Endogenous inhibitors

In addition to inhibitory chemicals which enter the plant from the external environment, many endogenous inhibitors appear to function as regulators of seed germination and plant growth and development. The interrelationships between endogenous inhibitors and growth promoters such as the auxins, gibberellins, and kinins remain to be elucidated. 

The growing list of endogenous inhibitors of angiogenesis holds great promise for therapeutic applications (Table 2). Substances most advanced in clinical development include Endostatin, Angiostatin, Interleukin-12, Thrombospondin, and Tumstatin. As... 

CART (cocaine- and amphetamine-regulated transcript) is a hypothalamic peptide that inhibits both normal and starvation-induced feeding when injected into cerebral ventricles of rats. CART is co-localized with the anorexigenic peptide a-melanocyte-stimulating hormone in neurons of the arcuate nucleus. Secretion of CART is stimulated by leptin and CART may be an endogenous inhibitor of food intake. 

It is perhaps not surprising that, sinee adenosine has been presented as an endogenous inhibitor of neuronal funetion with its antagonists, like theophylline, being stimulants (see Chapter 13), it should have been implieated in sleep induetion. 

P. Sathiyamoorthy, Identification of vanillic and p-coumaric acid as endogenous inhibitors of soybean seeds and their inhibitory effect on germination. J. Plant P/m-w/. /id 120 (1990). 

Changes in binding can occur in many situations. In some diseases, the concentrations of binding proteins may be altered, and accumulation of endogenous inhibitors of binding may occur. For example, in renal... 

Nye JS, Voglmaier S, Martenson RE, Snyder SH. Myelin basic protein is an endogenous inhibitor of the high affinity cannabinoid binding site in brain. J Neurochem 1988 50 1170-1178. 

Shenolikar, S. Protein phosphatase regulation by endogenous inhibitors. Cancer Biol. 6 219-227,1995. 

Inverse Relationship between Protease Inhibitors and Metastatic Ability. All proteases, apart from possibly CD, appear to be controlled by endogenous inhibitors. In theory, therefore, the ability of malignant cells to produce metastasis could depend not only on the levels of the specific protease, but also on the concentration of relevant endogenous inhibitors. Thus, the presence of high levels of protease inhibitors might inhibit metastasis, while low levels of inhibitors might enhance metastasis. An inverse relationship between a number of specific inhibitors and metastatic potential has now been shown. Some examples of this type of relationship include TIMP-1 in Swiss 3T3 cells (K4), cysteine protease inhibitors in mouse melanoma cells (R6), and an alpha-1-proteinase inhibitor in rat mammary carcinomas (N2). Furthermore, a newly described serine protease inhibitor, known as maspin, was found to be expressed less frequently in advanced human breast cancers compared with early cancers (Z2). 

Interferences in the mussel homogenates may be responsible, in part at least, for the low measured epoxidation activity. Properties of endogenous inhibitors in several insect preparations have been reviewed by Wilkinson and Brattsten (29). 

The ease of preparation, minimal endogenous inhibitor problems plus points 2, 4 and 5 above suggest that midge preparations may be a convenient, effective tool for insect MFO studies. 

J. E. O-GlcNAc modification is an endogenous inhibitor of the proteasome. Ceil 2003, 335, 715-725. 

Panfoli I, Musante L, Morelli A, Thellung S, Cupello A. (1997). Ca(2+)-ATPase pump forms and an endogenous inhibitor in bovine brain synaptosomes. Neurochem Res. 22(3) 297-304. 

Rommelspacher H, Nanz C, Borbe HO, Fehske KJ, Muller WE, Wollert U. (1980). 1-Methyl-beta-carboline (harmane), a potent endogenous inhibitor of benzodiazepine receptor binding. Naunyn Schmiedebergs Arch Pharmacol. 314(1) 97-100. 

O Reilly M, Boehm T, Shing Y, et al. Endostatin an endogenous inhibitor of angiogenesis and tumor growth. Cell 1997 88 277-285. 

Aigner, A., Juhl, H., Malerczyk, C., Tkybusch, A., Benz, C. C., and Czubayko, F. 2001. Expression of a truncated 100 kDa HER2 splice variant acts as an endogenous inhibitor of tumor cell proliferation. Oncogene 20 2101-2111. 

Protein inhibitor of NOS Unknown mechanism Endogenous inhibitor found in brain... 

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