Fernández Silvina, Córdoba Mariana
Cátedra de Química Biológica, Instituto de Investigación y Tecnología en Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Av. Chorroarín 280 1427 Ciudad Autónoma de Buenos Aires, Argentina.
Cátedra de Química Biológica, Instituto de Investigación y Tecnología en Reproducción Animal, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Av. Chorroarín 280 1427 Ciudad Autónoma de Buenos Aires, Argentina.
Anim Reprod Sci. 2016 Jan;164:90-6. doi: 10.1016/j.anireprosci.2015.11.016. Epub 2015 Nov 19.
Progesterone (P4) is capable of inducing acrosome reaction in many species. The objective of this study was to determine the activity of enzymes involved in metabolism that contribute to the redox state and supply energy for acrosome reaction in cryopreserved bull spermatozoa. To accomplish this aim, acrosome reaction was induced by P4 in capacitated and non-capacitated samples. Alanine and aspartate aminotransferases (ALT, AST) and creatine kinase (CK) activities were measured spectrophotometrically at 340 nm after acrosome reaction with P4. Oxygen consumption was measured polarographically. ALT and AST activities increased by the addition of P4 capacitated and non-capacitated samples. P4 addition provoked an increase in CK activity in non-capacitated spermatozoa compared to heparin capacitated spermatozoa with or without P4 addition. P4 increased oxygen consumption, the percentage of acrosome reacted spermatozoa as well as the absence of acrosome integrity in both capacitated and non-capacitated bovine spermatozoa, but oxygen consumption in P4 samples was significantly lower than in heparin capacitated spermatozoa (P<0.05). Acrosome reaction induction by P4 required different creatine kinase activity with the same oxygen consumption and transaminases level to maintain oxidative metabolism and redox state through reducing equivalents transfer between cytosolic and mitochondrial compartment. In conclusion, P4 induces a lower oxidative metabolism during acrosome reaction in bovine cryopreserved spermatozoa, compared to heparin induced capacitation process.
孕酮（P4）能够在许多物种中诱导顶体反应。本研究的目的是确定参与代谢的酶的活性，这些酶有助于氧化还原状态，并为冷冻保存的公牛精子顶体反应提供能量。为实现这一目标，在获能和未获能的样本中用P4诱导顶体反应。在与P4发生顶体反应后，于340nm处用分光光度法测定丙氨酸和天冬氨酸转氨酶（ALT、AST）以及肌酸激酶（CK）的活性。用极谱法测定氧气消耗。添加P4后，获能和未获能样本中的ALT和AST活性均增加。与添加或不添加P4的肝素获能精子相比，添加P4可使未获能精子中的CK活性增加。P4增加了获能和未获能牛精子的氧气消耗、顶体反应精子的百分比以及顶体完整性的缺失，但P4样本中的氧气消耗显著低于肝素获能精子（P<0.05）。P4诱导顶体反应需要不同的肌酸激酶活性以及相同的氧气消耗和转氨酶水平，以通过胞质和线粒体区室之间的还原当量转移来维持氧化代谢和氧化还原状态。总之，与肝素诱导的获能过程相比，P4在牛冷冻保存精子的顶体反应过程中诱导较低的氧化代谢。
