EXPRESSION OF NEUROTROPHIN-3 IN THE GROWING VELVET ANTLER OF THE RED DEER CERVUS-ELAPHUS

Antlers are organs of bone which regenerate each year from the heads o f male deer. In addition to bone, support tissues such as nerves also regenerate. Nerves must grow at up to 1 cm/day. The control of this ra pid growth of nerves is unknown. We examined the relative expression o f neurotrophin-3 (NT-3) mRNA in the different tissues of the growing a ntler tip and along the epidermal/dermal laver of the antler shaft of the red deer Cervus elaphus, using semi-quantitative reverse transcrip tion-polymerase chain reaction. Expression in the tip was found to be highest in the epidermal/dermal layer and lowest in the cartilaginous layer in all developmental stages examined. These data correlate well with the density and pattern of innervation of these tissues. Along th e epidermal/dermal layer of the antler shaft, expression was highest i n the segments subjacent to the tip and lowest near the base, arguing for differences in the temporal expression of NT-3 in these segments. The expression of NT-3 in cells isolated from the different layers of 60-day antlers did not mirror that observed when whole tissues were us ed and may suggest regional specificity of NT-3 expression within antl er tissues.