Glucocorticoid-Binding Macromolecules in the Lactating Mammary Gland of the Vole

Abstract

Macromolecules binding 3H-triamcinolone acetonide specifically were detected in the cytosol fraction of the lactating mammary gland of the vole (Microtus montanus). These receptors exhibited sedimentation coefficients of 7-8 Svedbergs and dissociated into lower molecular weight components (4-5 Svedbergs) when separated on sucrose gradients containing 0.4M KCl. The dissociation constant (Kd) of the 3H-triamcinolone acetonide-receptor complexes, using a charcoaladsorption procedure, was 1.3 × 10−8M; the number of binding sites was 250 fmoles/mg cytosol protein. (Endocrinology95: 1770, 1974)