[Direct stimulatory action of blood serum, vitamin D3, and its hydroxy-analogs on calcium transport in the small intestine of chicks in vitro].

A study was made of the effect of blood serum, vitamin D3 and its hydroxy-analogs (25-hydroxyvitamin D4. 1 alpha-hydroxyvitamin D3) on Ca2+ transport across the wall of the noninverted small sac of D-avitaminosis chicken during incubation in vitro. It was shown that blood serum from chickens fed vitamin D3 in different doses (50--20 000 IU) and at varying time (1--72 h) before sacrifice produced a marked stimulating action on the cation transport 10 min after administration into the intestinal cavity as compared with the effect produced by the serum from D-avitaminosis chickens. Administration into the intestine of vitamin D3 or its hydroxy-analogs in physiological doses (6.25--25.0 ng) also significantly stimulated Ca+ transport over 10 min of incubation.