We have investigated the effect of epidermal growth factor (EGF) on collagen metabolism in clonal MC3T3-E1 cells, an osteoblastic cell line derived from newborn mouse calvaria. EGF significantly increased DNA synthesis, but decreased collagen production. We analyzed the amount of total collagen synthesis and degradation products of collagen together with the level of the enzyme responsible for extracellular collagen degradation, to investigate whether the decreased collagen production was due to a decrease in total collagen synthesis or to an increase in collagen degradation. Total collagen synthesis, determined by total hydroxyproline synthesized, was significantly decreased in cells cultured in medium containing EGF, but the amount of collagen degradation products and the level of animal collagenase activity were not increased. Analysis of the collagen type produced by the cells in the absence of EGF showed that 95% of the collagen recovered was type I and 3% was type III. The decreased level of collagen accumulated by cells cultured in the presence of EGF was explained only by the decreased rate of type I collagen synthesis. These results indicate that EGF selectively inhibits type I collagen synthesis in the clonal osteoblastic cell line, MC3T3-E1.

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Prostate glands of adult guinea pigs were stained for nerve growth factor (NGF) and epidermal growth factor (EGF) by immunohistochemical methods. Both NGF and EGF were localized diffusely in the cytoplasm of the glandular epithelial cells, and also in their secretory products. These findings suggest that NGF and EGF are synthesized, stored, and secreted by the glandular epithelial cells of the prostate.

Utsutni N. The dentinogenie ghost eell tutnor. J Oral Pathol 1986: 15: 359-362. An unusual ease of dentinogenic ghost cell tutnor, a peeuliar variant of eaicilying odontogenic cyst, is teported. The tutnor consisted predotninantly of ghost cells with occasional areas of "dentinoid" in close proxitrtity to tnasses of ghost cells. The ptesence of atneloblastotna-like nests of epithelium was eharacteristie of the ptesent ease and they were interpt-eted as a degenerative phenotnenon exhibiting an inductive effect with fortnation of abundant ghost eells, oecurring within a pte-existing atneloblastoma. The tertn "dentinogenic ghost eell tutnor" is etnployed for this unique lesion presented in this report. The literatut-e deseribing the neoplastie potential of the calcifying odontogenie eyst is briefly t-eviewed.