1. Cellular Endocrinology Unit, University Department of Clinical Biochemistry, Royal Infirmary, Edinburgh EH3 9YW, U.K.,
2. Department of Applied Nutrition and Food Chemistry, Chemical Centre, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden,
3. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB, U.K.