Effect of granulocyte-colony-stimulating factor on serum lactate dehydrogenase levels and isoenzymes in a rabbit model.

We investigated the effect of granulocyte-colony-stimulating factor (G-CSF) alone (G-CSF group, n = 7) or after cyclophosphamide (CY) administration (CY+G-CSF group, n = 7) on serum lactate dehydrogenase (LDH) levels and LDH isoenzymes in a rabbit model. In the G-CSF group, an elevation of LDH (all isoenzymes) which was parallel to a sharp increase in leukocyte counts was noted on the first day of G-CSF administration. Despite the increased leukocyte counts on day 5, LDH levels were decreased. In the CY+G-CSF group, the peak elevation of LDH levels, which was prominent in isoenzymes LDH3, LDH4 and LDH5, occurred on day 5 of G-CSF administration and corresponded to the peak levels of leukocytes. In both groups, there was no correlation between LDH levels and leukocyte counts. Our data suggest that an elevation of LDH during the administration of G-CSF may be related to the differentiation of myeloid progenitors. Copyright 2002 S. Karger AG, Basel