Fluctuations in rat liver alanine-amino-transferase activity during experimental nippostrongylosis

The activity of the gluconeogenic enzyme, alanine-amino-transferase (ALT), in a preparation from the liver of rats was studied by means of an in vitro assay throughout the course of a primary infection of Nippostrongylus brasiliensis, established by a subcutaneous injection of approximately 4000 3rd-stage larvae. The activity was measured on days 1-14 p.i. in both uninfected and infected rats and a marked pattern in the enzyme's activity was observed. In infected rats, the activity increased from 1.46 +/- 0.19 U/g liver on day 1 p.i. to a peak on day 4 p.i. of 10.75 +/- 1.62 U/g liver, then decreased to a trough of 0.44 +/- 0.18 U/g liver on day 10 p.i. before returning to original levels by day 14 p.i., by which time the infection had been largely eliminated. In uninfected rats the activity of the liver enzyme remained constant throughout this period with a value of 2.54 +/- 0.12 U/g liver. The activity of the enzyme in vitro was found to be related to the size of the inoculum on days 4 and 10 p.i. It was proposed that these observations could be due to either (1) a direct effect of the parasite, or (2) a consequence of the host immune response to the infection. In order to investigate the second proposition more fully, liver ALT activity was investigated by in vitro assay on selected days p.i. in rats experiencing a secondary N. brasiliensis infection.(ABSTRACT TRUNCATED AT 250 WORDS)