Zhang Rongqing

Immunohistochemical and in situ hybridization studies of gonadotropin releasing hormone (GnRH) and its receptor in rat digestive tract

GnRH(LH-RH) is first discovered in the hypothalamus and found to have a role in regulation of reproduction. With the study on it deepening, GnRH was demonnstrated that it also exists in a number of organs beyond the hypothalamus and acts on extrapituitary organs. To study whether digestive tract synthesizes GnRH and its receptor and, if it does, by what cells. In the experiment, the locallizations of GnRH and its receptors in rat digestive tract were studied using immunohistochemistry and in situ hybridization. The parietal cells of gastric gland, the villous and glandular epithelium in small and large intestine and parasympathetic ganglion cells of myenteric plexus showed GnRH immunoreactivity; GnRH mRNA hybridization signal was detected. The epithelium of gastric pit and the cells above in digestive tract showed GnRH receptor immunoreactivity; GnRH receptor mRNA hybridization signal was detected. The immunoreactive and signal materials distributed in cytoplasm of all positive cells, with nuclei being immunonegative and with no hybridization signal. These results suggested that the digestive tract can produce GnRH and express GnRH receptor; GnRH may also be a gastrointestinal hormone.

A sensitive enzyme-linked immunosorbent assay for evaluating the concentration of bee venom in rat plasma.

A simple and reproducible enzyme‐linked immunosorbent assay (ELISA) was developed to determine the concentration of bee venom in rat plasma. The intra‐ and inter‐assay coefficients of variation for the ELISA were less then 3% between 0.1 and 1000 ng mL−1 venom, and the sensitivity of the detection was 0.1 ng mL−1. Total recovery of the bee venom added to rat plasma was determined. Using this ELISA, serum levels of bee venom were easily determined. The rats were administered a single intravenous injection or oral dose of bee venom (1 mg kg−1 of body weight). The bioavailability of the bee venom under the two administrations was compared using pharmacokinetic parameters. Results showed that intravenous administration of bee venom produced high plasma concentrations with a short half‐life. The area under the curve for oral administration was 10 times lower than for intravenous administration. This loss of bee venom may be due to the degradation that occurs in the enzymatic and acidic environment of the gastrointestinal tract.

Localization and quantitative analysis of interleukin-6 in human placenta

The localization of IL-6 at light microscopic levels and its quantitative analysis in human placentas were studied by using immunohistochemistry. Both syncytiotrophoblast and cytotrophoblast in placental villi, white blood cells in villose capillary cavity stromal cells and capillary endothelium present IL-6 immunoreactivity in cytoplasm. Using a quantitative immunohitochemical method, the amounts of IL-6 in placenta were low at the 6th week of gestation, increased saliently and peaked at the 7th, then reduced gradually during the rest of the gestation period and maintained the same level as that in the 6th week of gestation. This changing trend was paralleled with that of GnRH in our previous studies. These results revealed that IL-6 could be produced by the human placenta and may take part in the regulation of placental hormone releasing.

合浦珠母贝转录因子 PF - CREB3L2 基因的克隆和鉴定

克隆得到了合浦珠母贝（Pinctada fucata）PF-CREB3L2蛋白的cDNA序列，其cDNA全长1 983 bp，其中开放阅读框长度为1 728 bp，编码的蛋白含有575个氨基酸残基。组织表达分布实验发现，其在合浦珠母贝内脏囊中表达量最高，在外套膜和鳃中也有大量表达，推测其广泛参与合浦珠母贝的贝壳形成等生理活动。贝壳损伤修复实验中发现，在合浦珠母贝贝壳受到损伤后，PF-CREB3L2和基质蛋白的表达量会迅速上升，且PF-CREB3L2的峰值出现更早，推测其通过影响基质蛋白转录，参与合浦珠母贝生物矿化的调控过程。PF-CREB3L2与合浦珠母贝基质蛋白表达相关性的分析发现，PF-CREB3L2与Prisilkin39、KRMP的表达量呈现显著的正相关，说明其可能特异性地调控某些基质蛋白的转录。