9 . Recombinant bovine somatotrophins

Somatotrophins are proteins secreted by the anterior pituitary gland that stimulate growth, cell regeneration and reproduction in humans and animals. Most anabolic and growthpromoting effects of somatotrophins are mediated through insulin-like growth factor-I (IGFI). Bovine somatotrophins (bSTs) produced by recombinant deoxyribonucleic acid (DNA) techniques (rbSTs) are used in lactating dairy cows to increase milk production. Four bST analogues (somagrebove, sometribove, somavubove and somidobove) were previously evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) at its 40th Meeting (JECFA, 1993 [TRS 832]) and further evaluated at its 50th Meeting (JECFA, 1999 [TRS 888]). Although the chemical properties of the recombinant products vary slightly from those of pituitary bST (for chemical structures, see FAO, 1993), the Committee considered the recombinant products to be biologically and toxicologically similar, as they all act by binding with high affinity to the bST receptor.