the effects of ethanolic and aqueous extracts of rheum ribs l. (rr) of the family polygonaceae was studied on serum cholesterol concentration in rabbits. to induce hypercholesterolemia, 0.5 g/kg/day of pure cholesterol powder was given orally to each rabbit for two weeks then cholesterol was halved and each group of animals was treated with a different regimen for another two weeks. both the et...

The connexion between pellagra and maize consumption has occupied the interest of many workers for a number of years. It has been suggested that maize owes its pellagragenic property to an imbalance of amino-acids, tryptophan being especially low. This imbalance was said to increase the need for nicotinic acid (Krehl, Henderson, de la Huerga & Elvehjem, 1946; Krehl, 1949). The presence of a ‘to...

BACKGROUND Chronic UV skin exposure leads to epidermal differentiation defects in humans that can be largely restored by pharmacological doses of nicotinic acid. Nicotinic acid has been identified as a ligand for the human G-protein-coupled receptors GPR109A and GPR109B that signal through G(i)-mediated inhibition of adenylyl cyclase. We have examined the expression, cellular distribution, and ...

This work describes a medium-based screening method for selecting microbial biocontrol agents against Erwinia amylovora based on the degradation of a specific growth factor. Erwinia amylovora, the causal agent of the devastating fire blight disease, requires nicotinic acid or nicotinamide as an essential growth factor. Potential biocontrol agents are either selected for antimicrobial production...

The present study was prompted by the observation that ingestion of large amounts of nicotinic acid resulted in a relatively large increase in the apparent excretion of thiamine by human subjects maintained on a constant low intake of thiamine. Although the daily excretion of thiamine had been at a fairly constant level, between 20 and 30 y for several months, after administration of 300 mg. of...

Gobell (1) showed that 100 mg. of nicotinamide injected intravenously into children produced regularly a fall in the blood sugar level, averaging 21.3 mg. per cent. The hypoglycemic action of nicotinic acid was also observed in normal human adults by Marche and Delbarre (2), PoumeauDelille and Fabiani (3), and Neuwahl (4). In experiments with animals Ledrut (5) observed a marked decrease in the...

Experimental evidence indicates that an analogue of nicotinamide adenine dinucleotide in which the adenine moiety is replaced by 2,6-diaminopurine is formed when cultured mammalian cells are grown in the presence of 2,6diaminopurine. It is also likely that the corresponding analogue containing nicotinic acid is formed when both 2,6-diaminopurine and nicotinic acid are added to the culture medium.

Our studies indicate that sulfapyridine modifies the normal metabolism of a bacterium. Coenzymes inhibit the effect of sulfapyridine on the growth of staphylococcus in Knight's medium. Nicotinic acid does not interfere with the action of sulfapyridine under the same conditions. The possible relation of sulfapyridine, nicotinic acid, and coenzymes in relation to bacterial growth is discussed.

In 1945, Krehl et al. (1) observed that tryptophan and nicotinic acid were mutually interchangeable, within limits, in supporting the growth of rats. Since that time considerable evidence has accumulated which demonstrates the biosynthesis of niacin from tryptophan in the rat and other animals. Studies with Neurospora and mammals have demonstrated that the pathway from tryptophan goes through k...