The effect of intermediate filament inhibitors on steroidogenesis and cytoskeleton in Y-1 mouse adrenal tumor cells.

When Y-1 mouse adrenal tumor cells were treated with sodium orthovanadate, an agent disrupting BHK21-F cell microtubule-intermediate filament (IF) interactions, there was no change in the amount of 20-dihydroprogesterone produced. A neurofilament-microtubule perturbing agent, beta,beta-iminodipropionitrile (IDPN), enhanced the ability of Y-l cells to produce steroid in response to ACTH by acting on the plasma membrane. Electron microscopy of Y-l cells extracted with Triton X-100 revealed that both vanadate and IDPN caused the aggregation of granular structures in the perinuclear area. Based on the steroidogenic effects of IDPN, perinuclear granule aggregation may result from an altered interaction between intermediate filaments, microtubules and the plasma membrane. The reason for the ultrastructural changes caused by vanadate is unknown.