title: Prostatic epidermal growth factor receptors and their regulation by androgens.
abstract: Prostatic membranes contain high affinity [dissociation constant (KD) = 1.16 nM], saturable binding sites for [125I]iodo-epidermal growth factor (EGF). The binding of [125I]iodo-EGF is specific since it is displaced by excess EGF but not by insulin, fibroblast growth factor, platelet-derived growth factor, or multiplication-stimulating activity. Affinity labeling with [125I]iodo-EGF and subsequent cross-linking with disuccinimidyl suberate demonstrated the specific binding of [125I]iodo-EGF to a macromolecule with a mol wt of 170,000. Castration of mature rats resulted in a 3- to 6-fold increase in [125I]iodo-EGF binding, while treatment of 7-day castrated rats with 5 alpha-dihydrotestosterone decreased the number of binding sites. Administration of estrogen or progesterone produced a slight decrease in EGF binding sites but not nearly to the extent observed with 5 alpha-dihydrotestosterone, suggesting that the observed effect is androgen specific. These results demonstrate that rat prostate contains specific binding sites for EGF and that their level is modulated by androgens.
mesh_terms: D000728:Androgens / Q000502:physiology*; D000818:Animals; D002369:Castration; D055598:Chemical Phenomena; D002621:Chemistry; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008566:Membranes / Q000378:metabolism; D011467:Prostate / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000728:Androgens; D004815:Epidermal Growth Factor; D066246:ErbB Receptors