In-vitro effects of FSH and testosterone withdrawal on caspase activation and DNA fragmentation in different cell types of human seminiferous epithelium.
BACKGROUND
Caspases are downstream elements of apoptosis-mediating pathways initiated by the Fas ligand/Fas receptor system which is supposed to play a central role in the regulation of apoptosis in the human seminiferous epithelium. However, caspase activity in different cell types of this epithelium has never been addressed.


RESULTS
We evaluated caspase activity and DNA integrity in Sertoli and germ cells within in-vitro cultured segments of human seminiferous tubules after induction of apoptosis by FSH or testosterone withdrawal. FSH withdrawal increased the incidence of DNA fragmentation in meiotic (primary spermatocytes) and post-meiotic (spermatids) germ cells without producing any detectable effect on caspase activity in these cells and without affecting DNA integrity or caspase activity in Sertoli cells. Testosterone withdrawal stimulated caspase activity and produced DNA fragmentation in Sertoli cells, but showed only a weak effect on DNA fragmentation in germ cells and did not alter germ cell caspase activity.


CONCLUSIONS
These findings confirm the central role of caspases in apoptosis of Sertoli cells. However, they also suggest that acute apoptosis of germ cells in the adult human testis occurs in a caspase-independent way and is controlled by Sertoli cells via an as yet undetermined mechanism.
Tesarik
Jan
J
Molecular Assisted Reproduction & Genetics, Gracia 36, 18002 Granada, Spain.
Martinez
Francisco
F
Rienzi
Laura
L
Iacobelli
Marcello
M
Ubaldi
Filippo
F
Mendoza
Carmen
C
Greco
Ermanno
E
D017209:Apoptosis; D020169:Caspases / Q000378:metabolism*; D046508:Culture Techniques; D053938:DNA Fragmentation / Q000187:drug effects*; D004334:Drug Administration Schedule; D004789:Enzyme Activation / Q000187:drug effects; D004848:Epithelium / Q000201:enzymology / Q000502:physiology; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008540:Meiosis; D012671:Seminiferous Tubules / Q000201:enzymology* / Q000502:physiology; D012708:Sertoli Cells / Q000166:cytology / Q000201:enzymology / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology / Q000502:physiology; D013739:Testosterone / Q000008:administration & dosage* / Q000494:pharmacology
D013739:Testosterone; D005640:Follicle Stimulating Hormone; D020169:Caspases