GROWTH-HORMONE REGULATES AN N-ACETYLGALACTOSAMINE COMPONENT IN ODONTOGENESIS - A SPECIFIC LECTIN-BINDING STUDY IN THE LEWIS DWARF RAT

Dental organs of incisors from normal, dwarf and growth hormone-treated dwarf rats were analysed histochemically using a panel of lectins. A distinctive pattern of differential staining was obtained with Helix pomatia agglutinin, a lectin specific for N-acetylgalactosamine. In Bouin's perfused and paraffin-embedded undecalcified tissues from normal rats, reaction product for N-acetylgalactosamine was Visible in the odontogenic cells and some extracellular matrices. In the growth hormone-deficient dwarf rats, the N-acetylgalactosamine reaction was consistently minimal in the odontoblasts, predentin, cementoblasts, cementoid, osteoblasts and osteoid matrices, although the staining of ameloblasts and osteoclasts was similar to normal. Administration of growth hormone to dwarf rats for six days (66 mu g/100 g rat b.i.d.) restored the reaction for N-acetylgalactosamine in the affected matrices. Thus, an N-acetylgalactosamine rich matrix component is differentially expressed during odontogenesis. Growth hormone may regulate this component in these matrices, which may be a proteoglycan or a glycoprotein, essential for normal growth of the teeth.