Mammary Fat Can Adjust Prolactin Effect on Mammary Epithelial Cells via Leptin and Estrogen

Figure 1

Effects of leptin, prolactin, and estrogen on beta-lactoglobulin expression in explants from mammary glands of lactating cows. Mammary-gland explants from lactating cows were incubated for 4 days in media containing various treatments: prolactin at 1 𝜇g mL^-1, leptin at 50 ng mL^-1, a combination of leptin and prolactin, and a combination of leptin and estrogen at 200 ng mL^-1. Expression of the beta-lactoglobulin gene was evaluated by real-time PCR. Leptin alone elevated beta-lactoglobulin expression to a level of 1.2 arbitrary units, a level, which was not significantly different from that with insulin alone. Medium containing prolactin elevated beta-lactoglobulin expression to a level of 1.8 arbitrary units. When leptin and prolactin together were added to the medium, the level of beta-lactoglobulin reached 2.3 arbitrary units. Addition of estrogen to medium containing leptin and prolactin augmented the beta-lactoglobulin expression to 2.9 arbitrary units. Least squares means ± SE (n = 3). Bars with different letters differ at P < .05.