Decrease in activity of hypothalamic beta-endorphin (beta-EP) is an important factor for inducing the preovulatory LH surge. To study whether hypothalamic mu opioid receptor is involved in this process, changes in densities of hypothalamic mu opioid receptors were observed in this study by autoradiography and image process during cupric acetate (CuAC)-induced preovulatory LH surge in rabbits. New Zealand female rabbits were injected 1% CuAC 0.9 ml or saline 0.9 ml and sacrificed at different times after the injection. The densities of mu opioid receptor in the medial basal hypothalamus (MBH) and the medial preoptic area (MPO) were measured. A transient increase in densities of MPO mu opioid receptor were observed 1 h after CuAC injection (P < 0.05). The densities of MPO mu opioid receptor decreased significantly before the onset of the LH surge (P < 0.05) and remained at a low level during the surge. The change in densities of mu opioid receptor in the MBH was similar to those in the MPO. No change was observed in the saline control group. There was a negative correlation between the changes in densities of MBH mu opioid receptor and serum LH levels in the process of LH surge. The results suggest that the decrease of hypothalamic mu opioid receptor may be involved in the preovulatory LH surge.
Chemical studies on a number of plant resources (including TCM) have led to the identification of a big array of structurally interesting and/or bioactive components [1]. A few of the compounds have been selected as lead structures for our drug discovery program, and a number of modified chemical entities with significantly improved activities were also obtained. Biological evaluation showed that some of the compounds exhibited remarkable anticancer (both cytotoxic and antiangiogenesis) and antifungal activities. Several groups of anticancer and antimicrobial analogous showed very clear structure activity relationships. The research also provided good scientific background to understand the function and toxicity of some traditional Chinese medicine.
Lymph node (LN) metastases in papillary thyroid microcarcinomas (microPTCs) are common. The lymph node ratio (LNR) has been proposed as a risk factor for recurrence in papillary thyroid cancer. However, its relevance in microPTC is undetermined.