Induction of luteinizing hormone release by gonadal steroids in the ovariectomized domestic hen.

摘要: The ability of intramuscular injections gonadal steroids to exert a positive feedback action on LH secretion was investigated in the ovariectomized hen. Plasma measured by radioimmunoassay. Single progesterone (dose range: 0.05-10 mg/kg) or oestradiol benzoate 0.01-1 did not result an increase plasma concentration. After priming with 0.1 mg benzoate/kg alternate days for 7 and 0.5 progesterone/kg 5, 6 7, single injection day 8 0.1-2 caused concentration start increasing after 15 30 min. Peak reached around 1.5-2 h injection. magnitude response dose related. In contrast, failed stimulate release oestrogen-progesterone primed (O-P-OVX) A testosterone 0.1-2.0 ten out 12 O-P-OVX hens. small observed two remaining birds. When oestrogen omitted from schedule, observed. Increasing decreasing mount schedule modified following last This suggested that critical ratio required prime mechanism. It is that, hen, facilitated effect combination two-phase process. first phase, which depends presence blood progesterone; second ind .uctive only incremental change Oestrogen involved induceive phase.