Journal of Dental Research, Vol 56, 509-517, Copyright © 1977 by International & American Associations for Dental Research Online Journals
Influence of growth hormone and thyroxine on endochondral osteogenesis in the mandibular condyle and proximal tibial epiphysis
W. E. Hoskins and C. W. Asling
Interrelationships of growth hormone and thyroxine effects on endochondral
osteogenesis have been investigated. Evidence is offered that thyroxine
augments the effect of growth hormone on the mandibular condyle just as at
other osteogenetic centers, for example proximal tibial epiphysis in
hypophysectomized rats. This contrasts with previous reports of a unique
thyroxine antagonism to the effect of growth hormone on condylar
development. In a further study on tibial epiphysis, special attention was
given to assure absence of the endogenous thyroid hormone by adding
thyroidectomy to hypophysectomy and reducing the possibility of thyroteopin
residues in growth hormone. By histochemical tests, the responses of both
calcified and noncalcified regions of the epiphyseal cartilage plate were
measured. Graded growth hormone doses stimulated graded response in a
noncalcified region. Thyroxine augmented this response eightfold. The width
of the calcified region of the plate did not vary with treatment.
