BackgroundRhus verniciflua Stokes is an Asian tree species that is used as a food supplement and traditional medicine in Korea. However, its use is restricted by its potential to cause allergy. Thus, allergen-free R. verniciflua extracts are currently being marketed as a functional health food in Korea. In the present study, three different allergen-free R. verniciflua extracts (DRVE, FRVE, and FFRVE) were produced by detoxification of R. verniciflua, and their properties and constituents were compared.MethodsThe main components and properties (antibacterial, antioxidant, anticancer, and hepatic lipogenesis inhibitory effects) of the three allergen-free extracts were compared. Moreover, the major phenolic constituents of R. verniciflua, including gallic acid, fustin, fisetin, and quercetin, were analyzed in the three extracts.ResultsDRVE was superior to the two other extracts with regard to antioxidant activity, while FRVE was superior with regard to antimicrobial activity and suppression of hepatic lipogenesis. FRVE exhibited lipid-lowering effects by lowering sterol regulatory element-binding protein 1 and triglyceride levels, and promoting the activation of peroxisome proliferator-activated receptor and AMP-activated protein kinase in an in vitro model of non-alcoholic fatty liver.ConclusionsOverall, our findings demonstrate various differences among the three extracts. This suggests that functional and bioactive compounds present in R. verniciflua could be altered by the detoxification process, and this property could be considered in the development of functional health foods in the future.

In sheep, the control of tonic and surge GnRH secretion is sexually differentiated by testosterone in utero. However, GnRH neurons are not sexually dimorphic with respect to number, distribution, or gross morphology. Therefore, this study tested the hypothesis that prenatal steroids influence synaptic input to GnRH neurons. We compared the number of synapses on GnRH neurons from male, female, and androgenized female lambs (n = 5 each). Androgenized females were exposed to testosterone during mid-gestation. Yearling lambs were perfused, and GnRH neurons were visualized using the LR-1 antibody. Five to seven GnRH neurons from the rostral preoptic area in each animal were viewed at the ultrastructural level. Afferent synapses and glial ensheathment on each neuron were counted in a single section through the plane of the nucleus. GnRH neurons from females received approximately twice as many contacts (3.6 +/- 0.7 synapses/100 microm plasma membrane) as those from male lambs (1.6 +/- 0.3; p < 0.05), similar to previous reports in rats. In addition, the number of synapses on GnRH neurons from androgenized female lambs (1.5 +/- 0.5) was similar to that from male lambs, suggesting that prenatal steroids give rise to sex differences in synaptic input to GnRH neurons.

To determine if prenatal androgens prevent activation of GnRH neurons in response to estradiol stimulation, Fos colocalization with GnRH was compared in the brains of normal female lambs, normal males, and androgenized females in response to a surge-inducing dose of estradiol. Blood samples were collected every 1-2 h for 6 h before estradiol treatment up to the time of sacrifice at 17-19 h post-treatment. Following perfusion, 60 micrograms coronal brain sections were immunostained for Fos (1:1000, Santa Cruz Biochemicals) and GnRH (1:40,000, LR-1) using NiCl-enhanced and unenhanced DAB, respectively. Although LH secretion increased in females before sacrifice, no increase was observed in males or androgenized females. Despite differences in LH secretion, the number and distribution of GnRH neurons was not sexually dimorphic. Moreover, Fos immunostaining was visible throughout steroid-responsive limbic regions in all three groups of lambs. However, the colocalization of Fos with GnRH was highly sexually dimorphic. In females perfused after the peak of the LH surge, 65.7% of GnRH neurons in the preoptic area, anterior hypothalamus, and mediobasal hypothalamus expressed Fos, whereas only 1.7% of GnRH neurons were Fos-positive in males and androgenized females. These findings indicate that sex differences in the activation of GnRH neurons in response to estradiol are determined prenatally through the actions of testosterone.

To determine if prenatal androgens prevent activation of GnRH neurons in response to estradiol stimulation, Fos colocalization with GnRH was compared in the brains of normal female lambs, normal males, and androgenized females in response to a surge-inducing dose of estradiol. Blood samples were collected every 1-2 h for 6 h before estradiol treatment up to the time of sacrifice at 17-19 h post-treatment. Following perfusion, 60 micrograms coronal brain sections were immunostained for Fos (1:1000, Santa Cruz Biochemicals) and GnRH (1:40,000, LR-1) using NiCl-enhanced and unenhanced DAB, respectively. Although LH secretion increased in females before sacrifice, no increase was observed in males or androgenized females. Despite differences in LH secretion, the number and distribution of GnRH neurons was not sexually dimorphic. Moreover, Fos immunostaining was visible throughout steroid-responsive limbic regions in all three groups of lambs. However, the colocalization of Fos with GnRH was highly sexually dimorphic. In females perfused after the peak of the LH surge, 65.7% of GnRH neurons in the preoptic area, anterior hypothalamus, and mediobasal hypothalamus expressed Fos, whereas only 1.7% of GnRH neurons were Fos-positive in males and androgenized females. These findings indicate that sex differences in the activation of GnRH neurons in response to estradiol are determined prenatally through the actions of testosterone.