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W. Löscher, H. Lüttgenau, W. Schlegel and S. Krüger

Summary. The pharmacokinetics of various non-steroidal anti-inflammatory drugs were determined to find dosage regimens by which drug concentrations known as active from human anti-inflammatory therapy could be reached and maintained in rabbits during continued administration. Based on the pharmacokinetics and side-effects of the different drugs, phenylbutazone was selected for the fertility experiments. Treatment of male rabbits with phenylbutazone for 9 consecutive days significantly reduced seminal concentrations of PGE-2 and PGF-2α and tended to increase ejaculate volumes, sperm motility, and fertility. These results indicate that, at least in rabbits, inhibition of PG synthesis by prolonged treatment with non-steroidal anti-inflammatory drugs does not impair male fertility. Instead, chronic treatment with the drugs at non-toxic doses may improve sperm quality and fertility.

Keywords: prostaglandins; anti-inflammatory drugs; rabbits; male fertility

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W. Schlegel, S. Krüger, D. Daniels, B. Fischer, H. P. G. Schneider and H. M. Beier

Summary. Corpora lutea and ovarian stromal tissue were anlaysed for prostaglandin (PG) concentrations and activities of enzymes involved in PG metabolism at 8, 10, 12, 13 and 15 days after induction of ovulation. In CL of pseudopregnant rabbits, the PGE-2–9-ketoreductase (PGE-2–9-KR) was highly active on Days 10, 12 and 15 when compared with Day 8 (P < 0·01; P < 0·001; P < 0·05). In pregnant animals PGE-2–9KR activity was only increased on Day 12 (P < 0·05) but declined to basal levels on Days 13 and 15. Comparing PGE-2–9-KR activity of pseudopregnant and pregnant animals, a significant elevation was found on Day 15 of pseudopregnancy (P < 0·025). Activities of PG-15-hydroxydehydrogenase did not exhibit any significant changes with time in pseudopregnant or pregnant rabbits.

PGE-2 concentrations were increased on Days 12, 13 and 15 (P < 0·025) when compared with Day 8. Changes in PGF-2α concentrations paralleled those of PGE-2–9-KR. The concentrations of PG metabolites 13,14-dihydro-15-keto-PGE-2 and -PGF-2α were lower than those of the primary PGs and did not show stage-specific changes in pseudopregnant and pregnant animals.

These results demonstrate that the rabbit CL posesses enzymes to convert PGE-2 to PGF-2α and to metabolize both PGs. PGE-2–9-KR may be involved in regulating the PGF-2α/PGE-2 ratio and possibly in controlling the life-span of the corpus luteum.

Keywords: PGE-2-9-ketoreductase; prostaglandin-15-hydroxydehydrogenase; luteolysis; prostaglandin metabolism; pseudopregnancy; rabbit

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G. R. Jones, A. G. Sacco, M. G. Subramanian, M. Kruger, S. Zhang, E. C. Yurewicz and K. S. Moghissi

Summary. Female rabbits (n = 36, 6 per group) were immunized with: (i) solubilized isolated porcine zona pellucida (SIZP), which contains ZP1, 82 kDa; ZP3α, 55 kDa; and ZP3β, 55 kDa; (ii) a purified preparation of ZP3α and ZP3β (ZP3); (iii) purified endo-β-galactosidase digested glycoproteins ZP3α-(EBGD) and (iv) ZP3β-(EBGD) (each about 30% deglycosylated); (v) chemically deglycosylated core proteins ZP3α-(DG) and (vi) ZP3β-DG (each > 92% deglycosylated). Rabbits injected with saline (n = 6) or Freund's adjuvant (n = 6) served as controls. Rabbits were bled weekly to monitor titres. Every six weeks two animals from each group (n = 16) were selected for unilateral oophorectomy followed by histological examination. Sections were scored for numbers of primary, secondary and tertiary follicles. Anti-ZP3 titres developed in all treatment groups and correlated with carbohydrate content (peak per cent [125I]labelled ZP3 binding by radioimmunoassay: SIZP 71·9 ± 1·2, ZP3 70·0 ± 2·5, ZP3α-EBGD 60·9 ± 5·3, ZP3β-EBGD 56·4 ± 5·0, ZP3α-DG 56·4 ± 4·0, ZP3β-DG 53·5 ± 4·3) (means ± sem). Animals immunized with SIZP, ZP3 and ZP3β-EBGD showed a statistically significant reduction in the number of primary, secondary and tertiary follicles compared with controls (P < 0·01, manova), whereas animals immunized with ZP3α-EBGD, ZP3α-DG and ZP3β-DG did not (P > 0·05, manova). These results demonstrate that immunization with purified ZP3α macromolecules (ZP3α-EBGD, ZP3α-DG) or ZP3β-DG does not produce histopathological changes in ovaries. Such deglycosylated ZP macromolecules represent potential target antigens for immunocontraceptive development.

Keywords: zona pellucida; deglycosylation; follicular development; ovarian histology; immunocontraception, rabbit

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Manhai Long, Alessandra Stronati, Davide Bizzaro, Tanja Krüger, Gian-Carlo Manicardi, Philip S Hjelmborg, Marcello Spanò, Alexander Giwercman, Gunnar Toft, Jens Peter Bonde and Eva C Bonefeld-Jorgensen

Persistent organic pollutants (POPs) can interfere with hormone activities and are suspected as endocrine disrupters involved in disorders, e.g. reproductive disorders. We investigated the possible relation between the actual integrated serum xenoestrogenic, xenoandrogenic and aryl hydrocarbon receptor (AhR) activities, and the sperm DNA damage and sperm apoptotic markers of 262 adult males (54 Inuits from Greenland, 69 from Warsaw (Poland), 81 from Sweden, and 58 from Kharkiv (Ukraine)) exposed to different levels of POPs. Xenobiotic-induced receptor activities were determined by receptor-mediated luciferase reporter gene expression. Sperm DNA damage was measured using terminal deoxynucleotidyl transferase-driven dUTP nick labeling assay (TUNEL) and pro- (Fas) and anti-apoptotic (Bcl-xL) markers were determined by immune methods. Different features of xenobiotic-induced receptor activity in serum and sperm DNA fragmentation and apoptotic markers existed between the Inuits and the European Caucasians. Negative correlations between xenobiotic-induced receptor activities and DNA damage were found for Inuits having relatively lower xenoestrogenic, lower dioxin-like activity, and lower sperm DNA damage, but higher xenoandrogenic activity. In contrast, in the European groups, xenobiotic-induced receptor activities were found to be positively correlated with the DNA damage. Further research must elucidate whether altered receptor activities in concerted action with genetic and/or nutrient factors may have protecting effect on sperm DNA damage of the Inuit population.