Possible role for glucagon in the control of Paget's disease of bone.

Paget's disease of bone is characterised by overactive osteoclasts that resorb bone at a higher rate than normal. Osteoblasts attempt to repair the damage by laying down new bone which in turn is resorbed leaving a chaotic pattern of lytic and dense sclerotic bone behind. Deformed bone enlarges, becomes vascularised, bends and fractures. No bone is exempt but the skull, pelvis, vertebrae and long bones are commonly affected. Pressure from pagetic bone impinges on the auditory, facial, optic, trigeminal nerves and the spinal cord, risking paraplegia or quadriplegia. Vascular complications include cardiac failure and vertebrobasilar insufficiency. Serum alkaline phosphatase and urine N-telopeptide were used to assess response to treatment with porcine, salmon and human calcitonins, glucagon and bisphonates given alone or in combination. Glucagon has few side effects and controls the disease very rapidly. It can be given alone but because remissions last a few months, repeat courses may be necessary to achieve a long-term permanent quiescent bone state. If complete disease remission is not achieved with the hormone alone, an oral or intravenous bisphosphonate is given at the end of glucagon treatment. Other options are a second-generation bisphosphonate given orally to patients who decline parenteral medication. It remains to be seen whether glucagon affects other bone disorders.