Pedicle and first antler formation in deer: Anatomical, histological, and developmental aspects

Abstract

Formation of primary cranial appendages (pedicles and first antlers) in deer is initiated by a specialized periosteum, for whichGoss (1983) introduced the term antlerogenic periosteum. The antlerogenic periosteum (AP) is located on the external frontal crests, this area of the deer skull most likely being of neural crest origin. As was discovered byHartwig (1968b) andHartwig andSchrudde (1974), AP is capable of autonomous differentiation even when grafted to other regions of the body, thereby causing the growth of ectopic pedicles and antlers. This means that the cells of the AP are determined for pedicle and antler formation. There is further evidence that the cells forming the bony component of regenerating antlers are derivatives of the AP and that the AP contains crucial morphogenetic information for antler shape. The cells of the AP and its derivative, the antler perichondrium, exhibit features (high glycogen content, long life spanin vitro) that are normally only found in embryonic cells. These findings support our hypothesis, originally based on studies of double-head antlers, that the growth of both primary cranial appendages (pedicles and first antlers) and of regenerated antlers depends on a population of antlerogenic periosteal stem cells.