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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An assay for plasma glucocorticoid activity has been developed using specific glucocorticoid receptors. Unlike other assays for cortisol and certain synthetic corticosteroids, this radioreceptor assay measures the glucocorticoid activity of all natural an synthetic steroids. Steroids extracted from as little as 0.05 ml of plasma are incubated with 3H-dexamethasone and cytosol receptors from cultured rat hepatome cells. From 0.5 to 50 ng of cortisol are accurately detected. Glucocorticoid activities of adult determined by the assay correlate closely with corticoid levels obtained in the CBG-isotope and fluorometric assays. Other steroids are measured in proportion to both concentration and potency as glucocorticoids. Relative activities include: cortisol 100, dexamethasone 940, prednisolone 230, prednisone 3, estradiol 1 and androstenedione 1. A similar ranking of steroids was found using receptors from a human source (fetal lung). The assay has been useful in detecting glucocorticoid activity in unidentified medications and in measuring plasma glucocorticoid levels after administration of synthetic corticosteroids. A modification of the assay is described for also estimating the level of free (unbound) glucocorticoid activity in plasma. Assays are performed before and after removal by charcoal of steroids not bound to plasma transcortin. This consideration is shown to be particularly important with prednisolone where the unbound steroid level is much less than the total. Thus, the radioreceptor assay provides a relatively simple technique for measuring the total of free plasma of glucocorticoid activity in man due to any natural or synthetic steroid or combination of steroids.
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PMID:A radioreceptor assay for evaluation of the plasma glucocorticoid activity of natural and synthetic steroids in man. 16 79

In adult male ducks submitted to marked variations in plasma testosterone concentration, plasma transcortin (CBG) levels were shown to be closely related to the level of plasma testosterone. In connection with previous data on female ducks, the results strongly support the evidence that at least in this species, CBG is under a stimulatory control by testosterone.
Steroids 1984 Apr
PMID:Androgen control of transcortin binding capacity in adult male ducks. 652 49

Corticosteroid-binding globulin (CBG or transcortin) is a specific plasma glycoprotein, which binds steroid hormones (cortisol, corticosterone, and progesterone), and plays a role in transporting these steroids, altering their concentrations in blood, and influencing their biological actions. CBG has been previously shown to be synthesized in the liver, but recently it has been reported that immunoreactive CBG is localized in target tissues. In the present work, CBG mRNA was detected in normal human endometrial tissues by Northern blot analysis and reverse transcription-polymerase chain reaction. Its level was higher (P < 0.05) in the secretory phase than in the proliferative phase. In the secretory phase, the endometrial CBG mRNA level was negatively correlated with the serum progesterone level (P < 0.01). While there was no positive correlation between the levels of endometrial CBG mRNA and serum estradiol (E2), there was a positive correlation between the endometrial CBG mRNA level and the serum E2/progesterone ratio (P < 0.05). These findings suggest that CBG is synthesized in the uterine endometrium, predominantly in the secretory phase, and that the serum E2/progesterone ratio exerts an influence on the synthesis of intracellular CBG.
Steroids 1994 Oct
PMID:Corticosteroid-binding globulin mRNA levels in human uterine endometrium. 787 88