[In vitro studies on vitamin B6 serosa to mucosa flow in response to various concentrations of pyridoxine HCl in the serous solution].

In vitro experiments using everted sacs of the jejunum of rats weighing about 160 g were conducted to study the possibility of a flux of pyridoxine . HCl (PN . HCl) from the serosa to the mucosa. After an incubation of 45 min with 0, 2, 4, 10, 25, 50, 100, 200 or 500 micrograms PN . HCl per milliliter of serosal solution the transport of vitamin B6 into the intestinal wall and into the mucosal solution was measured. Between the concentration of PN . HCl of the serosal solution and the amount of vitamin B6 transported into the mucosal solution and into the intestinal wall, respectively, there existed a linear correlation in the tested range. In comparison to the serosal amount, the amount transported into the mucosal solution and into the intestinal wall, respectively, was constant when the concentration of PN . HCl in the serosal solution exceeded 25 micrograms PN . HCl per milliliter. Consequently a reflux of vitamin B6 from serosa to mucosa is principally possible, whereby this reflux would depend on a concentration gradient, however. THe possible role of this reflux in respect of maintaining homeostasis of vitamin B6 in the organism is discussed.