ABSTRACT
Most parasites have a number of unusual features in their metabolic pathways (Bryant and Behm, 1989), and Leishmania sp. are no exception. Examples are the compartmentation of glucose utilization (see Chapter 11), the role of pCO2 and pO2 in metabolic regulation, the formation of D-lactate, and the metabolism of alanine and its role in osmoregulation. In this brief review we focus on the current understanding of some of these unusual features of Leishmania metabolism. Of necessity, most of these studies have been performed on promastigotes, since it was relatively difficult to obtain sufficient quantities of either the infective metacyclic forms or of amastigotes for metabolic studies. The recent development of methods to obtain sufficient quantities of the metacyclic stages of L. major (Sacks et al., 1985), and to grow axenic cultures of the amastigote form of L. panamensis (Eperon and McMahon-Pratt, 1989) now make it feasible to undertake metabolic studies on metacyclics and amastigotes such as those that have been performed on promastigotes, and thus to increase our understanding of the metabolic changes that occur as the parasites change their form and habitat.
