Undernutrition decreases serine palmitoyltransferase activity in developing rat hypothalamus

Background/Aims: Undernutrition reduces the hypothalamic ganglioside concen tration; This may be attributed to some modifications in the contents of pr ecursors of sphingolipid biosynthesis in undernourished rats. The present s tudy evaluated the serine palmitoyl transferase activity (SPT,: EC 2.3.1.50 ) during the development of the rat hypothalamus. This work also shows the L-[3-C-14]serine metabolic labeling of hypothalamic sphingolipids in normal and undernourished rats at weaning. Methods: The SPT activity was determin ed in microsomal fractions obtained from the hypothalamus of normal rats (d iet: 25% protein) and pre- and postnatally undernourished rats (diet: 8% pr otein since pregnancy) at: 21 days of gestational age and at 7, 14, and 21 days of postnatal life. Results:The enzymatic activity was lower in the hyp othalamus of undernourished than in the hypothalamus of control rats since the 7th postnatal day. Incorporation of the precursor L-[-3(14)C]serine int o sphingolipid fraction was lower in the hypothalamus of undernourished rat s than in the hypothalamus of control rats on the 21st postnatal day which coincided with the age of the highest difference in SPT activity between no rmal and undernourished rats. Conclusion: These results indicate that under nutrition reduces the biosynthesis of the main sphingolipids during the per iod of brain growth spurt.