Rangel P L, Sharp P J, Gutierrez C G
Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Cd. Universitaria.
Reproduction. 2006 Jun;131(6):1109-14. doi: 10.1530/rep.1.01067.
The preovulatory release of luteinizing hormone (LH) in the domestic hen occurs after the initiation of a preovulatory surge of testosterone. The objective of this study was to determine whether this testosterone surge has functional significance in the endocrine control of ovulation. Groups of laying hens (n = 10-22) were treated with the androgen receptor antagonist, flutamide, at 8 h intervals for 24 h at doses of 0, 31.25, 62.5, 125 and 250 mg. All doses reduced egg laying (P < 0.001), with the highest dose being the most effective. In a second study, laying hens (n = 9) were treated with 250 mg flutamide at 8 h intervals for 24 h with a control group being given placebo (n = 10). Blood samples were taken for hormone measurements at 2 h intervals for 18 h starting 4 h before the onset of darkness. The percentage of hens laying per day did not differ between groups before treatment (control, 88% vs flutamide, 86%). Ovulation was blocked in all hens treated with flutamide within 2 days while the control hens continued to lay at the pretreatment rate (80%). Preovulatory surges of plasma testosterone, progesterone, oestradiol and LH were observed in control hens but with the exception of testosterone, flutamide treatment blocked the progesterone, oestradiol and LH surges. LH concentrations declined progressively with time in the flutamide-treated hens. It is concluded that inhibition of testosterone action blocks egg laying and the preovulatory surges of progesterone, luteinizing hormone and oestradiol demonstrating a key role for the preovulatory release of testosterone in the endocrine control of ovulation in the domestic hen.
在家禽中，促黄体生成素（LH）的排卵前释放发生在睾酮排卵前激增开始之后。本研究的目的是确定这种睾酮激增在排卵的内分泌控制中是否具有功能意义。将产蛋母鸡分组（n = 10 - 22），每隔8小时用雄激素受体拮抗剂氟他胺以0、31.25、62.5、125和250毫克的剂量处理24小时。所有剂量均降低了产蛋量（P < 0.001），其中最高剂量最为有效。在第二项研究中，将产蛋母鸡（n = 9）每隔8小时用250毫克氟他胺处理24小时，对照组给予安慰剂（n = 10）。从黑暗开始前4小时起，每隔2小时采集血样进行激素测量，持续18小时。处理前，两组每天产蛋母鸡的百分比无差异（对照组88%，氟他胺组86%）。所有用氟他胺处理的母鸡在2天内排卵受阻，而对照母鸡继续以处理前的速率产蛋（80%）。在对照母鸡中观察到血浆睾酮、孕酮、雌二醇和LH的排卵前激增，但除睾酮外，氟他胺处理阻断了孕酮、雌二醇和LH的激增。在氟他胺处理的母鸡中，LH浓度随时间逐渐下降。得出的结论是，抑制睾酮作用会阻断产蛋以及孕酮、促黄体生成素和雌二醇的排卵前激增，这表明睾酮的排卵前释放在家鸡排卵的内分泌控制中起关键作用。
