Binding of sex steroid binding protein to plasma membranes of human testis.
The existence of a specific binding site for sex steroid binding protein (SBP or SHBG) was detected on plasma membranes prepared from the testis of a patient affected by a variant form of testicular feminization. A binding technique using [125I]SBP as a tracer allowed us to identify a single set of binding sites, characterized by a Kd of 1.917 x 10(-11) M. The maximum number of binding sites was 5.2 fmol/mg membrane protein. Membranes were also prepared from a sample of genital skin from the same patient, but no binding for [125I]SBP was detectable. The evidence of the SBP membrane receptor in the testis of a patient affected by Morris syndrome extends our knowledge about the tissue distribution of the SBP receptor and suggests the possible implication of SBP and its recognition system in a disorder related to peripheral androgen insensitivity.
Frairia
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Dipartimento di Fisiopatologia Clinica, Università degli Studi di Torino, Italy.
Fortunati
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N
Revelli
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Guidetti
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Cavaglià
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Massobrio
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D013734:Androgen-Insensitivity Syndrome / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005837:Genitalia, Male / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011485:Protein Binding; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D012867:Skin / Q000378:metabolism; D013737:Testis / Q000378:metabolism*
D011956:Receptors, Cell Surface; D012738:Sex Hormone-Binding Globulin; C063572:sex hormone-binding globulin receptor