ALTERED PHOSPHORYLATION STATUS, PHOSPHOLIPID-METABOLISM AND GLUCONEOGENESIS IN THE HOST LIVER OF RATS WITH PROSTATE-CANCER - A P-31 MAGNETIC-RESONANCE SPECTROSCOPY STUDY

P-31 magnetic resonance spectroscopy (MRS) in vivo and in vitro was us ed to study modulation of host liver (HL) metabolism in rats bearing t he MAT-LyLu variant of the Dunning prostate tumour. Animals were inocu lated either with 10(6) or 10(7) MAT-LyLu cells, or with saline to ser ve as controls. Carcass weight in tumour-bearing (TB) animals decrease d despite similar food and water intake in both groups. Absence of met astatic tumour cells from HL of all TB animals was confirmed by histol ogical examination. Twenty-one days after inoculation, P-31 MRS showed a 2.5-fold increase in [Pi]/[ATP] ratios in HL in vivo (P<0.001) whic h was confirmed by P-31 MRS of liver extracts in vitro (P<0.005). Phos phodiester to ATP ratios were significantly increased (P <0.05) in HL in vivo, but absolute PDE levels were similar in both groups. Phosphom onoester to ATP ratios did not change, although absolute phosphomonoes ter levels in HL were reduced by -41% (not significant). In HL extract s in vitro, sharp reductions in the levels of glucose-6-phosphate (P<0 .05), fructose-6-phosphate (P=0.05), phosphocholine (P<0.001), glycero phosphocholine (P<0.001), and glycerophosphoethanolamine (P<0.001) wer e observed. Electron microscopy revealed increased amounts and altered distribution of rough endoplasmic reticulum in HL. These findings sho w that experimental prostate cancer significantly affects hepatic phos phorylation status, phospholipid metabolism, and gluconeogenesis in th e host animal, and demonstrate the value of combined MRS in vivo and i n vitro in monitoring HL metabolism in cancer.