Ultrastructure of cementogenesis as affected by growth hormone in the molar periodontium of the hypophysectomized rat

Abstract

To document the effect of hypophysectomy and growth hormone replacement on the ultrastructure of cementogenesis in the developing rat third molar, 12 female Wistar rats were randomly allocated to normal control, hypophysectomized or hypophysectomized plus human growth hormone (for 10 days) treatment groups. The results of this study by electron and light microscopy and morphometry have shown that qualitative and quantitative changes occur in the organelles of cementoblasts forming cellular cementum as a result of hypophysectomy and growth hormone replacement. After hypophysectomy, the changes of less prominent nucleoli and nuclear pores, less prominent Golgi apparatuses and decreased endoplasmic reticulum can be interpreted as diminished cementum matrix biosynthesis--an interpretation that can be confirmed morphometrically by less cellular cementum formation. Growth hormone replacement for 10 days reactivates protein synthesis and cementogenesis as evidenced by ultrastructural changes in cementoblasts and a greater production of cementum.

Comparison of the validity of three dental methods for the estimation of age at death

“…If the count of cementum annulations is added to the toothspecific eruption age, the result is an estimate of the chronological age. A possible explanation for the layered organization of human cementum is the fact that growth hormone affects cementogenesis [10][11][12] which could be influenced by environmental factors such as the seasonal change [13][14][15].…”

Growth Hormone Induces Bone Morphogenetic Proteins and Bone-Related Proteins in the Developing Rat Periodontium

“…All of the cells involved in periodontal development are potential target cells for GH because they all express the GH receptor/binding protein, (14) although molar cementoblasts have been shown to be particularly responsive to GH in the hypophysectomized rat (15) . The bone morphogenetic proteins (BMPs) are important agents in formation of bone and tooth (16–19) and expression of both BMP‐2 and ‐4 recently has been shown to be induced by GH in dental pulp cells in culture, (20) both at the messenger RNA (mRNA) and protein expression level.…”

Growth Hormone and Insulin-Like Growth Factor I Induce Bone Morphogenetic Proteins 2 and 4: A Mediator Role in Bone and Tooth Formation?1

“…bone (1)(2)(3), dentine (4 -6), enamel (6,7), and cementum (8)]. bone (1)(2)(3), dentine (4 -6), enamel (6,7), and cementum (8)].…”