Subcellular localization of LH-dependent phosphoproteins and their possible role in regulation of steroidogenesis in rat tumour Leydig cells.

Stimulation of rat tumour Leydig cells with LH resulted in phosphorylation of 7 proteins of 17, 22, 24, 33, 43, 57 and 76 kDa, and in dephosphorylation of a single protein of 20 kDa. The subcellular localization of these LH-dependent phosphoproteins in combination with effects of inhibitors of microfilament formation and protein synthesis, suggest that phosphoproteins of 20, 43 and 76 kDa present in the cytosol may be involved in the action of microfilaments, whilst phosphoproteins of 24 and 33 kDa present in microsomes may be involved in specific protein synthesis.