The purpose of this study was to estimate morphological changes in the ovary and size of the production of
steroid hormones during the luteal phase of the estrous cycle in pigs after intraovarian infusions of
Escherichia coli endotoxin. Polish Large White gilts (n = 15) of similar age (7-8 months) and
body weight (90-110 kg) with two controlled subsequent estrous cycles were used. The animals were randomly divided into two groups: control (n = 9, the 10th day of the estrous cycle,) and treated with
Escherichia coli endotoxin (n = 6, the same day of the estrous cycle). The gilts were infused with
Escherichia coli endotoxin at a dose of 1 mg three times a day during six consecutive days, from the 14th to the 19th day of the estrous cycle. Plasma concentrations of
progesterone (P4),
androstenedione (A4),
testosterone (T),
estrone (E1) and
estradiol-17 beta (E2) were determined by radioimmunoassay method. Infusions of
Escherichia coli endotoxin resulted in a significant (p < 0.001) decrease in the production of P4, A4, T, E1 and E2 in the luteal phase as compared with the levels found in the control animals. Plasma level of P4, A4 and T was decreased by 84.6%, 86.0% and 73.0%, respectively. Plasma concentrations of E1 and E2 in some cases exceeded 5 pg/ml, nevertheless in the majority of the samples they were under sensitivity of the method.
Escherichia coli endotoxin infusions resulted in a considerable decrease in the size of the ovaries, and morphological changes characteristic for acute and chronic
inflammation were observed.