Ultrastructure of the clear cell lining the epididymal lumen of the rat

2 types of clear cells can be distinguished in the rat epididymis. The Type I clear cell occurs in the middle segment and it is distinguished by a centrally located nucleus and the presence of lipid droplets. The Type II clear cell occurs in the terminal segment; it has a basally situated nucleus and does not have lipid droplets. Ultrastructural studies indicate that the clear cells carry out a dual function of absorbing substances from the epididymal lumen by pinocytosis and secreting products into it by merocriny. both these functions are not carried out simultaneously by a particular clear cell but at different times. The Type I clear cell appears to secrete a glycolipoprotein while the Type II clear cell seems to secrete glycoproteins.