Cyclic nucleotide and prostaglandin F2 alpha contents of otosclerotic auditory ossicles.

We found that the cyclic-adenosine-3',5'-monophosphate (cAMP) contents of otosclerotic human ossicles were 40-50 times greater than basal levels. Cyclic-guanosine-3',5'-monophosphate (cGMP) levels were also found to be greater than in physiological conditions, but lower than in cortical bone. These findings suggest the extensive participation of these nucleotide coenzymes in effector cells during the process of bone resorption. This emphasizes the role of bone-resorbing cells in this process as well as the probable osteoclast progenitor role of vascular endothelial cells and their enhanced activity for differentiation. At the same time, the absence of prostaglandin F2 alpha content in the otosclerotic bone analyzed appears to exclude cartilage remnants as a source for inducing the changes in remodelling that occur.