Depletion of delta 9 desaturase (EC 1.14.99.5) activity in lactating rat during protein restriction.
The effects of protein restriction on the activity of delta9 desaturase (EC 1.14.99.5) were investigated in lactating rats. A control group was fed a balanced diet (20% casein) for 14 days, whereas the experimental groups were fed a low-protein diet (8% casein), supplemented with or without L-methionine (0.4%), for 14 days. The enzyme activity was measured by incubations of hepatic microsomal pellets with (1-14C) stearic acid. Results showed a decreased delta9 desaturase activity, after 2,7 and 14 days of depleted diet, of -50, -40 and -33% respectively, compared with control. The supplementation of the low-protein diet with 0.4% methionine, which favours food consumption as well as growth, did not improve the altered delta9 desaturase activity. Our data evidenced that delta9 desaturase activity is depleted by protein restriction during lactation, when the protein needs are high for the biosynthesis of animal tissues. This change has to be considered as a sign of depressed delta9 desaturase biosynthesis or modifications of enzymatic properties, or both.
Chanussot
B
B
UPRES Lipides et Nutrition, Faculté des Sciences Mirande, Université de Bourgogne, Dijon, France.
Leclerc
J
J
Narce
M
M
Poisson
J P
JP
D000818:Animals; D001835:Body Weight / Q000502:physiology; D002364:Caseins / Q000008:administration & dosage; D018753:Diet, Protein-Restricted / Q000009:adverse effects*; D004435:Eating / Q000502:physiology; D004789:Enzyme Activation / Q000502:physiology; D044943:Fatty Acid Desaturases / Q000096:biosynthesis / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D007774:Lactation / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000502:physiology; D008715:Methionine / Q000008:administration & dosage; D009929:Organ Size / Q000502:physiology; D010743:Phospholipids / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013230:Stearoyl-CoA Desaturase
D002364:Caseins; D005227:Fatty Acids; D010743:Phospholipids; D008715:Methionine; D044943:Fatty Acid Desaturases; D013230:Stearoyl-CoA Desaturase; C029627:delta-9 fatty acid desaturase