Steroidogenic and morphological characteristics of granulosa and thecal compartments of the differentiating rabbit corpus luteum in culture

Abstract

On the day after ovulation, the thecal tissue and associated mural granulosa lutein cells of the rabbit corpus luteum were separated from the granulosa lutein 'core' by dissection and these tissues were cultured separately or together (whole corpus luteum) in defined medium for 10 days on stainless-steel grids. The medium was changed completely every 24 h. Replicate tissues were cultured with testosterone (10 ng/ml), but no other hormones were added to the medium. Progesterone production increased during the first 2 days of culture for whole corpus luteum, granulosa lutein cells and the thecal compartment which also included granulosa lutein cells. After 3 days, the production of progesterone declined gradually, but was still detectable on Day 10. The production of the metabolite, 20 alpha-dihydroprogesterone, by whole corpus luteum was equal to or greater than that of progesterone. Without the addition of testosterone, the granulosa lutein cells produced little (10 pg/culture) oestradiol during 1 day of culture, but the thecal compartment and whole corpus luteum each produced about 100 pg/culture on Day 1 and declining quantities over the next 2 days. In the presence of testosterone added to the medium, the formation of oestradiol was greatly increased for all tissues for 5-6 days of culture, after which time oestradiol was no longer detectable with or without testosterone in medium. Transmission electron microscopy of cells after 10-12 days of culture revealed fine structure that is characteristic of luteal cells, including abundant smooth endoplasmic reticulum, lipid droplets, and junctions between the luteal cells. The corpus luteum in culture resembles the corpus luteum in situ in that steroidogenesis and differentiation can proceed for a period after ovulation without extrinsic hormonal stimulation.

Lipid droplets in cultured luteal cells in non-pregnant sheep fed different planes of nutrition

“…Lipid droplets in the CL or cultured luteal cells have been identified by using electron microscopy for several species including humans, rats, rabbits, cows and sheep (Blanchette, 1966;Enders, 1973;Schmidt et al, 1984;O'Shea et al, 1986O'Shea et al, , 1989Yuh et al, 1986;Fields et al, 1992;Fields and Fields, 1996;Towns et al, 1999). In our study, we not only identified presence and localization of LDs in LLC and SLC but we also quantified LDs demonstrating that the mean and median volume of individual LD was greater in SLC than LLC.…”

Prostaglandin- and Thromboxane-Producing Activity of Isolated Luteal Cells from Pseudopregnant Rabbits

“…Since growth factors, which are also effective in angiogenesis, stimulate prostaglandin biosynthesis (15), it could very well be that luteal prostaglandins are important factors for the regulation of blood flow in the corpus luteum. Studies with whole corpora lutea in culture (26) or perfusion technology could help to resolve this important issue in better understanding regulation of luteal function arid ovarian blood flow.…”