Table 1.

Numbers of dams and their pups used in this study

	Pup #
			III
Study Series	I	II	a	b	IV	V	VI	Dams #
Ctrl	7	6	9	8	7	5	8	17
PNE	7	6	10	8	7	5	8	19
Subtotal	14	12	35		14	10	16
Total	101							36

I -VI represent 6 Study Series, and a and b represent the experimental subset in each Study Series. No more than 3 male pups from each litter were used to minimize the possible effect of genetic difference among litters on the results. 13 adult males were used for breeding. Ctrl, control; PNE, prenatal nicotinic exposure.