Hormone-related, muscle-specific changes in protein metabolism and fiber type profile after faba bean intake

Abstract

Male growing Wistar rats were fed, over 15 days, isoenergetic (16.72 +/- 0.49 MJ) and isoproteic (11%) diets containing either lactalbumin or raw Vicia faba L. (Vf) as the sole source of protein. Compared with pair-fed controls (PF), soleus muscles of Vf-fed rats showed increased (P < 0.05) synthesis and breakdown rates. In addition, the soleus of Vf-fed rats displayed a decrease (P < 0.05) in type I and an increase (P < 0.01) in type IIc fibers compared with that of PF animals. On the contrary, extensor digitorum longus muscles of both Vf-fed and PF rats showed an increase (P < 0.01) in type I and a reduction (P < 0.05) in type IIb fibers together with a decrease (P < 0.05) in the cross-sectional area of the latter fibers. Vf-fed rats exhibited a significant decrease in serum insulin (P < 0.05) and thyrotropin (P < 0.01) levels, together with an increase in plasma glucagon (P < 0.05) and 3,5,3'-triiodothyronine (P < 0.01) concentrations, compared with the PF group. Both Vf-fed and PF rats experienced an increase in corticosterone concentrations (P < 0.01 vs. control; P < 0.05 vs. PF). The muscle-specific changes in both protein metabolism and fiber type composition may partly depend on the hormonal changes that were observed after Vf intake.

Differential Effects of Cooked Common Bean (<i>Phaseolus vulgaris</i>) and Lentil (<i>Lens esculenta puyensis</i>) Feeding on Protein and Nucleic Acid Contents in Intestines, Liver and Muscles in Rats

“…However, the effect of legume feeding on DNA levels seems to depend on the metabolic type of muscle since they were signifi cantly lower in gastrocnemius muscle (fast-twitch oxidative glycolytic) of the bean-or lentil-fed rats than in the controls, but this did not occur in the soleus muscle (slow oxidative muscle). A similar difference in the responses of different metabolic types of muscles to legume feeding has already been observed for protein and RNA contents when comparing the effects of raw Vicia faba feeding on soleus and on extensor digitorum longus (fast-twitch glycolytic) muscles in rats [42] . In that experiment, the difference between muscle responses was related to modifi cations of the muscle fi bre composition that appeared to be induced by hormonal changes resulting from legume feeding.…”

Differential Effects of Cooked Beans and Cooked Lentils on Protein Metabolism in Intestine and Muscle in Growing Rats

“…It has been also reported that bean constituents infl uence and modulate the endocrine status [21] , which can change protein metabolism. Frühbeck et al [41] showed that plasma glucagon levels increased in rats fed diets containing V. faba and that there were signifi cant negative correlations between glucagon concentration and muscle protein content as well as fractional protein synthesis rate. Also the other hormones (T 3 , T 4 , insulin, corticosterone) were affected by inclusion of V. faba [41] or raw and extruded peas [35] in the diet.…”

“…Frühbeck et al [41] showed that plasma glucagon levels increased in rats fed diets containing V. faba and that there were signifi cant negative correlations between glucagon concentration and muscle protein content as well as fractional protein synthesis rate. Also the other hormones (T 3 , T 4 , insulin, corticosterone) were affected by inclusion of V. faba [41] or raw and extruded peas [35] in the diet. However, those differences were abolished after supplementation of the diets with amino acids, except for corticosterone, which remained high [35] .…”

Differential effect of lentil feeding on proteosynthesis rates in the large intestine, liver and muscle of rats1

“…In liver, raw faba bean intake increased protein synthesis in rats [20] whereas enteral infusion of soybean protein decreased it in pigs [19]. Raw faba bean intake decreased protein synthesis rate in gastrocnemius [20], had no effect on extensor digitorum longus and increased it in soleus [21]. Enteral infusion of soybean protein resulted in higher aminoacid uptake by hind legs in pigs than casein infusion [19].…”