Expression of human growth hormone in the milk of transgenic mice

Abstract
This study was conducted to determine if human growth hormone (hGH) could be produced in the milk of transgenic mice at high levels without adverse effects on growth and reproduction. Twenty‐four transgenic mice were generated carrying hGH coding sequences linked to a mouse whey acidic protein (WAP) promoter. Of 17 mice that gave rise to offspring hGH was detected in the milk of four with levels ranging from 65 ng/ml to 0.41 mg/ml. The high expressing line was propagated to generate homozygous offspring. These expressed hGH in milk at levels greater than 1 mg/ml. Although low levels of hGH were detected in serum during lactation in this line, growth and reproduction were normal. These results demonstrate the feasibility of producing commercially important levels of hGH in the milk of transgenic animals.