Eleven previously uncharacterized steroids, along with three analogs were isolated from Aglaia lawii leaves. Their structures were definitely characterized by the methods of NMR, MS, IR, ECD and X-ray crystallography study. Among these unreported compounds, 3-epi-dyscusin C, 3-epi-lansisterone E and (Z)-2α-hydroxyaglawone were C-21 pregnane steroids incorporating a highly oxygenated ring A, while others were Δ⁵-3β-hydroxy-7-<em>ketosteroids</em> bearing different ring D and C-<em>17</em> aliphatic chains. All isolates were evaluated for nitric oxide (NO) inhibitory activities. 3-Epi-dyscusin C, 3-epi-lansisterone E, (Z)-2α-hydroxyaglawone and <em>17</em>(20)E-dyscusin B showed significant anti-inflammatory activities with IC₅₀ values of NO inhibition less than 10 μM (in the range from 4.47 ± 0.36 to 7.67 ± 0.46 μM).

Keywords: Aglaia lawii; Anti-inflammatory; Meliaceae; Nitric oxide; Steroids.

<em>Ketosteroids</em> were determined colorimetrically in samples of 24-hour urine from sows, ten days after service. Pregnancy was diagnosed by injection of the "Gravignost-swine" preparation in eight sows. Significant differences between the <em>17</em>-<em>ketosteroid</em> excretion on non-pregnant sows were revealed by the excretion in 24-hour urine, but not by urinary concentration expressed in mg per litre. Injection of "Gravignost" had no effect on <em>17</em>-<em>ketosteroid</em> values. In pregnant sows the urinary concentration of <em>17</em>-<em>ketosteroids</em> was inversely proportional to daily urine volume, and there was also a significant correlation between urine volume and <em>17</em>-<em>ketosteroid</em> excretion expressed in mg per 24 hours. The method used for determining urinary <em>ketosteroids</em> was sufficiently reliable and simple to be used for routine testing.