Steroid binding sites in liver membranes: interplay between glucocorticoids, sex steroids, and pituitary hormones.

摘要: Abstract Steroid hormones activate target cells through specific receptors that discriminate among ligands based upon recognition of distinct structural features. For most known steroids, membrane and nuclear co-exist in many cells. However, while the structure their function as transcriptional activators genes is generally well understood, identity remains elusive. Using pharmacological biochemical approaches, we are beginning to characterize for glucocorticoids anabolic-androgenic steroids male rat liver membranes. Male endoplasmic reticulum contains two steroid binding sites which functionally related associated with a 90–134 kDa oligomeric protein: (1) low-affinity glucocorticoid site (LAGS), composed at least part peptides (37 53 kDa) bind (2) stanozolol protein (STBP), three (22, 31, 55 kDa) synthetic androgen stanozolol. These proteins have properties different from those classical receptors, salient differences being failure recognize “classical” together marked physiological regulation. The mechanism interaction LAGS can be clearly distinguished STBP. Moreover, STBP shows an extremely narrow profile, selective ST its analog, danazol, more than 100 non-steroidal compounds were assayed, including able displace LAGS. level activity undergoes dramatic variations following changes serum levels thyroid hormones, glucocorticoids, GH, vitamin A, E2. neither nor GH critical role on activity. We suggested novel whereby membrane-associated targeted by (and 16β-hydroxylated stanozolol): modulates negative allosteric modulation resulting effective increase GR-signaling increasing availability cytosolic GR.