Vol. 86, Issue 3, 852-859, March 1999
Hormone-related, muscle-specific changes in protein metabolism
and fiber type profile after faba bean intake
Gema
Frühbeck1,
A.
Cristina
Villaro2,
Ignacio
Monreal3, and
Santiago
Santidrián1
Departments of 1 Human
Physiology and 2 Histology, School
of Medicine, and 3 Laboratory
of Biochemistry, Universitary Clinic of Navarra, University of Navarra,
31080 Pamplona, Spain
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.
soleus; extensor digitorum longus; Vicia faba
L.
