Nursing Mice (IMAGE) Penn State Caption Shannon Kelleher, Penn State associate professor of cellular and molecular physiology and colleagues found that mice lacking the zinc transporter ZnT2 had reduced mammary gland development and severe defects in function during lactation. Credit Patrick Mansell, Penn State Usage Restrictions non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.