FSH stimulation of cytosolic protein synthesis in cultured pig Sertoli cells

Culture of intact Sertoli/germ cell units and isolated Sertoli cells from Squalus testis: I. Evidence of stage-related functions in vitro

As part of an ongoing program of research using the testis of the dogfish shark (Squalus acanthias) to characterize morphologic and functional changes during spermatogenesis, we have developed procedures for culturing intact spermatocysts (germ cell/Sertoli cell clones) and isolated Sertoli cells from premeiotic, meiotic, and postmeiotic stages of development. Phase contrast and light microscopy confirmed the stage and cellular composition of spermatocysts and showed that they retained their closed, spherical configuration for at least 15 d in culture. Stage-related variations in [3H]thymidine incorporation (premeiotic much greater than meiotic = postmeiotic) were observed, a pattern that was the same quantitatively and qualitatively after one or seven days of culture. [3H]Leucine-labeled protein synthesis was twofold greater in cultures with premeiotic spermatocysts than in cultures with more mature stages, whether medium or cysts were analyzed. Sertoli cells isolated from spermatocysts of different stages differed in size, shape, cytological appearance, ability to form flattened monolayers, and rate of DNA synthesis. One day after seeding, [3H]thymidine labeling of Sertoli cells corresponded to the pattern obtained with intact spermatocysts (premeiotic much greater than meiotic = postmeiotic); however, 7 days in culture effected a 40- to 200-fold increase in this parameter and altered the stage-dependent pattern (premeiotic = meiotic greater than postmeiotic). Also, when [3H]leucine-labeled macromolecules secreted by Sertoli cells from premeiotic versus meiotic stages were analyzed by polyacrylamide gel electrophoresis (PAGE), banding patterns differed. Initial results demonstrate the feasibility and potential of this in vitro system for studying qualitative and quantitative changes during spermatogenesis.

Hormonal regulation of proteins secreted by cultured pig Sertoli cells: characterization by two-dimensional polyacrylamide gel electrophoresis

Using a primary culture of immature porcine Sertoli cells, we studied the effect of porcine FSH (pFSH), testosterone and retinoic acid on the labelled secreted protein. Cells were cultured in a chemically defined medium for 3 days and, on day 3, they were incubated for different times in another medium containing labelled amino acids either in the presence or absence of pFSH (50 ng/ml or 2 micrograms/ml), or testosterone (10(-6) M), or retinoic acid (10(-7) M), either alone or in several combinations. After 4 and 8 h of incubation, 20 and 30 secreted peptides were detected respectively by a two-dimensional polyacrylamide gel electrophoresis of the radiolabelled secreted proteins. During these 2 periods, the effect of pFSH was negligible. After 25 h, about 84 spots (pI in the range of 5-8) were identified on the autoradiograms. pFSH (2 micrograms/ml) induced an increase of 14 spots, and a decrease of 7, but at 50 ng/ml only 5 spots were increased and one decreased. Retinoic acid alone induced the increase of one peptide, while testosterone alone or in combination with pFSH (50 ng/ml) did not modify the electrophoretic pattern. When pig Sertoli cells were treated with retinoic acid, testosterone and pFSH (50 ng/ml), the effects on secreted proteins were higher than those induced by pFSH (50 ng/ml) alone.