Development of the "activated" high resolution 1H MR spectrum in murine T cells and B cells occurs in G1 phase of the cell cycle.

T and B lymphocytes stimulated with mitogens develop 1H MR spectra characteristic of triglycerides in an isotropic environment. These distinctive signals, which are also observed in malignant cells, cannot be suppressed by compounds which inhibit progression through the cell cycle. Cellular proliferation is thus not essential for the development and maintenance of high resolution lipid spectra in activated cells.