Intrarenal distribution of ampicillin in the healthy and the infected rat kidney: a comparison of methods.

The ampicillin concentration in the cortex of the normal and the infected rat kidney was determined by means of three different methods: tissue homogenate analysis, renal lymph analysis, and autoradiography. Both tissue homogenate analysis and autoradiography revealed that the cortical ampicillin concentration was about five times as high as the serum concentration. Renal lymph analysis disclosed that the ampicillin concentration in this fluid amounted to about 93% of the serum concentration. The discrepancy between these results can be explained on the basis of the binding of ampicillin to cellular components in the cortex. The results of the study of ampicillin distribution in infected rat kidneys with the aid of tissue homogenate analysis and autoradiography indicate that the ampicillin concentration was lower in the affected than in the intact tissue. Renal lymph analysis showed that the ampicillin concentration in the lymph was not affected by the presence of the infection. Quantitative autoradiography demonstrated that the ampicillin concentration in the cortical foci of infection was of the same order of magnitude as the serum concentration. For this kind of study autoradiography together with lymph analysis are recommended.