Studies on the uterine fluid of rat

Changes of protein contents and disc electrophoretic patterns during estrous cycle

Abstract

There is no information on the qualitative and quantitative alteration of uterine fluid in the rat. This experiment was designed to investigate the biochemical alteration of protein in uterine fluid during estrous cycles in the rat.
Adult virgin Wistar rats, weighing from 180 g to 280 g, was used. Uterine fluid (UF) was obtained from the uterus by flushing with 0.8 ml of saline solution. When the uterus was clearly distended with fluid, the accumulated uterine fluid (AUF) was aspirated with tuberculin syringe. Concentration of protein in uterine fluid was determined by the method of DAUGHADAY, using bovine serum albumin as standard protein. Patterns of protein in uterine fluid were analyzed by polyacrylamide gel disc electrophoresis with a 7.5% running gel. The gels were stained with amido black for protein detec-tion and with periodic acid-Schiff reagent (PAS) for carbohydrate detection after the electrophoresis. The protein fractions were measured as areas under absorption peaks from densitometric tracings.
The results obtained were as follows:
1. AUF appeared between 6:00 hr of proestrus and 6:00 hr of estrus. The fluid increased pro-gressively and reached maximum at 22:00 hr of proestrus (see Table 1).
2. The total content of protein in UF was significantly higher in proestrus than that in other stages of estrous cycle (see Fig. 1), and increased to maximum at 22:00 hr of proestrus. Then they diminished at 6:00 hr of estrus.
3. Protein concentration of AUF collected from 6:00 hr of proestrus to 6:00 hr of estrus was lower in this experiment than the results of others (Table 1).
4. Protein bands in densitometric tracing of the serum and UF were detected 15 and 12, respec-tively. Those protein bands were divided to 8 fractions (A to H) according to the Rf values. The pattern of protein in proestrous UF was different from those of other stages resembling to the pattern of serum protein (Table 2). The alteration of their fractions appeared from 6:00 hr of proestrus to 6:00 hr of estrus. It has been obtained that B fraction (albumin) was one quarter and H fraction (γ-glo-bulin) was at least twofold in comparison with those of serum (Table 4).
5. Glycoprotein fractions of serum and UF were shown in Table 3 and 5. Since patterns of glycoprotein were similar to patterns of protein in UF obtained from 10:00 hr of proestrus to 6:00 hr of estrus, it was suggested that much glycoprotein have been contained in these UF than in UF of other stages.