Fleming M W
J Exp Zool. 1985 Feb;233(2):229-33. doi: 10.1002/jez.1402330209.
Third-stage larvae of the swine parasitic roundworm, Ascaris suum, were grown in stationary multiwell cultures in the presence of synthetic steroid hormones or the HPLC fractions of a steroid extract of adult female reproductive tracts to determine the subsequent effect of these compounds on length of 4th-stage larvae. Log doses of ecdysone, 20-hydroxyecdysone, progesterone, and makisterone standards, from 50 pg/ml to 500 ng/ml, were incubated with larvae for 1 day in RPMI-1640 supplemented with cholesterol. Length measurements were made on 4th-stage larvae after an additional 6 days of incubation. All compounds and extracts had a dose-dependent enhancement on length of these larvae; the partially purified extracts were more potent than their synthetic analogs. All standards and extracts except makisterone showed reduced or no response at higher dose levels. In contrast, makisterone continued to have maximal effect from 500 pg/ml to 500 ng/ml. Short exposure period to the steroid and low concentration were critical to demonstrate enhanced growth in this homologous bioassay.
猪寄生蛔虫——猪蛔虫的三期幼虫，在含有合成甾体激素或成年雌性生殖道甾体提取物的高效液相色谱级分的静态多孔培养物中培养，以确定这些化合物对四期幼虫长度的后续影响。将蜕皮激素、20-羟基蜕皮激素、孕酮和makisterone标准品的对数剂量（从50 pg/ml至500 ng/ml）与幼虫在补充有胆固醇的RPMI-1640中孵育1天。在额外孵育6天后，对四期幼虫进行长度测量。所有化合物和提取物对这些幼虫的长度均有剂量依赖性增强作用；部分纯化的提取物比其合成类似物更有效。除makisterone外，所有标准品和提取物在较高剂量水平下均显示反应降低或无反应。相比之下，makisterone在500 pg/ml至500 ng/ml范围内持续具有最大效应。在这种同源生物测定中，短时间暴露于甾体和低浓度对于证明生长增强至关重要。
