Effect on carbohydrate systems

THE EFFECTS OF PLANT-GROWTH SUBSTANCES ON CARBOHYDRATE SYSTEMS... 

Hilton, H. W., The Effects of Plant-growth Substances on Carbohydrate Systems, 21, 377-430... 

Hibbert, Harold. See Evans, Taylor H. Hickson, John L. See Clamp, John R. Hilton, H. W., The Effects of Plant-growth Substances on Carbohydrate Systems, 21, 377—430 Hindert, Marjorie. See Karabinos, J. V. Hirst, E. L., [Obituary of] James Col-quhoun Irvine, 8, xi —xvii Hirst, E. L., [Obituary of] Walter Norman Haworth, 6, 1—9... 

Although it is generally recognized that the thyroid secretions exert a profound effect on carbohydrate metabolism in animal tissues, no clear-cut evidence is available which would implicate a member of the glycolytic system in the chain of events by which the hormone exerts its effect on the organism. 

The incorporation of heteroatoms can result in stereoelectronic effects that have a pronounced effect on conformation and, ultimately, on reactivity. It is known from numerous examples in carbohydrate chemistry that pyranose sugars substituted with an electron-withdrawing group such as halogen or alkoxy at C-1 are often more stable when the substituent has an axial, rather than an equatorial, orientation. This tendency is not limited to carbohydrates but carries over to simpler ring systems such as 2-substituted tetrahydropyrans. The phenomenon is known as the anomeric ect, because it involves a substituent at the anomeric position in carbohydrate pyranose rings. Scheme 3.1 lists... 

Triiodothyronine (3, 5,3-L-triiodothyronine, T3) is a thyroid hormone. It is producedby outer ring deiodination of thyroxine (T4) in peripheral tissues. The biologic activity of T3 is 3-8 times higher than that of T4. T3 is 99.7% protein-bound and is effective in its free non-protein-bound form. The half-life of triiodothyronine is about 19 h. The daily tur nover of T3 is 75%. Triiodothyronine acts via nuclear receptor binding with subsequent induction of protein synthesis. Effects of thyroid hormones are apparent in almost all organ systems. They include effects on the basal metabolic rate and the metabolisms of proteins, lipids and carbohydrates. 

Some reports even indicate that the conjugation of proteins or peptides with carbohydrates can increase dramatically their activity compared to that of the native state (Susaki et al., 1998). Carbohydrates also can provide a protective effect on modified peptides toward proteolytic digestion (Rudd et al., 1994) or mask recognition of a peptide by the immune system (Harding et al., 1993). The creation of neoglycoproteins thus can affect the activity of peptides and proteins, which are not normally glycosylated in vivo. 

Physioiogicai There is an extensive literature that deals with the effects ginseng on CNS function, but effects are also seen in neuroendocrine function, carbohydrate and lipid metabolism, the immune system, and cardiovascular function (Gillis 1997). Ginsenosides induce a decrease in heart rate and have biphasic effects on blood pressure, with decreases preceded by a slight increase (Kaku et al. 1975). Ginsenoside Rgl had the most potent effects on blood pressure. Little or no effect is observed on respiration. 

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