In vitro stimulation of stage-specific deoxyribonucleic acid synthesis in rat seminiferous tubule segments by interleukin-1 alpha.
Levels of rat testicular interleukin-1-like factor (tIL-1) have been shown to correlate with DNA synthetic activity during the cycle of the rat seminiferous epithelium, suggesting its role as a spermatogonial or meiotic growth factor. To explore this further, a new in vitro model system was developed. Rat seminiferous tubule segments from stages I, V, VIIa, and VIII-IX of the cycle were isolated by transillumination-assisted microdissection, cultured in chemically defined serum-free medium supplemented with human recombinant IL-1 alpha, and labeled with [3H]thymidine. During incubation, spontaneous progression of spermatogenesis was noted. Inactive stage VIIa tubule segments differentiated to stage VIII and initiated DNA synthesis, and concomitantly started to secrete IL-1-like factor. DNA synthesis of stages VIII-IX ceased through differentiation of spermatocytes to leptotene-zygotene (stages XII-XIII of the cycle). IL-1 alpha stimulated DNA synthesis significantly in spermatogonia of stage I. Meiotic DNA synthesis at stage VIIa was stimulated (48 h/34 C) and maintained at stages VIII-IX (48 h/34 C). IL-1 alpha seems to act as a regulator of spermatogenic DNA synthesis in both mitotic and meiotic phases. It has mainly stimulating and maintaining effects, but it may also be inhibitory under certain conditions.
Parvinen
M
M
Pediatric Endocrinology Unit, Karolinska Hospital, Stockholm, Sweden.
Söder
O
O
Mali
P
P
Fröysa
B
B
Ritzén
E M
EM
D000818:Animals; D001345:Autoradiography; D002453:Cell Cycle / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects*; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000494:pharmacology; D016196:S Phase / Q000187:drug effects; D012671:Seminiferous Tubules / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013091:Spermatogenesis / Q000187:drug effects; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D007375:Interleukin-1; D011994:Recombinant Proteins; D014316:Tritium; D013936:Thymidine