Abstract: Histochemical changes of the superficial epithelium and the glandular epithelium during estrus cycle and early pregnancy in rats were investigated. The results indicated that during diestrus the activity of ACP, G6Pase, NSE was declined and the amounts of glycogen and lipid were quite low as well. During estrus the activity of NSE, ACP and SDH was increased, which suggested that the metabolism of carbohydrate and lipid became very active. At the 6th day of rat pregnancy the amounts of glycogen and lipid and the activity of ACP, G6Pase, NSE were clearly raised, which suggested that the nutrition of blastocyst during implantation probably provided by the superficial epithelium. In addition, the superficial epithelium showed positive reaction to 3-β-HSDH, but its significance remains to be studied.

Key words: endometrium, histochemistry, rat