Cytogenesis of immunoreactive gonadotropic cells in the fetal rat pituitary at light and electron microscope levels

Abstract

The cytogenesis of immunoreactive gonadotropic cells in the fetal rat pituitary was analyzed at the light and electron microscope levels using the indirect peroxidase-labeled antibody method and antisera against ovine FSH (A-oFSH) and ovine LH (A-oLH), and its two subunits (A-oLHβ and A-oLHα). At the light microscope level, the first immunoreactive cells were detected on the seventeenth day postcopulation (dpc) with A-oLHβ. Cells immunochemically stained with A-oLHα and A-oLH were generally observed 24 hr later. At the electron microscope level, the first immunoreactive cells were detected on 16 dpc with A-oLHβ. These first immunoreactive cells were small, but already displayed some small secretory granules (80–120 nm). On 17 dpc, gonadotropic cells were stained with A-oLHβ as well as with A-oLHα and A-oFSH. On 18 dpc, the number and the size of immunoreactive cells began to increase. By 19 dpc, they displayed an important development of ergastoplasmic cisternae and Golgi zone. At term, nevertheless, the ultrastructural features of fetal gonadotropic cells still differed from those of adult gonadotropic cells.