Dietary amino acids fed in free form and as protein components do not differently affect postprandial plasma insulin, glucagon, growth hormone and corticosterone responses in rats.
This study examined, whether the postprandial fate of dietary amino acids from different amino acid sources is regulated by the responses of insulin, glucagon, corticosterone and growth hormone (GH). Male Wistar rats were cannulated in the vena jugularis and assigned to dietary groups. The diets contained 21% casein or the same amino acids in free form. In the free amino acid diets, methionine level was varied between the groups. The feed was supplied in two distinct meals. In previous experiments it was established that oxidative amino acid losses of the free amino acid diets and protein diets were different. After 3 weeks on those diets, it appeared that the differences in postprandial oxidative losses had been diminished. GH was measured every 12 min, from 144 min before the start of the experimental meal over the following 144 min. Insulin and corticosterone were measured six times from the start of the meal until 270 min after the meal. No differences have been observed between the hormonal responses to both meals at day 5 and at day 26. In conclusion, it has been found that the differences in the oxidative losses between protein and free amino acid meals are not mediated by the combined action of the insulin, glucagon, corticosterone and GH. Postprandial catabolism of amino acids is most probably regulated by substrate induction.
Nolles
J A
JA
Human and Animal Physiology Group, Wageningen Institute of Animal Sciences (WIAS) and Research Center, Haarweg 10, NL-6709 PJ Wageningen, The Netherlands. jelmer.nolles@wur.nl
Van Straten
E M E
EM
Bremer
B I
BI
Koopmanschap
R E
RE
Verstegen
M W A
MW
Schreurs
V V A M
VV
D000596:Amino Acids / Q000008:administration & dosage*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D019540:Area Under Curve; D003345:Corticosterone / Q000097:blood*; D004734:Energy Metabolism / Q000502:physiology*; D005934:Glucagon / Q000097:blood*; D013006:Growth Hormone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D008297:Male; D019518:Postprandial Period; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D015430:Weight Gain / Q000187:drug effects
D000596:Amino Acids; D007328:Insulin; D013006:Growth Hormone; D005934:Glucagon; D003345:Corticosterone