Undernutrition decreases serine palmitoyltransferase activity in developing rat hypothalamus.
OBJECTIVE
Undernutrition reduces the hypothalamic ganglioside concentration. This may be attributed to some modifications in the contents of precursors of sphingolipid biosynthesis in undernourished rats. The present study 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-(14)C]serine metabolic labeling of hypothalamic sphingolipids in normal and undernourished rats at weaning.


METHODS
The SPT activity was determined in microsomal fractions obtained from the hypothalamus of normal rats (diet: 25% protein) and pre- and postnatally undernourished rats (diet: 8% protein 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 hypothalamus of undernourished than in the hypothalamus of control rats since the 7th postnatal day. Incorporation of the precursor L-[3-(14)C]serine into sphingolipid fraction was lower in the hypothalamus of undernourished rats 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 normal and undernourished rats.


CONCLUSIONS
These results indicate that undernutrition reduces the biosynthesis of the main sphingolipids during the period of brain growth spurt.
Rotta
L N
LN
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Da Silva
C G
CG
Perry
M L
ML
Trindade
V M
VM
D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD; D001345:Autoradiography; D002250:Carbon Radioisotopes; D005260:Female; D005732:Gangliosides / Q000378:metabolism; D005963:Glucosylceramides / Q000378:metabolism; D007031:Hypothalamus / Q000201:enzymology* / Q000254:growth & development*; D007790:Lactosylceramides / Q000378:metabolism; D009748:Nutrition Disorders / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000378:metabolism; D051102:Serine C-Palmitoyltransferase; D013109:Sphingomyelins / Q000378:metabolism
D015703:Antigens, CD; D002250:Carbon Radioisotopes; D005732:Gangliosides; D005963:Glucosylceramides; D007790:Lactosylceramides; D013109:Sphingomyelins; D012694:Serine; C009744:CDw17 antigen; D000217:Acyltransferases; D051102:Serine C-Palmitoyltransferase