Table 1. Serum Levels of Estradiol in Sham and OVX Rats After Administration of 17β-Estradiol at Three Doses.

Gonads	E state
	Control	Low E (10 μg/kg)	Metestrus	Medium E (50 μg/kg)	Proestrus	High E (150 μg/kg)	Pregnancy (GD 20–22)
Sham	48.7±12.7	20.2±3.2	20.6±1.6	120.6±14.0	142.2±45.8	628.4±95.0	628±210
OVX	5.5±0.6	17.9±3.5	—	125.8±15.7	—	660.4±59.4	—

Mean (±SEM) of serum level of estradiol 2 h after second injection (given 24 h apart) of 0, 10, 50, or 150 μg/kg of 17β-estradiol, in sham and OVX rats.

For comparison, levels found by Nequin et al (1979) along the cycle (metestrus and proestrus) and by Shaikh (1971) on gestation days (GD) 20–22 are provided.