The origin of progesterone in blood when a bacterial solution is infused into the uterus of rats.

PURPOSE

The infusion of a bacterial solution into the uterus of rats raises the progesterone (P) concentration in serum and extends diestrus. To understand the origin of the P, we investigated the change in the P concentration of seven groups of rats for 5 days after the infusion of a bacterial solution.

METHODS

The rats were divided into 7 treatment groups as follows: OvxBac, AdxBac, Ovx, Adx, LapBac, Lap, and Cont. In OvxBac, rats received both ovariectomy and bacterial inoculation into their uterus. In AdxBac, rats received both adrenalectomy and bacterial inoculation into their uterus. In Ovx, rats received only ovariectomy. In Adx, rats received only adrenalectomy. In LapBac, rats received only bacterial inoculation into their uterus. In Lap, rats received only laparotomy. In Cont, rats did not receive any treatment and acted as controls.

RESULTS

The P concentration in all treatment groups was higher than in Cont on day 1 (the day following operation) and day 2. In Lap and LapBac, the P concentration was high on day 1 (>30 ng/mL) and maintained that value until day 2. In Adx and AdxBac, the P concentration was average on day 1 (approximately 25 ng/mL) and increased on day 2 to a value close to that of LapBac and Lap. In OvxBac, although the P concentration increased slightly on day 1 and day 2, it reached 22.5 ± 7.5 ng/mL on day 4. In AdxBac and LapBac, the P concentration on day 4 tended to be high.

CONCLUSION

These results suggest that P is initially secreted from the ovaries and the adrenals in response to the surgical stress of laparotomy, and is later secreted from the adrenals due to the inflammatory reaction of the uterus.