GPC4 and metabolic syndrome: As is well known, adipose tissue and skeletal muscle contribute to systemic levels of glypican-4 [3], which may partly explain the increase in serum levels of this adipokine we noted only in the group of women without MetS, as we observed a loss of body fat mass after 28 days of physical activity in our MetS group, but not in the CONTR group, especially since only in the CONTR group did we observe an increase in arm circumference at the end of the study.