Table 1.

Mass-spectrometric analysis of the concentration of steroids in the hippocampus and plasma of adult rats.

Sex steroids	Hippocampus (freshly isolated)a		Plasma		Hippocampus (acute slice)b
	Intactc	castrated	Intact	Castrated
17β-E2 (ng/g wet weight or mL)	2.3d (ne = 6)	1.9 (n = 16)	0.004 (n = 5)	0.002 (n = 14)
17β-E2 (nM)f	8.4	6.9	0.014	0.006	<0.5 (n = 5)
T(ng/g wet weight or mL)	4.9 (n = 8)	0.9 (n = 16)	4.2 (n = 8)	0.06 (n = 16)
T (nM)	16.9	3.1	14.6	0.20	<1.0 (n = 3)
DHT (ng/g wet weight or mL)	1.9 (n = 8)	0.06 (n = 16)	0.18 (n = 8)	0.012 (n = 16)
DHT (nM)	6.6	0.22	0.63	0.04
Corticosteroids	Hippocampus (freshly isolated)		Plasma		Hippocampus (acute slice)
	Intact	ADX	Intact	ADX
CORT (ng/g wet weight or mL)	128.1 (n = 8)	2.4 (n = 11)	510.3 (n = 8)	0.8 (n = 11)	0.67 (n = 5)
CORT (nM)	369.8	6.9	1472.8	2.3	1.9
DOC (ng/g wet weight or mL)	1.9 (n = 12)	1.9 (n = 23)	1.3 (n = 12)	0.5 (n = 23)
DOC (nM)	5.9	5.8	3.8	1.4

^aHippocampus was homogenized immediately after dissection from a decapitated head. This condition reflects the basal concentration of steroids in hippocampus.

^b“Acute slice” represents hippocampal slices incubated in ACSF for 2 h. Acute slices are usually used for electrophysiological or spinogenesis experiments. Hippocampal steroids are diffused into ACSF and their levels become much lower than that in freshly isolated hippocampus.

^cIntact shows the averaged values from intact and sham-operated rats, because there were no significant differences between these two groups of rats.

^dData are expressed as mean.

^eNumber of animals (i.e., the number of hippocampi).

^fConcentration in nM is calculated using the average volume of 0.14 mL for one whole hippocampus that has 0.14 ± 0.02 g wet weight (n = 86). We assume that tissue having 1 g of wet weight has an approximate volume of 1 mL. Modified from Higo et al. (2011), Hojo et al. (2009), Ooishi et al. (2011).