LIPOGENESIS IN RAT-TISSUES FOLLOWING CARBOHYDRATE REFEEDING - SPLEEN LIPOGENESIS IS MODULATED BY INSULIN

Intraperitoneal administration of [1,2-C-14]-acetate to Wistar rats wa s used to assess tissue lipogenic rates after estimating the incorpora tion of the label into the tissular lipid fractions. Refeeding the ani mals with glucose (after an overnight fast) induced an increase in whi te adipose tissue (4.5 fold), liver (4.1 fold), small intestine (1.9 f old), carcass (2.9 fold) and spleen (3.7 fold) lipogenesis (expressed as the radioactivity present in the lipid fraction corrected by the pl asma circulating radioactivity). No changes were found following refee ding in either brain or brown adipose tissue. Administration of mannoh eptulose (an inhibitor of insulin secretion) to refed rats completely abolished the increased lipogenesis in white adipose tissue, liver, ca rcass, spleen and small intestine, thus suggesting that insulin secret ion is involved in this phenomenon. This is the first report showing t hat spleen lipogenesis may be modulated by refeeding via insulin secre tion and suggests an important role of this organ on the in vivo lipog enic response of the organism after carbohydrate refeeding.