| Abstract: | Androgen binding has been studied in the prostate cytosol of zinc deficient rats by charcoal assays. Rats were housed individually in plastic cages and maintained on a zinc deficient diet for 3 months. The cytosol fraction of prostate gland was incubated with various concentrations of tritiated methyltrienolone (3H-R1881, a synthetic androgen) alone or in the presence of 500-fold excess of radioinert R1881. Scatchard analysis of the data revealed that the number of androgen binding sites in the cytosol fraction of the zinc deficient rat prostate was 31 +/- 5.2 fmol/mg cytosol protein. This was significantly lower than that (84 +/- 11.5 fmol/mg protein) of the controls. Their dissociation constant (Kd = 1.6 +/- 0.6 nM) on the other hand was not different from that (1.7 +/- 0.7 nM) of control animals. This decrease in the concentration of cytosol receptor sites in the zinc deficient state suggests that this metal is involved in the androgen-binding process in the target cells. |
