Pantothenic acid actions/effects

A sparing effect of large amounts of ascorbic add fed to pantothenic acid-defident rats has been known since the work of Daft (D2, D3), although no such effect occurs in guinea pigs (R7). It is believed that alteration of the bacterial flora of the intestine lessens the pantothenic acid deficiency under these conditions because it has been demonstrated that the antibiotic hygromycin acted in the same way as ascorbic acid, while sulfathiazole nullified the beneficial effect of ascorbic acid (B12). Pyrocatechol intensifies the beneficial action of ascorbic acid (L5). 

Other fractions of the vitamin B complex have also been tested for their effect on the survival of young adrenalectomized rats, and it was found that biotin was as effective as pantothenate (Ralli and Dumm, 1952). This is interesting in view of the previous discussion of the interrelation of biotin and pantothenic acid (see Section V.b). In this same series of experiments it was observed that large doses of pyridoxine were toxic to adrenalectomized rats when given after a period of pantothenate deficiency. Thiamine and riboflavin had no influence on survival, but folic acid and vitamin Bu resulted in a moderate improvement. These observations emphasize the interaction of vitamins under various nutritional situations in relation to hormone action. 

Sodium 2,2-dichloropropionate (dalapon, Dowpon ) is much used for killing grass in dicotyledonous crops such as beet and lucerne. Competitive studies in bacteria E. coli) point to its being an antagonist for the incorporation ofpantoic acid [i.e. the left-hand side of 9.38)] into pantothenic acid. This is the main site of its action on grasses its effect is diminished by external pantothenic acid Hilton et al., 1959). 

Daily intraperitoneal administration of pantothenic acid (100 mg/kg) for 5 days conferred significant protection against the peroxidative actions of a 0.5 ml/kg intraperitoneal dose of CCh in rats (Nagiel-Ostaszewski and Lau-Cam 1990). lipid peroxidation by incubation of Ehrlich ascites tumour cells with FeClj -i- HjOj was partly prevented by preincubation with D-pantothenate, 4 -phospho-pantothenate, D-pantothenol, or pantethine (Sly-SHENOv et al. 1995). Rats exposed to y radiation from a Co source, receiving 0.25 Gy at weekly intervals were protected from the deleterious effects by 26 mg pantothenol/kg x day given for 2 d before each irradiation (Slyshenov et al. 1998). 

However, the latter assumption can not be the only mechanism of action, because pantothenic acid did not exert so favorable effect on the diabetic hyperlipidemia as pantethine ( data not shown ). And some additional action of pantethine should be considered. This has been also supported by the present finding that pantethine did not stimulate COo formation from 1- C-palmitate in the absence of added CoA ( Figs.3 and 4 ). There may be several... 

Since the antibiotin factor does not inhibit those bacteria which synthesize biotin, the antibiotin factor appears to combine only with the externally supplied biotin and cannot penetrate effectively to the sites of biotin synthesis and utilization. This is analogous to the findings with the synthetic inhibitory growth factor analogs (e.g., pyrithiamin and thiamin, pantoyl taurine and pantothenic acid, pyridine-2-sulfonamide and nicotinamide) where the inhibitory action is largely confined to those otgan-isms which do not synthesize the growth factor. 

---