Control of 2,3,7,8-tetrachlorodibenzo-p-dioxin binding protein(s) in the hamster kidney

Hamster renal cytosol binds [3H]-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with high specificity. Sucrose density gradient centrifugation revealed two binding entities- one with a low sedimentation coefficient of 4-5 S which was displaced by neither TCDD nor other polycyclic aromatic hydrocarbons (PAHs) and another with a high sedimentation coefficient of 7-8 S which was displaced by TCDD, benzo[a]pyrene (BP), 2-methylcholanthrene (MC), and 7,12-dimethylbenzo[a]anthracene (DMBA) but not by estradiol (E), progesterone (P), cortisol (F), testosterone (T), 5 alpha-dihydrotestosterone (DHT), or methyltrienolone (R-1881), a synthetic androgen. Cytosol from intact male hamsters showed maximum binding of labelled TCDD to the 7-8 S binding site. Castration or hypophysectomy reduced this binding. Pretreatment with DMBA increased binding, whereas diethylstilbestrol (DES) decreased binding. Sex difference was observed in the binding capacity of renal cytosol. This is the first report of endocrine control over TCDD binding and its modulation by other PAHs and steroids.