Fibroblast growth factor 21 mediates specific glucagon actions

Glucagon, an essential regulator of glucose homeostasis, also modulates lipid metabolism and promotes weight loss, as reflected by the wasting observed in glucagonoma patients. Recently, coagonist peptides that include glucagon agonism have emerged as promising therapeutic candidates for the treatment of obesity and diabetes. We developed a novel stable and soluble glucagon receptor (GcgR) agonist, which allowed for in vivo dissection of glucagon action. As expected, chronic GcgR agonism in mice resulted in hyperglycemia and lower body fat and plasma cholesterol. Notably, GcgR activation also raised hepatic expression and circulating levels of fibroblast growth factor 21 (FGF21). This effect was retained in isolated primary hepatocytes from wild-type (WT) mice, but not GcgR knockout mice. We confirmed this link in healthy human volunteers, where injection of natural glucagon increased plasma FGF21 within hours. Functional relevance was evidenced in mice with genetic deletion of FGF21, where GcgR activation failed to induce the body weight loss and lipid metabolism changes observed in WT mice. Taken together, these data reveal for the first time that glucagon controls glucose, energy, and lipid metabolism at least in part via FGF21-dependent pathways.

Periosteal chondroma: a review of the literature and case report

Periosteal chondroma is a benign and relatively rare cartilaginous tumor. The authors discuss a case with some typical and some atypical characteristics. The differential diagnosis is important because of its resemblance to chondrosarcoma.

Ankle tenography: a key to unexplained symptomatology. Part I: Normal tenographic anatomy

Fifty cadaver ankles were examined with ankle tenography. The normal tenographic appearance of the peroneus longus and brevis, posterior tibial, flexor digitorum longus, flexor hallucis longus, anterior tibialis, extensor hallucis longus, and extensor digitorum longus tendons and sheaths are described and illustrated for clinical reference. The baseline measurements and demonstration of the normal radiographic appearance of these tendons should assist in the evaluation of hindfoot foot disability and ankle pain.