Estrogen-Receptor Expression and Function in Thymocytes in Relation to Gender and Age

The expression of estrogen receptor (ER) in thymocytes was studied in young, middle-aged, and old (2, 12, and 24 months, respectively) female and male C57BL/6J mice. Western immunoblots prepared from the thymocytes of females of all age groups showed the presence of a 67-kD protein band, which has been associated with the apparent MW of denatured ER. Flow cytometry analysis o,f cells stained with a monoclonal anti-ER antibody (clone 13H2) disclosed ER expression in both females and males of all age groups. In vivo treatment with estradiol (E2) led to an increase in the specific activity of thymic creatine kinase (CK) in the female mice, whereas the male thymocytes responded with an increase in CK activity only on treatment with dihydrotestosterone (DHT). The data show no differences in ER expression between male and females, but the receptor appears not to be functional in males. Interestingly, when estradiol was applied to co-cultures of lymphoid-depleted fetal thymus (FT) explants and bone-marrow cells, or thymocytes, from young and old females, it resulted in increased cellularity of cultures containing cells of the young, and not those of the old. The proportion of CD4/CD8 phenotypes of the developing cells in these cultures was not affected by E2 treatment. These observations provide a new insight into ER expression and function in T-cell development in relation to gender and age

Dietary N-3 polyunsaturated fatty acids decrease biliary cholesterol saturation in gallstone disease

Because fatty acid composition of biliary phospholipids influences cholesterol secretion into bile, we investigated whether replacement of n-1 monounsaturated or n-6 polyunsaturated fatty acids with n-3 polyunsaturated fatty acids in biliary phosphatidylcholines reduces supersaturation with cholesterol and prevents precipitation of cholesterol crystals in bile of gallstone patients. Seven patients with radiolucent gallstones in functioning gallbladders were studied before (control) and after 5 wk of dietary supplementation with marine fish oil (11.3 gm/day = 3.75 gm n-3 polyunsaturated fatty acids/day). Duodenal bile was collected for analysis during intravenous infusion of cholecystokinin. Gallbladder emptying in response to cholecystokinin was comparable before and during intake of n-3 polyunsaturated fatty acids. Intake of n-3 polyunsaturated fatty acids increased (p < 0.001) the fractions of eicosapentaenoic and docosahexaenoic acids and decreased the fractions of linoleic (p < 0.001) and arachidonic acids (p < 0.02) in biliary phospholipids. Concomitantly, the molar ratio of cholesterol to phospholipids decreased (-19%; p < 0.05). As a consequence, the cholesterol saturation index was reduced by -25% (p = 0.01), from 1.60 ± 0.44 to 1.24 ± 0.38. However, in vitro nucleation time of duodenal bile was not prolonged. The decrease in cholesterol saturation was not sufficient to prevent nucleation of cholesterol crystals in bile of gallstone patients. In conclusion, our data suggest that cholesterol saturation can be influenced by the fatty acid composition of the phosphatidylcholines secreted in bile

Expression of genes for estrogen receptors α and β in human articular chondrocytes

AbstractObjective To investigate the gene expression of estrogen receptor (ER) α and ERβ in human articular chondrocytes.Methods 16 articular cartilage specimens were obtained from 15 patients during surgery. Three of the specimens were from men and 13 from women; three from hip joints and 13 from knee joints; four were normal and 12 showed osteoarthritic cartilage. Total RNA was extracted from the articular chondrocytes and the expression of both ERα and ERβ genes was investigated by the reverse transcription-polymerase chain reaction (RT-PCR) method.Results Gene expressions of ERα were detected in all specimens and those of ERβ were found in 15 specimens by the RT-PCR method. There was a significant correlation between the amounts of ERα and ERβ. Expression levels of both genes were significantly higher in men than in women. There were no significant differences in the expression levels of both ER genes between the hip and knee joint sites, nor between normal and osteoarthritic tissues.Conclusion This study is to our knowledge the first to demonstrate the gene expression of both ERα and ERβ in human articular chondrocytes. Since there are some functional differences between the two receptors, the effects of estrogen on cartilage metabolism should be elucidated by two different receptor mechanisms.{copy