Flutamide does not mediate testosterone effects on BMP4 response in wild‐type rabbit bone cells

Abstract

We previously reported that a treatment of testosterone (T) and BMP4 led to decreased proliferation and differentiation in rabbit calvarial bone cells. A primary sex difference was noted; males exhibited greater differentiation for suture bone and females for non‐suture bone. Those results suggested that T decreased response for BMP4 treated cells. We hypothesized that this effect is mediated through the androgen receptor (AR). Cells were treated with the AR blocker, flutamide (F), along with T and BMP4 to determine cellular response. Calvarial cells (suture or non‐suture) from New Zealand White rabbits (N=14) were stimulated with 50ng/ml BMP4 and T (10–16 dose), with or without F treatments (10‐8, ‐10 or ‐12 dose). Proliferation and differentiation were assessed after 7 days. Differences between F treatments by dose, sex, and bone‐type were analyzed. F did not effect BMP4 alone, p>.05. The dose response was biphasic, p<.05. Non‐suture bone was more susceptible to this F‐dependent decrease in proliferation p<.05, and male derived cells exhibited a greater decrease, p<.05. F did not effect differentiation p>.05, by dose, cell type, or sex, p>.05. These results suggest the effect T has on reducing BMP4‐induced differentiation may not be mediated through the AR pathway. An alternative pathway (e.g., MAPK) should be explored for the direct effect of T on normal calvarial bone cell response.Grant Funding Source: Internal