Growth factor

Epidermal growth factor (EGF)b 6,400 Epithelial and mesodermal cells 

Platelet-derived growth factor (PDGF)b 31,000 Same 

Nerve growth factor (NGF)C 13,000 Sensory and sympathetic neurons 

Macrophage colony-stimulating factor (M-CSF or CSF-l)b 70,000 (dimer) Macrophage precursors 

Granulocyte colony-stimulating factor (G-CSF) 25,000 Granulocyte precursors 

The preponderance of B. bifidum in the faeces of breast-fed infants is due to the presence of stimulatory factors in human milk. The most important of these are N-acetylglucosamine-containing saccharides, referred to as bifidus factor I, which is present at high levels in human milk and colostrum and bovine colostrum but at very low concentrations in the milk of cows, goats and sheep. Human milk also contains several non-dialysable bifidus-promoting factors which are glycoproteins, referred to as bifidus factor II. Many of the glycoproteins have been isolated and characterized (see Fox and Flynn, 1992). 

Bifidobacterium spp. are also stimulated by lactulose, a derivative of lactose (Chapter 2) which is not related to bifidus factors I and II. 

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A great number of various substituted aminophenyl derivatives of thiazolium, and their organic or metallic complexes, have been patented as weed-killers or regulating growth factors of plants (135-138). 

Lipoic acid a growth factor required by a variety of different organisms... 

Bacteria require p-aminobenzoic acid to biosyn thesize folic acid a growth factor Structurally sul fanilamide resembles p-aminobenzoic acid and is mistaken for it by the bacteria Folic acid biosynthesis IS inhibited and bacterial growth is slowed suffi ciently to allow the body s natural defenses to effect a cure Because animals do not biosynthesize folic acid but obtain it in their food sulfanilamide halts the growth of bacteria without harm to the host... 

Bone disease Bone growth factor Bone imaging Bone marrow... 

Antibiotics (qv) have been fed at subtherapeutic levels to promote mminant animal growth. Possible reasons for the observed growth include decreased activity of microbes having a pathogenic effect on the animal, decreased production of microbial toxins, decreased microbial destmction of essential nutrients, increased vitamin synthesis or synthesis of other growth factors, and increased nutrient absorption because of a thinner intestinal wall... 

One possible mechanism responsible for the abiHty of trenbolone acetate to stimulate skeletal muscle hypertrophy may be through enhanced proliferation and differentiation of satelHte ceUs as the result of increased sensitivity to insuHn-Hke growth factor-I (IGE-1) and fibroblast growth factor (43). 

SEM = standard error of the means. IGF-I = insulin-like growth factor I. 

Cytokines, eg, interferons, interleukins, tumor necrosis factor (TNF), and certain growth factors, could have antitumor activity directiy, or may modulate cellular mechanisms of antitumor activity (2). Cytokines may be used to influence the proliferation and differentiation of T-ceUs, B-ceUs, macrophage—monocyte, myeloid, or other hematopoietic cells. Alternatively, the induction of interferon release may represent an important approach for synthetic—medicinal chemistry, to search for effective antiinflammatory and antifibrotic agents. Inducers of interferon release may also be useful for lepromatous leprosy and chronic granulomatous disease. The potential cytokine and cytokine-related therapeutic approaches to treatment of disease are summarized in Table 4. A combination of cytokines is a feasible modaUty for treatment of immunologically related diseases however, there are dangers inherent in such an approach, as shown by the induction of lethal disserninated intravascular coagulation in mice adrninistered TNF-a and IFN-y. 

Ah = Antibody IL = interleukin TNF =tumornecrosis factor INF = interferon LAK =lymphocyte-activated killer CSF =colony stimulating factors and FGF = fibroblast growth factor. 

Cytokines and Immunophilins. A large number of inflammatory mediators and related proteins including the cytokines, colony stimulating factors (CSFs), interferons (IFNs), tumor necrosis factors (TNFs), growth factors (see Growth regulators), neurotrophic factors, and immunophilins are found in the mammalian CNS and appear to play a significant role in CNS function both in development and in aspects of brain homeostasis (40—43). 

Insulin and Amylin. Insulin is a member of a family of related peptides, the insulin-like growth factors (IGFs), including IGF-I and IGF-II (60) and amylin (75), a 37-amino acid peptide that mimics the secretory pattern of insulin. Amylin is deficient ia type 1 diabetes meUitus but is elevated ia hyperinsulinemic states such as insulin resistance, mild glucose iatolerance, and hypertension (33). Insulin is synthesized ia pancreatic P cells from proinsulin, giving rise to the two peptide chains, 4. and B, of the insulin molecule. IGF-I and IGF-II have stmctures that are homologous to that of proinsulin (see INSULIN AND OTHER ANTIDIABETIC DRUGS). 

Derivatives. Scopoletin [92-61-5] (6-methoxyumbeUiferone) (38) occurs, for example, in Solanaceae as a growth factor in plants. Primin [15121 -94-5] (2-methoxy-6-pentyl-l,4-benzoquinone) is a skin irritant isolated from Primula ohconica. Versicolin [4389 4-0]... 

Amino acids are the main components of proteins. Approximately twenty amino acids are common constituents of proteins (1) and are called protein amino acids, or primary protein amino acids because they are found in proteins as they emerge from the ribosome in the translation process of protein synthesis (2), or natural amino acids. In 1820 the simplest amino acid, glycine, was isolated from gelatin (3) the most recendy isolated, of nutritional importance, is L-threonine which was found (4) in 1935 to be a growth factor of rats. The history of the discoveries of the amino acids has been reviewed... 

Many kinds of amino acids (eg, L-lysine, L-omithine, t-phenylalanine, L-threonine, L-tyrosine, L-valine) are accumulated by auxotrophic mutant strains (which are altered to require some growth factors such as vitamins and amino acids) (Table 6, Primary mutation) (22). In these mutants, the formation of regulatory effector(s) on the amino acid biosynthesis is genetically blocked and the concentration of the effector(s) is kept low enough to release the regulation and iaduce the overproduction of the corresponding amino acid and its accumulation outside the cells (22). 

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