Evidence continues to accumulate for the presence and function of receptors for steroid hormones on the cell surface. The latest study, from Benten et al., demonstrates that testosterone causes increases in the intracellular concentration of calcium in a mouse macrophage cell line that appears to lack intracellular androgen receptors that produce the conventional transcriptional effects of the hormone. The effects of testosterone in these cells seems to be mediated by a receptor at the cell surface because testosterone coupled to bovine serum albumin also enhanced calcium mobilization. Inhibition of the action of testosterone by pertussis toxin and an inhibitor of phospholipase C indicates that a G protein-coupled receptor might be the membrane-localized target of testosterone in these cells. Whether testosterone's effects are physiologically relevant in macrophages remains unclear.
Benton, W.P. M., Lieberherr, M., Stamm, O., Wrehike, C., Guo, Z., and Wunderlich, F. (1999) Testosterone signaling through internalizable surface receptors in androgen receptor-free macrophages. Mol. Biol. Cell 10: 3113-3123. [Abstract] [Full Text]