Transfer of dietary sulphamonomethoxine and sulphadimethoxine into various tissues of laying hens.

1. Sulphamonomethoxine (SMM) or sulphadimethoxine (SDM) were fed to laying hens at a dietary concentration of 400 mg/kg. Concentrations (mg/kg) of SMM and SDM in the blood, kidney, liver, ovary, muscle and adipose tissue, collected at 4, 8, 16 and 24 h after the start of feeding, were determined by HPLC. 2. The relationships between the sulphonamide concentrations (mg/kg) in the tissues and times (h) after the start of the feeding were analysed statistically. 3. Dietary SMM and SDM were transferred throughout the whole body, and concentrations in all tissues became constant 8 h after the start of feeding. 4. Among the 6 tissues examined the constant values (mg/kg) of both SMM and SDM were highest in the kidney and were lowest in adipose tissue. 5. With the exception of adipose tissue, the values of SDM in the tissues were statistically greater than those of SMM.