No abstract

ET-1 and ET-3 increased the synthesis of type I and III collagens, whereas ET-1, but not ET-3, reduced collagenase activity. The effects of endothelins on collagen synthesis in cardiac fibroblasts seem to be mediated through ETA and ETB receptors, whereas their effects on collagenase seem to be mediated by ETA receptors.

Samples of connective tissue obtained from the hoof of six laminitic and eight non-laminitic adult horses were analysed zymographically to investigate whether connective tissue matrix metalloproteinases are activated or induced during laminitis. The activity or matrix metalloproteinases was substantially greater in the tissues from the laminitic horses than in the tissues from the non-laminitic horses. A comparison of the collagenolytic activity in the laminitic and control tissues showed that collagenolytic activities corresponding to the 92 kDa (P < 0.001), 72 kDa (P < 0.01) and 66 kDa (P < 0.01) bands were induced in the laminitic tissues.