Hormonal control of protein deposition in animals.

The hormonal control of protein deposition in animals is a highly integrated process. Consideration of this topic not only requires a study of hormonal interactions with target tissues but also the much more general topic of growth. Growth itself is a complex and integrated process and involves the formation and enlargement of many metabolic units. Obviously maximal protein deposition in an animal only occurs when the overall status of the animal favours anabolism. In this review the production of protein for export from the tissues, e.g. hair, milk and eggs, will not be considered. The production of milk and egg protein is subject to considerable hormonal control and will be considered elsewhere in this Symposium. As pointed out by Young (1980) protein metabolism is intimately affected by, and related to, the status of carbohydrate and lipid metabolism in the whole organism and these aspects of metabolism are also subject to considerable hormonal control. A detailed evaluation of the many reports of the effects of a wide variety of hormones on the many facets of protein metabolism is not possible in the space available but instead an attempt will be made to consider those aspects which are relevant to the manipulation of the hormonal status of animals. No attempt will be made to present a catalogue of the effects of various hormones and hormone-like substances on growth and carcass composition, this has recently been reviewed by Galbraith & Topps (1981); nor will any attempt be made to review in detail the neuro+mdocrinological control of hormone secretion, an area in which considerable advances are to be expected during the next decade.