Tumor necrosis factor (TNF) has been reported to be identical to "cachectin," a monokine which we have previously proposed as a mediator of the enhanced catabolism observed in patients or animals responding to various invasive stimuli such as infections. Detailed quantitative studies were conducted on the effects of TNF on fatty acid metabolism in 3T3-L1 cells in order to explore the extent of the catabolic effects exerted by TNF compared with those by the crude cachectin. 3T3-L1 adipocytes responded to recombinant human TNF, showing a decrease in LPL activity and an increase in intracellular lipolysis. When TNF in the crude cachectin preparation was completely neutralized with anti-TNF antibody, about 75% of LPL suppression activity in the crude cachectin was absorbed, indicating that most of the mediator responsible for LPL suppression in the crude preparation is TNF. In contrast to the above effect on LPL, TNF markedly increased the lipolysis of stored fat in the cells. The effect on LPL was observed as early as 2 h after the addition of TNF, but enhancement of lipolysis required a time lag of at least 3 h before any increase of glycerol release became apparent. The effective concentrations of TNF for the stimulation of lipolysis were much higher (2.5 to 49 nM) than those for LPL suppression (50 pM to 50 nM), but both were in the same range as the concentration required for tumoricidal effect. These results demonstrate that cachectin is synonymous with TNF and that it plays an important role in the pathophysiology of deranged lipid metabolism through both suppression of LPL and enhancement of lipolysis in patients coping with invasive conditions such as infections.

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in irradiations with bremsstrahlung having maximum end-point energies up to 1200 MeV were measured by γ-ray spectrometry ( 7 Be, 22 Na, 24 Na and 28 Mg) and accelerator mass spectrometry ( 10 Be). The yields of heavier fragments, 39 Cl,43, 44m, 44g,46,47, 48 Sc, 59 Fe,and 56,57,58,60 Co, were also measured by γ-ray spectrometry in order to survey the relative contribution of fragmentation to spallation and/or fission in the mass yield curves. A distinct difference of the target massdependence of these yields has made it possible to disentangle the contributions of photospallation and photofragmentation processes. It was found that the neutron-to-proton ratios of targets strongly affect the formation of the nuclei by fragmentation as revealed in the yields of the isotopic pairs as well as of the single isotopes. The photon results were compared with those of proton-induced reactions, and no clear effect due to the difference of the initial interactions of photons and protons with nuclei was found in the fragment yields.