1. Division of Endocrinology and Metabolism (Á.G.-L., H.d.J., R.H.N., P.P.d.W., W.v.D., J.B., R.W.S.), Utrecht University, 3584 CH Utrecht, The Netherlands
2. Division of U-Protein Express B.V. (W.H.), 3584 CH Utrecht, The Netherlands
3. Department of Biology, Faculty of Science, Utrecht University, and U-Protein Express B.V. (W.H.), 3584 CH Utrecht, The Netherlands
4. Department of Physiology of Growth and Reproduction in Fish (G.L.T., R.W.S.), Institute of Marine Research, 5817 Bergen, Norway