Figure 4.

The effect of fat explants on ER alpha expression in bovine mammary gland primary cell culture. The expression of ER alpha was examined in primary culture that was incubated with mammary fat explants (closed bars) or without mammary fat explants (open bars). Four treatments were introduced: three different levels of prolactin (0.01, 0.1, and 1 μg/mL) and one combined treatment of leptin antagonist (3200 ng/mL) and 1 μg/mL prolactin. The expression of ER alpha in primary culture incubated with no fat explants did not change in the same magnitude when compared to explants incubated with fat explants. A significant difference in the expression of ER alpha between the treatments containing fat explants and those without was observed at prolactin concentrations of 0.1 and 1 μg/mL prolactin. Leptin antagonist minimized the differences between the two treatments (with fat and without). Results are least square means ± S.E.M. of four independent experiments (n = 3). ∗, ∗∗ means differing at P < .05 and P < .001, respectively, between treatments with and without fat-explants.