Uterine protein profiles in ovariectomized dairy cows administered progesterone and estradiol-17β

Abstract

Twenty-seven multiparous normally cycling non-lactating dairy cows were ovariectomized on day 4 following estrus and implanted with progesterone (P 4), estradiol-17β (E 2), both hormones or no hormone to determine the effects of ovarian steroids on qualitative and quantitative changes in uterine proteins. Implants contained either 4 or 8 g P 4, 2 or 2.5 mg E 2, 4 g P 4 and 2 mg E 2, 8 g P 4 and 2 mg E 2, 4 g P 4 and 2.5 mg E 2, 8 g P 4 and 2.5 mg E 2 or neither hormone. Blood samples were obtained by jugular venipuncture on the day of implant insertion, on days 1 and 2 and every second day for 54 days for analysis of P 4. Uterine fluids were obtained by nonsurgical, transcervical procedures at 18, 36 and 54 days after implantation. During the third 18-day period, cattle were additionally treated with daily subcutaneous injections of 0, 0.25 and 0.5 mg P 4/kg and 0, 0.125 and 0.156μ E 2/kg in ratios identical to implant received. Total recoverable protein ranged from 11.4 to 101.0 mg and was not different between treatments. Red blood cell contamination of raw uterine fluid ranged from 0.2 to 50 million cells per milliliter. Mean plasma P 4 over the first 36 days was 0.32 ± 0.02 ( X ± SE ) for no P 4, 1.55 ± 0.06 for 4 g P 4 and 2.27 ± 0.09 ng/ml for 8 g P 4 implants. Injections increased P 4 to approximately 4.5 and 6.5 ng/ml plasma for 0.25 and 0.5 mg P 4/kg dosages. A protein with an electrophoretic mobility (Ra) of 0.638 may be a hemoglobin contaminant of uterine fluid. A band with a mobility of 0.802 was observed more frequently in plasma than uterine fluid. Three bands (0.117, 0.724 and 1.240) were found more frequently in uterine flushings than plasma and may be of uterine origin. Acidic protein bands at 1.410, 1.570 and 1.660 were found only in uterine flushings of P 4 treatments and may be induced by P 4. A basic protein migrating 1.34 cm toward the cathode was found in gels from cattle receiving treatments including P 4. The data support the concept that hormonal induction of uterine specific proteins may occur in the bovine.