Histogenesis of fat tissue in the regenerating tail of the lizard (Lampropholis spp.)

Abstract

The differentiation of fat cells in the regenerating tail of the lizards Lampropholis delicata and L. guichenoti was studied until the 55th day post amputation. To study the proliferation of and protein synthesis in fat cells, tritiated thymidine and proline were injected into lizards after 3 weeks of tail regeneration and the tracers were revealed by optical and electron microscopic autoradiography. After 3 weeks of tail regeneration, adipocytes are rarely seen in the apical regions of the regenerating tail and most of the preadipose cells are visible in the submuscular connective tissue in the proximal regions. Fat cells begin to proliferate and accumulate visible lipid droplets in the proximal submuscular connective tissue after about 3 weeks of tail regeneration. The kinetics of [3H]thymidine uptake after progressive postinjection periods suggest that fat tissue mass increases mostly as as result of fat cell hypertrophy, with only limited cell multiplication. During the initial stages of their differentiation, lipoblasts also take up [3H]proline, but the ergastoplasm and Golgi apparatus become reduced during the process of fat accumulation. The final size of regenerated fat cells was less than that of the original fat cells.