Table 1.

Estrogen response numbers

E2, M	Receptors, n
	10−9	10−11	10−12	10−14
E2-occupied ER/cell	30,000	15,000	3,000	30
PRL synthesis, %	100	50	10	0
Growth, %	100	100	90	50

The total number of ER/PR1 cell is ≈30,000.