Martínez-Marcos Paula, Carvajal-Serna Melissa, Lázaro-Gaspar Sofía, Pérez-Pé Rosaura, Muiño-Blanco Teresa, Cebrián-Pérez José A, Casao Adriana
Grupo BIOFITER, Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Veterinaria, Instituto de Investigación de Ciencias Ambientales de Aragón (IUCA), Universidad de Zaragoza, Zaragoza, Spain.
Departamento de Producción Animal, Facultad de Medicina Veterinaria y de Zootecnia, Universidad Nacional de Colombia, Bogotá, Colombia.
Reprod Domest Anim. 2019 Dec;54(12):1643-1650. doi: 10.1111/rda.13574. Epub 2019 Oct 28.
The melatonin catabolism is very complex and not completely understood. Melatonin can be metabolized by free radical interaction, but also pseudo-enzymatically or by enzymatic pathways. We have previously detected the existence of melatonin-synthesizing enzymes and melatonin receptors MT1 and MT2 in the ram reproductive tract; thus, in order to start to elucidate melatonin catabolism in these organs, we have investigated the presence of the melatonin-catabolizing enzymes indoleamine 2,3-dioxygenase (IDO, both IDO1 and IDO2 isoforms) and myeloperoxidase (MPO) in testis, epididymis and accessory glands. Gene expression analyses by real-time PCR showed the presence of MPO, IDO1 and IDO2 in all the organs of the ram reproductive tract and revealed that MPO is the main melatonin-catabolizing enzyme, which is mainly expressed in the testis and the bulbourethral glands (p < .05). These results were further corroborated by immunohistochemical staining, and by Western blot. Likewise, MPO was also evidenced in epididymal and ejaculated spermatozoa by indirect immunofluorescence and Western blot. In conclusion, melatonin-catabolizing enzymes MPO, IDO1 and IDO2 are expressed in the ram reproductive tract, and MPO is the most expressed one, mainly in the testis and the bulbourethral glands. The presented results warrant further studies on the function of these enzymes and their melatonin-metabolizing activity.
褪黑素的分解代谢非常复杂，尚未完全被理解。褪黑素可通过自由基相互作用进行代谢，也可通过假酶促途径或酶促途径代谢。我们之前已检测到在公羊生殖道中存在褪黑素合成酶以及褪黑素受体MT1和MT2；因此，为了开始阐明这些器官中的褪黑素分解代谢，我们研究了睾丸、附睾和附属腺体中褪黑素分解代谢酶吲哚胺2,3-双加氧酶（IDO，包括IDO1和IDO2亚型）和髓过氧化物酶（MPO）的存在情况。通过实时PCR进行的基因表达分析表明，MPO、IDO1和IDO2存在于公羊生殖道的所有器官中，并揭示MPO是主要的褪黑素分解代谢酶，主要在睾丸和尿道球腺中表达（p <.05）。免疫组织化学染色和蛋白质印迹进一步证实了这些结果。同样，通过间接免疫荧光和蛋白质印迹也在附睾精子和射出精子中证实了MPO的存在。总之，褪黑素分解代谢酶MPO、IDO1和IDO2在公羊生殖道中表达，且MPO表达最多，主要在睾丸和尿道球腺中。所呈现的结果值得进一步研究这些酶的功能及其褪黑素代谢活性。
