Effects of protein type and composition on postprandial markers of skeletal muscle anabolism,adipose tissue lipolysis,and hypothalamic gene expression

Background: we examined the acute effects of different dietary protein sources (0.19 g,dissolved in 1 ml of water) on skeletal muscle,adipose tissue and hypothalamic satiety-related markers in fasted,male wistar rats (~250 g). methods: oral gavage treatments included: a) whey protein concentrate (wpc,n = 15); b) 70:30 hydrolyzed whey-to-hydrolyzed egg albumin (70 w/30e,n = 15); c) 50 w/50e (n = 15); d) 30 w/70e (n = 15); and e) 1 ml of water with no protein as a fasting control (ctl,n = 14). results: skeletal muscle analyses revealed that compared to ctl: a) phosphorylated (p) markers of mtor signaling [p-mtor (ser2481) and p-rps6 (ser235/236)] were elevated 2-4-fold in all protein groups 90 min post-treatment (p < 0.05); b) wpc and 70 w/30e increased muscle protein synthesis (mps) 104% and 74% 180 min post-treatment,respectively (p < 0.05); and c) 70 w/30e increased p-ampkα (thr172) 90 and 180-min post-treatment as well as pgc-1α mrna 90 min post-treatment. subcutaneous (sq) and omental fat (omat) analyses revealed: a) 70 w/30 w increased sq fat phosphorylated hormone-sensitive lipase [p-hsl (ser563)] 3.1-fold versus ctl and a 1.9-4.4-fold change versus all other test proteins 180 min post-treatment (p < 0.05); and b) wpc,70 w/30e and 50 w/50e increased omat p-hsl 3.8-6.5-fold 180 min post-treatment versus ctl (p < 0.05). 70 w/30e and 30 w/70e increased hypothalamic pomc mrna 90 min post-treatment versus ctl rats suggesting a satiety-related response may have occurred in the former groups. however,there was a compensatory increase in orexigenic agrp mrna in the 70 w/30e group 90 min post-treatment versus ctl rats,and there was a compensatory increase in orexigenic npy mrna in the 30 w/70e group 90 min post-treatment versus ctl rats. conclusions: higher amounts of whey versus egg protein stimulate the greatest post-treatment anabolic skeletal muscle response,though test proteins with higher amounts of wph more favorably affected post-treatment markers related to adipose tissue lipolysis. © 2015 mobley et al.