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-treate d 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 Bo uin's perfused and paraffin-embedded undecalcified tissues from normal rats, reaction product for N-acetylgalactosamine was Visible in the o dontogenic cells and some extracellular matrices. In the growth hormon e-deficient dwarf rats, the N-acetylgalactosamine reaction was consist ently minimal in the odontoblasts, predentin, cementoblasts, cementoid , osteoblasts and osteoid matrices, although the staining of ameloblas ts and osteoclasts was similar to normal. Administration of growth hor mone to dwarf rats for six days (66 mu g/100 g rat b.i.d.) restored th e reaction for N-acetylgalactosamine in the affected matrices. Thus, a n N-acetylgalactosamine rich matrix component is differentially expres sed during odontogenesis. Growth hormone may regulate this component i n these matrices, which may be a proteoglycan or a glycoprotein, essen tial for normal growth of the teeth.