The regulation of growth plate cartilage turnover.

The advances made in the areas of genetics and nutrition during this century have resulted in improved growth rates for livestock. However, one drawback has been the increased prevalence of long bone growth problems, such as rickets, avian tibial dyschondroplasia, and osteochondrosis. Growth plate cartilage, which regulates long bone development, must maintain a tightly controlled balance between cartilage synthesis and degradation as well as chondrocyte proliferation and apoptosis. This paper will briefly review the various nutritional factors, cell signals, and proteins that help regulate growth plate chondrocytes. Some of the growth plate diseases will be discussed with an emphasis on how a breakdown in growth plate metabolism is related to the observed problems. The author's intention is that readers will gain an appreciation for the complexity of this relatively small tissue and for why a better understanding of its physiology will be important in the years to come for the prevention of skeletal problems related to long bone growth.