[Toxicological and pharmacological effects of the use of bovine somatotropin in dairy farming].

Some possible toxicological and pharmacological consequences of the use of bovine growth hormone (BST) synthesised using recombinant DNA techniques are discussed in the present paper. Three spheres of interest are reviewed. Target species: When BST is used correctly, negative effects on the target species are unlikely to occur. Obscurity may to some extent remain as regards the effect of BST on the immune system. Residues of BST and IGF: There is nothing to suggest that the BST levels in the milk will increase significantly following BST treatment. Slight elevations of the levels of IGF-1 (one of the so-called somatomedins) in the milk following treatment with BST have been reported. However, the concentration of IGF-1 that is reached after the correct use of BST is still lower than that in milk collected during early stages of lactation. As a result of the peptide character of BST and IGF-1, absorption by healthy human individuals is unlikely to occur. The relevance of the problem of BST and/or IGF-1, absorption from milk by some individuals such as young infants is also discussed in this paper. Interaction with the metabolism of drugs: A possible interaction between BST and drugs which are administered to the animal at the same time, as is observed in rats and occasionally also in human subjects could have consequences for the clinical effectiveness, side-effects and drug residues in food products of animal origin. So far, however, an interaction of this type could not be detected in ruminants. At the present time, this phenomenon is being studied in greater detail.(ABSTRACT TRUNCATED AT 250 WORDS)