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

Christopher Brooks Mobley; Carlton D Fox; Brian S Ferguson; Corrie A Pascoe; James C Healy; Jeremy S McAdam; Christopher M Lockwood; Michael D Roberts

doi:10.1186/s12970-015-0076-9

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

J Int Soc Sports Nutr. 2015 Mar 13:12:14. doi: 10.1186/s12970-015-0076-9. eCollection 2015.

Authors

Christopher Brooks Mobley¹, Carlton D Fox¹, Brian S Ferguson¹, Corrie A Pascoe¹, James C Healy¹, Jeremy S McAdam¹, Christopher M Lockwood², Michael D Roberts¹

Affiliations

¹ School of Kinesiology, Molecular and Applied Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL 36849 USA.
² 4Life Research USA, LLC, Sandy, UT USA.

Abstract

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.

Keywords: Egg protein; Hydrolyzed protein; Lipolysis; Muscle protein synthesis; Whey protein.