Fine structural observations on the form and distribution of nuage in germ cells of the rat

Abstract

Germ cells of the rat have been studied at the fine structural level from the time they are present in the epithelium of the embryonic gut until near the time of production of mature gametes in the adult. Particular attention has been paid to the form and location of dense, fibrous material (nuage) in the germ cells during that period of the life cycle. The nuage either exists as small discrete bodies in the cytoplasm or as “cementing material” situated in the interstices of mitochondrial clusters. It is present in primordial germ cells in the gut epithelium, in germ cells in indifferent gonads and in germ cells in sexually differentiated fetal, neonatal and adult rat gonads. It is sometimes associated with nuclear pores. Because it is present throughout much of the life cycle of the germ cells of male and female rats and it has been observed in various other mammals by previous workers, it is suggested here that it is a characteristic morphological feature of mammalian germ cells. In addition, there is considerable similarity in form and distribution of the nuage to the “polar granules” in insects and the “germinal plasm” in amphibians which are suggested to play a role in the determination of germ cells in these animals. The possibility that nuage may play a comparable role in mammals is considered.

Mouse oocytes within germ cell cysts and primordial follicles contain a Balbiani body

“…However, subsequent studies failed to confirm these observations, and it is now widely accepted that mouse oocytes lack such mitochondrial aggregates (1,2). This situation is surprising, because Balbiani bodies have been found in marsupials (29) and many mammalian species including goat (21), rat (30,31), hamster (32), and humans (33)(34)(35), although the function of mammalian Balbiani bodies is unknown.…”

Ovarian development in Wistar rat treated prenatally with single dose diisobutyl phthalate

“…Primordial germ cells (PGC) remain sequestered in the extra embryonic mesenchyme at the caudal end of the embryo until the embryonic endoderm is produced and gastrulation is completed, and then with folding of the embryo underway the PGCs begin their migration to yolk sac (16). These undifferentiated germ cells migrate towards and settle in sexually undifferentiated gonad (17,18). According to Kemper and Peters (1987) in rat on postcoital day 10, PGCs are found in the invaginating visceral yolk sac endoderm and the base of allantois.…”

Nuage Components and Their Contents in Mammalian Spermatogenic Cells, as Revealed by Immunoelectron Microscopy

“…In germ cells of both sexes, nuage appeared either as a discrete mass or in association with mitochondrial clusters during the different stages of oogenesis and spermatogenesis. Eddy (1974) suggested that that the CB was a component of the nuage in spermatogenic cells.…”