Somatomedin C and Arginine: Implicit Connections between Mutually Isolated Literatures (1990)

PERSPECTIVES IN BIOLOGY AND MEDICINE Volume 33 ¦ Number 2 · Winter 1 990 SOMATOMEDIN C AND ARGININE: IMPLICIT CONNECTIONS BETWEEN MUTUALLY ISOLATED LITERATURES DON R. SWANSON* The purpose of this review is to show how a synthesis of the arginine and somatomedin literatures can lead one to identify an important but neglected area of research, an area that ultimately might enhance our understanding of certain emaciating diseases and age-related degenerative processes. Hundreds of biomedical articles document the stimulatory effect of infused arginine on the release of growth hormone (GH) in humans. That GH in turn can stimulate the production of circulating somatomedin C (SmC) is equally well documented. One can plausibly infer that arginine intake may influence blood levels of SmC. In this article, I show that there are many additional reasons to believe that arginine may have such an effect and that increased SmC levels can have important health benefits. Remarkably, however, there are almost no published articles that explicitly mention the possible influence of arginine on SmC. The idea that the two literatures on arginine and SmC can be linked by implicit arguments yet have few or no articles in common may have This work is supported by U.S. Department of Education grant RA03980028 from the Office of Educational Research and Improvement—Library Research and Demonstration Program. The author thanks Richard L. Landau and Lewis S. Seiden for many helpful suggestions, and Daniel A. Albert for calling attention to the report listed as reference [4]. Space does not permit publishing the complete list of references. A supplementary list is available from the author. *Graduate Library School, University of Chicago, 1100 East 57th Street, Chicago, Illinois 60637.© 1990 by The University of Chicago. All rights reserved. 0031-5982/90/3302-0677$01.00 Perspectives in Biology and Medicine, 33, 2 ¦ Winter 1990 \ 157 more general significance. If two such nonintersecting literatures do not cite each other and are not cited together ("co-cited") by other articles, they are said to be "noninteractive." In that event, the possibility that the two literatures have not before been brought together and synthesized may be worth considering. One may hope, through such a synthesis, to bring to light unnoticed connections that cannot be seen in the two literatures considered separately. This paper is the third in a series published in Perspectives based on the idea of bringing together logically related noninteractive literatures [1, 2]. The first two papers have each examined one example of such a pair of literatures, the first example being on Raynaud's disease and dietary fish oils, and the second on migraine and magnesium. The implied connection for each of these examples has received some degree of independent clinical corroboration [3, 4]. The first example preceded by more than 18 months the first report of a clinical test ofdietary fish oil in Raynaud patients [1, 4]. The Somatomedin Hypothesis In 1957, Salmon and Daughaday reported that a substance in the serum of normal rats stimulated the incorporation ofsulfate by cartilage from hypophysectomized (hypox) rats, and that this same factor appeared in the plasma of hypox rats over a 24-hour period following treatment with GH [5]. However, GH added in vitro to cartilage had virtually no such effect. These experiments implied that the action of GH in stimulating the uptake of sulfate by rat cartilage was mediated by some other substance, which Salmon and Daughaday called a "sulfation factor." During the ensuing decade, the presence in serum of a GHdependent sulfation factor was confirmed by various laboratories; moreover , it became clear that the sulfation factor stimulated a broad range of anabolic processes; its biological action was not limited to cartilage, or to rats, or to the incorporation of sulfate. To denote the broader anabolic and growth implications, as well as the relationship to GH (somatotropin ), Daughaday, Hall, and other leading investigators in 1972 proposed the name "somatomedins" [6]. From experiments on glucose uptake in rat tissue, Hall concluded at about the same time that somatomedins were probably also the substance that caused "non-suppressible insulinlike activity" [7]. Several types of somatomedins eventually were isolated and sequenced under the name "insulin-like growth factors;" ofinterest here is insulin-like...