ORGANIZATION AND ACTIVITY IN THE PRE- AND POSTOVULATORY FOLLICLE OF NECTURUS MACULOSUS

Abstract

The established follicle envelope of Necturus maculosus consists of a layer of follicle cells (granulosa) surrounding the developing oocyte, a layer of theca comprised of connective tissue cells, fibers, and matrix, and a layer of serosal cells. The changes in shape and fine structure of these layers during differentiation accompanying oogenesis are described. The cells and capillaries of the follicle envelope are engaged in an extensive pinocytotic activity, the details of which are described. We used cytochemical techniques to analyze the activity of the follicle envelope with respect to lipid accumulation and alkaline phosphatase activity. Radioautographic results indicate that cells of the follicle envelope are capable of incorporating tritium-labeled uridine and amino acids at certain times during oocyte growth. A comparative analysis was made of the soluble proteins in follicle envelopes isolated from immature oocytes and of those in follicle envelopes isolated from nearly mature oocytes and in postovulatory follicles. After the oocyte is ovulated, the cells of the follicle envelope are converted into a postovulatory follicle. The cells of the postovulatory follicle undergo further differentiation resulting in their becoming actively engaged in the formation of a secretion, the details of which are described at the electron microscope level. Analysis of the postovulatory follicle by thin-layer chromatography and cytochemistry demonstrated the presence of a wide variety of lipid substances and the possible presence of steroid. That the postovulatory follicle may be engaged in steroid biosynthesis is also suggested by studies involving the demonstration of 3 -hydroxysteroid dehydrogenase activity with cytochemical techniques applied to frozen sections and to soluble proteins separated by gel electrophoresis.

Evidence for Follicle Wall Involvement in Ovulation and Progesterone Production by Frog (Rana pipiens) Follicles in vitro

“…Following proper hormonal stimulation in vivo and in vitro, follicular wall components and the oocyte undergo marked structural alterations in association with the processes of oocyte maturation and ovulation [l, 8,22,23,. This entity morphologically and physiologically separates oocytes from each other within the ovary as well as from the extra-ovarian environment.…”

“…This entity morphologically and physiologically separates oocytes from each other within the ovary as well as from the extra-ovarian environment. Following proper hormonal stimulation in vivo and in vitro, follicular wall components and the oocyte undergo marked structural alterations in association with the processes of oocyte maturation and ovulation [l, 8,22,23,. Pituitary gonadotrophins as well as certain steroids have been shown to induce ovulation andor oocyte maturation to varying degrees under in vivo and in vitro conditions [lo, 13, 14, 16, 17, 19-21,26, 291.…”

Studies on the formation of compound yolk in the developing oocytes of an air-breathing fish Channa punctatus (Bloch).

“…The blebbing of the nuclear membrane by evagination and its subsequent constriction and passing out with intact nucleoli is another convincing argument in favour of nuclear participation during yolk deposition. Blebbing of the nuclear membrane by evagination in a large number of vertebrate oocytes in the beginning of vitellogenesis has been frequently marked (Anderson 1974) and the blebs so formed subsequently constrict and pass out in the ooplasm (Kessel 1968). The acidophilic nucleolar extrusions showing slightly B-metachromasia at stage IV, V and VI of the oocyte have been marked in close association with the acidophilic developing yolk globules where they disintegrate.…”

Metabolic and Ultrastructural Changes in the Frog Ovarian Follicle in Response to Pituitary Stimulation

“…The lack of smooth muscle fibers in the follicle wall leaves open the source of contractions that have been observed by many workers . Other reports on the ultrastructure of the frog ovarian follicle (19)(20)(21) have also failed to show any smooth muscle fibers, although it is not apparent that they were actively sought . Perhaps, there are such fibers in interfollicular septa .…”

“…Further, some of the apparently ripe follicles do not rupture . Because of the above considerations, it is not possible, as it is in the rabbit (19), to know that a given follicle would have gone on to ovulate within a predictable period of time .…”