What is so unique about hormone action?

Abstract

Some fundamental principles of cellular regulation have emerged from work on the mechanism of action of hormones. For example, the discovery of cyclic AMP and the subsequent realization of the importance of protein phosphorylation as a major cellular regulatory process stem directly from Sutherland’s efforts to elucidate how adrenaline and glucagon control glycogen metabolism (Sutherland, 1972). The recognition of the central role played by the movement of calcium into and out of cells (Berridge, 1980) in numerous cellular and physiological functions also owes its origins to investigations of hormonal control of calcium distribution. To some extent, our present knowledge about the organization and transcription of eukaryotic genes can be attributed to investigations on the regulation of gene activity by steroid hormones, as illustrated by the expression of genes coding for egg proteins (O’Malley et al., 1979; Tata and Smith, 1979). In the light of these advances a view has often been expressed that there is something unique or special about how hormones act, as can be judged from the vast literature and multitude of national and international conferences and workshops currently devoted to this subject (Tata, 1984). I examine here the validity of such a tenet by considering historical, evolutionary and phenomenological observations relevant to hormone action. I shall argue that, whereas it is important to study hormone action as a means to exploring general principles of biological regulation, unique mechanisms of hormonal regulation do not exist and it is therefore futile to search for such principles. Important characteristics of hormone action