BINDING of SEX-HORMONE-BINDING GLOBULIN (SHBG) TO TESTICULAR MEMBRANES and SOLUBILIZED RECEPTORS

Fecha
1992-11-01Autor
Porto, C. S.
Abreu, L. C.
Gunsalus, G. L.
Bardin, C. W.
Tipo
ArtigoISSN
0303-7207Es parte de
Molecular and Cellular EndocrinologyDOI
10.1016/0303-7207(92)90208-NMetadatos
Mostrar el registro completo del ítemResumen
Sex-hormone-binding globulin (SHBG) binds to a specific protein on the surface of prostate, epididymis, and a human breast cancer cell line (MCF-7), and is internalized by these cells. the present study demonstrated specific binding of SHBG to receptor on membranes prepared from rat testes. the binding was saturable, specific, and time and temperature dependent. Scatchard analysis of these binding studies suggested that SHBG binds to a single class of sites on testicular membranes with a K(d) at 37-degrees-C of 5 X 10(-8) M and a binding capacity of 30 +/- 0.6 pmol/mg protein. These binding characteristics are similar to the SHBG receptor on human prostate and MCF-7 cells. Solubilization of the receptor resulted in a 5-fold increase in its binding capacity (158 +/- 0.3 pmol/mg protein) and a 10-fold decrease in binding affinity (K(d) at 37-degrees-C = 6.5 X 10(-7) M). the apparent molecular weight of the testicular SHBG receptor, as estimated by gel filtration, was M(r) = 174,000. Conclusion: a specific binding site for SHBG was identified on testicular membranes. This binding site has been tentatively identified as a SHBG receptor based on its physical properties in testicular membrane preparations and following solubilization.
Cita
Molecular and Cellular Endocrinology. Clare: Elsevier Sci Ireland Ltd, v. 89, n. 1-2, p. 33-38, 1992.Palabras clave
CELL RECEPTORSEX-HORMONE-BINDING GLOBULIN
ANDROGEN-BINDING PROTEIN
MEMBRANE
(RAT TESTIS)
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