Stimulation of progesterone production in bovine luteal cells by co-incubation with bovine blastocyst-stage embryos or trophoblastic vesicles.

A study was conducted to determine whether bovine blastocyst-stage embryos and trophoblastic vesicles stimulate the production of progesterone in bovine luteal cells during incubation in vitro. The effects of co-incubation of these embryos and vesicles with uterine endometrial tissue on progesterone production was also investigated. Bovine small and large luteal cells were obtained on day 12 of the oestrous cycle, dispersed by unit gravity sedimentation and recombined to provide preparations free of accessory cells. Blastocyst-stage embryos were obtained on day 7 and trophoblastic vesicles were obtained from bovine embryos on day 12. A uterine endometrial tissue sample was obtained from the same cow from which the corpus luteum was taken. Treatment groups were arranged in 24-well plates as follows: luteal cells alone; luteal cells and one trophoblastic vesicle; luteal cells and one blastocyst embryo; luteal cells and a 10 mg uterine endometrial sample; luteal cells, one trophoblastic vesicle and a uterine endometrial sample; and luteal cells, one blastocyst embryo and a uterine endometrial sample. All treatment groups were incubated (at 37 degrees C under 5% CO2) in Ham's F-12 medium supplemented with antibiotics (100 micrograms penicillin ml-1 and 100 U streptomycin ml-1, L-glutamine (0.29 mg ml-1), insulin (5 micrograms ml-1), transferrin (5 micrograms ml-1) and selenium (5 ng ml-1) for 12 h. Samples of the medium were harvested 10 min (basal concentration) and 2, 6 and 12 h after incubation to determine the concentrations of progesterone and prostaglandin.(ABSTRACT TRUNCATED AT 250 WORDS)