Effects of the aromatase inhibitor fadrozole on plasma sex steroid secretion, spermatogenesis and epididymis morphology in the lizard, Podarcis sicula

• Published in: Molecular reproduction and development 2002-09, Vol.63 (1), p.63-70
• Main Authors: Cardone, Anna, Comitato, Raffaella, Bellini, Luigi, Angelini, Francesco
• Format: Article
• Language: English
• Subjects: androgens; Animals; Aromatase Inhibitors; Biological and medical sciences; Enzyme Inhibitors - pharmacology; Epididymis - drug effects; Epididymis - ultrastructure; Estradiol - biosynthesis; Estradiol - blood; Estradiol - secretion; estrogens; fadrozole; Fadrozole - pharmacology; Fundamental and applied biological sciences. Psychology; Hormone metabolism and regulation; lizard; Lizards - physiology; Male; Mammalian male genital system; Periodicity; Reproduction - physiology; reproductive tract; Seasons; Spermatogenesis - drug effects; testis; Testis - drug effects; Testis - secretion; Testosterone - blood; Testosterone - secretion; Vertebrates: reproduction
• ISSN: 1040-452X; 1098-2795
• DOI: 10.1002/mrd.10151

Recently, increasing importance has been attached to the role of estrogens and their receptors in male reproduction, since they have been found to be abundant in the male reproductive tract. In the lizard, Podarcis sicula, a seasonal breeder, estrogens seem to be involved in the regulation of testicular activity. Particularly, it has been hypothesized that the block of spermatogenesis and the complete regression of the epididymis and other secondary sexual characters (SSCs) in autumn might be due to high estrogen levels. To investigate the role of estrogens in the reproductive process of male lizards, we utilized Fadrozole ((AI) [4‐(5,6,7,8‐tetrahydroimidazole [1,5‐a] pyridin‐5‐yl)‐benzonitrile monohydrochloride] (CGS 16949A)), a nonsteroidal inhibitor of aromatase, the enzyme involved in the aromatization of androgens to estrogens, evaluating its effects on plasma sex‐hormone release, spermatogenesis and epididymis morphology. For this purpose, adult male lizards, captured during the autumnal recrudescence, were intraperitoneally injected with 0.5 μg and 5 μg/g/body weight of AI for 15 and 30 days. In the animals treated with the higher AI dose, estrogen levels decreased if compared to the control groups, whereas androgen levels increased. Furthermore, histologic sections of testes and epididymes showed that the 30‐day treatment with AI‐induced spermatogenesis resumption with release of sperms into the large lumen of the seminiferous tubules, and the epididymes appeared more developed with moderately secreting columnar canal cells. Therefore, it is proposed that failure of spermatogenesis in autumn might be due to high estrogen levels. Mol. Reprod. Dev. 63: 63–70, 2002. © 2002 Wiley‐Liss, Inc.