High usage of the synthetic glucocorticoids (GCs) has led to significant presence of this pharmaceutical group in surface waters where it can affect non-target organisms such as fish. Assessment of a fish's metabolism and swimming performance provide reliable sub-lethal measures of effects of GCs on oxygen-requiring processes and ability to swim. In this study, we determined time-dependent (7, 14 and 21 days) effects of the synthetic GC prednisone (1 μg L⁻¹) on sheepshead minnow (SHM) (Cyprinodon variegatus). Standard (SMR), routine (RMR) and maximum (MMR) metabolic rate, metabolic scope (MS), excess post-exercise oxygen consumption (EPOC), cost of transport (COT) and critical swimming speed (U_crit) were determined. Twenty-one days exposure to prednisone resulted in significantly higher SMR, RMR, MMR, MS, EPOC and COT compared with 7d and 14d prednisone fish. However, U_crit was not significantly different between prednisone and solvent control exposed fish (within 7d, 14d, 21d groups). SMR, RMR and MMR were lower in the 7d and 14d prednisone exposed fish compared with their solvent control groups. In contrast, SMR, RMR and MMR were all significantly higher in the 21d prednisone exposed fish compared with solvent control. EPOC was significantly higher in 14d prednisone exposed fish and trending higher in 21d and 7d prednisone exposed fish compared with their solvent controls. EPOC was significantly higher in 21d compared with 7d prednisone exposed fish. A significantly higher COT was seen in the 21d compared with 7d and 14d prednisone fish. Collectively, this study showed time-dependent effects of prednisone on SHM metabolism and swimming performance.

合成糖皮质激素 (GC) 的大量使用导致该药物组在地表水中大量存在，在那里它可以影响非目标生物，如鱼类。对鱼的新陈代谢和游泳性能的评估提供了可靠的亚致死测量 GC 对需氧过程和游泳能力的影响。在这项研究中，我们确定了合成 GC 泼尼松 (1 μg L ^-1 ) 对羊头鲦鱼 (SHM) ( Cyprinodon variegatus ) 的时间依赖性（7、14 和 21 天）影响。标准 (SMR)、常规 (RMR) 和最大 (MMR) 代谢率、代谢范围 (MS)、运动后过量耗氧量 (EPOC)、运输成本 (COT) 和临界游泳速度 (U _crit)) 确定。与 7 天和 14 天泼尼松鱼相比，暴露于泼尼松 21 天导致 SMR、RMR、MMR、MS、EPOC 和 COT 显着升高。然而，U_暴击泼尼松和溶剂对照暴露的鱼（在 7d、14d、21d 组内）之间没有显着差异。与溶剂对照组相比，暴露于泼尼松 7 天和 14 天的鱼的 SMR、RMR 和 MMR 较低。相比之下，与溶剂对照相比，暴露于泼尼松 21 天的鱼的 SMR、RMR 和 MMR 均显着更高。与溶剂对照组相比，14 天泼尼松暴露鱼的 EPOC 显着更高，21 天和 7 天泼尼松暴露鱼的 EPOC 呈更高趋势。与暴露于泼尼松 7 天的鱼相比，21 天的 EPOC 显着更高。与第 7 天和第 14 天泼尼松鱼相比，第 21 天的 COT 显着更高。总的来说，这项研究显示了泼尼松对 SHM 代谢和游泳表现的时间依赖性影响。