Effects of etoposide on stage-specific DNA synthesis during rat spermatogenesis.
The stage-specific effect of etoposide on spermatogenic DNA synthesis was measured 1, 3 and 18 days after a single intraperitoneal injection of etoposide. Etoposide inhibited premitotic DNA synthesis most effectively at stages II-III and IV-V of the seminiferous epithelial cycle in which DNA synthesis of late spermatogonia takes place. Compared with control levels, DNA synthesis at stages II-III was maximally inhibited 43% and 57% at doses of 5 and 10 mg/kg, respectively, and at stages IV-V the maximal inhibition was 67% and 62%, at doses of 5 and 10 mg/kg respectively. Premeiotic DNA synthesis was not as vulnerable to the etoposide action as premitotic DNA synthesis, the maximal inhibition of premeiotic DNA synthesis was 39% and 41% compared with control at doses of 5 and 10 mg/kg, respectively. Induction of most probably repair-type DNA synthesis was demonstrated in stages I-III, VIIa-b and XII of the cycle. All the effects of etoposide were most apparent 1 and 3 days after treatment but had not totally disappeared 18 days after the treatment.
Hakovirta
H
H
Department of Anatomy, University of Turku, Finland.
Parvinen
M
M
Lähdetie
J
J
D000704:Analysis of Variance; D000818:Animals; D002453:Cell Cycle; D004247:DNA / Q000096:biosynthesis*; D004260:DNA Repair; D004261:DNA Replication / Q000187:drug effects*; D005047:Etoposide / Q000633:toxicity*; D008297:Male; D008540:Meiosis / Q000187:drug effects; D008938:Mitosis / Q000187:drug effects; D009153:Mutagens / Q000633:toxicity*; D051381:Rats; D013090:Spermatocytes / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects*; D013093:Spermatogonia / Q000187:drug effects
D009153:Mutagens; D005047:Etoposide; D004247:DNA