Scanning electron microscopy of rat neurointermediate lobe cells in culture.

Enzymatically dispersed cells of the rat pars nervosa -- pars intermedia (NI) were observed by scanning electron microscopy after 1, 2 and 4 days in culture. The cells attached to the plate slowly, requiring about 3--4 days for the majority to adhere. The epithelial cells became attached singly and in clumps and branched chains, often over a bed of fibroblast-like cells. After the first day in culture, few surface features were evident on the NI cells, but by day 2, the surfaces showed a small number of blebs. In 4-day cultures, the cells revealed extensive areas with blebs and microvilli, and a few structures resembling cilia were observed. The adrenocorticotrophic hormone content of the cells after 4 days in culture was similar to that found in fresh tissue.