Table 1.

Steroid binding and transcriptional activation of the Xenopus AR and PR

	Transcription			Binding
	Steroid	Fold induction	Percent inhibition	Steroid	fmol bound
AR	Ethanol	1.0  ± 0.1	—	—	—
	100 nM prog	1.0  ± 0.02	—	5 nM prog	30  ± 19
	5 nM test	37  ± 6.0	0	5 nM test	58  ± 14
	5 nM test + 20 μM flut	16  ± 8.0	60	—	—
	100 nM AD	18  ± 12	0	—	—
	100 nM AD + 20 μM flut	3  ± 1.0	83	—	—
PR	Ethanol	1  ± 0.1	—	—	—
	100 nM prog	23  ± 7	—	5 nM prog	65  ± 4
	100 nM test	1  ± 0.3	—	5 nM test	8  ± 0.5
	100 nM AD	1  ± 0.4	—	—	—

Transcriptional activation of AR was measured in CV1 cells transfected with the Xenopus AR, whereas PR activation was measured in COS cells transfected with the Xenopus PR. Cells were incubated with the indicated steroids and inhibitors for 48 h and results are displayed as fold-induction ±SEM (n = 3) over the signal from cells treated with ethanol alone. Values were corrected for β-galactosidase expression. Similar experiments were performed three times with similar results. Binding activity was measured by using COS cells transfected with either AR or PR and incubated with the indicated radiolabeled steroid. Binding is displayed as fmol of steroid specifically bound per well (24-well plate) ±SEM (n = 3). Background (counts bound to mock-transfected cells) has been subtracted. prog, progesterone; test, testosterone; flut, flutamide.