Table 1.
Basal serum levels of GABAergic neuroactive steroids across species.
| Rats | C57BL/6J Mice | DBA/2J Mice | Monkeys | Humans | |
|---|---|---|---|---|---|
| Pregnenolone | 164.9 ± 55.3 (8/9) | 48.8 ± 6.0 (7/7) | 27.6 ± 8.3 (6/7) | 944.8 ± 287.1 (10/11) | 296.9 ± 28.9 (8/8) |
| 3α,5α-THP | 111.3 ± 12.2 (9/10) | 1043 ± 91.3 (14/14) | 455.2 ± 63.4 (8/8) | 59.8 ± 14.7 (11/11) | 124.8 ± 12.2 (8/8) |
| 3α,5β-THP | 116.5 ± 43.4 (4/10) | n.d. | n.d. | 19.3 ± 7.4 (11/11) | 109.2 ± 4.5 (8/8) |
| 3α,5α-THDOC | 82.8 ± 16.5 (6/10) | 589.4 ± 76.0 (14/14) | 393.6 ± 64.5 (7/8) | 27.5 ± 2.4 (10/10) | 63.0 ± 21.6 (8/8) |
| 3α,5β-THDOC | n.d. | n.d. | n.d. | n.d. | n.d. |
| 3α,5α-Androsterone | 99.2 ± 9.1 (10/10) | 61.3 ± 7.6 (14/14) | 38.7 ± 8.9 (7/8) | 103.6 ± 14.3 (11/11) | 97.3 ± 12.0 (8/8) |
| 3α,5β-Androsterone | 103.5 ± 9.3 (10/10) | n.d. | n.d. | n.d. | 177.5 ± 88.7 (8/8) |
| 3α,5α-Androstandiol | 115.0 ± 21.8 (10/10) | 72.2 ± 2.8 (14/14) | 72.5 ± 8.6 (8/8) | 4.7 ± 1.9 (8/11) | 34.9 ± 4.3 (8/8) |
| 3α,5β-Androstandiol | n.d. | 50.5 ± 1.9 (11/14) | 50.1 ± 4.6 (5/8) | n.d. | 23.4 ± 1.4 (8/8) |
Serum GABAergic neuroactive steroids were measured by GC-MS as previously described (Porcu et al., 2009). Levels are expressed as pg/ml and are average ± SEM. The n values for each group are reported in parentheses. The limit of detection for the GC-MS assay was 2 pg/ml for 3α,5β-THP, 3α,5α-THDOC, 3α,5β-THDOC, 3α,5β-androsterone, 3α,5α-androstandiol, 3α,5β-androstandiol, and 10 pg/ml for 3α,5α-THP, 3α,5α-androsterone and pregnenolone.