular forms of atrial natriuretic polypeptides circulating in human plasma were analyzed by chromatographic separation, coupled with radioimmunoassay. Analyses were done with human plasma samples taken from 24 human subjects, divided into groups of healthy volunteers, patients with renal disease, and patients with heart disease, with 8 subjects in each group. Although alpha-hANP was found as a major circulating form in most of the plasma specimens (16 cases), beta-hANP accompanied by alpha-hANP was found in 6 cases including 2 healthy volunteers. In addition, hANP-immunoreactive macromolecule, which is likely a bound form of hANP, was found to some extent in all the specimens tested. Diversity of human plasma in ANP molecular distribution was discussed in connection with a radioimmunoassay for plasma ANP.