Table 2.

Effects of progesterone and estrogen on neurons in the preoptic area. Progesterone data from Tsai et al. [155]. POA tissue slices from male and ovariectomized female rats were perfused with medium containing progesterone (3 ng.ml-1 and 30 ng.ml-1, which are within physiological ranges). There were no apparent sex or dose differences in responses so data were pooled. Estradiol data are from Silva and Boulant [16]. POA tissue slices were perfused in medium containing 17β-estradiol (30 pg.ml-1, which is within the physiological range). Progesterone 72 h after estradiol data are from Tsai et al. [156]. Ovariectomized rats were injected with 17β-estradiol benzoate (20 µg in 0.1 ml oil, subcutaneous) for 3 consecutive days before sacrifice. POA slices were then perfused with progesterone. In all cases, neurons that were excited or inhibited are shown; the remaining neurons showed no change to the hormones. See text for discussion.

	Progesterone		Estradiol		Progesterone 72 h after estradiol
Reference	154		16		155
Effect	Excited	Inhibited	Excited	Inhibited	Excited	Inhibited
Warm-sensitive neurons	5/31 (16%]	19/31 (61%)*	7/27 (26%)	1/27 (4%)	16/42 (38%)	4/42 (10%)
Temperature- insensitive neurons	3/26 (12%)	4/26 (15%)	2/22 (9%)	1/22 (5%)	1/21 (5%)	5/21 (24%)
Cold-sensitive neurons	1/4 (25%)	3/4 (75%)	0/3 (0%)	0/3 [0%)	-	-