Relationship between circulating vitamin D3 metabolites and prolactin or growth hormone levels in rat.

Previous studies (Haug & Gautvik 1985) have demonstrated specific receptors for 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in a clonal (GH3) strain of rat pituitary tumour cells. It was discovered that 1,25(OH)2D3 affected the production of prolactin and growth hormone in these cells in a calcium dependent manner. These findings were the basis for a hypothesis that vitamin D3 could be involved in the regulation of pituitary hormones in vivo.

Reduced carnitine and ketogenesis in the pivampicillin treated rat.

Pivampicillin (630 mg/kg body wt) given daily by stomach tube induced carnitine deficiency in the rat. The carnitine concentrations after 24 days were significantly reduced to (mean +/- SD) 34 +/- 2, 27 +/- 7, 70 +/- 18, 75 +/- 16 and 49 +/- 4% of controls in plasma, liver, muscle, heart and kidney, respectively, without any further reduction after 36 days. Pivampicillin treatment reduced the carnitine concentrations in the liver of the 48 hr fasted rat to about 1/2 of the controls after 6 days.

Radioimmunotargeting of human tumour cells in immunocompetent animals.

A tumour model system is reported that for many purposes may be an alternative to xenografted nude mice. The model allows immunotargeting of human tumour cells in immunocompetent animals. The target cells are contained in i.

The inhibitory effect of bile on the binding of vitamin B12 to intrinsic factor. An in vivo study in rats.

To investigate whether bile reduces the amount of vitamin B12 bound by intrinsic factor (IF) in the intestinal juice in vivo, choledochocolic fistulae were made in 9 rats, and 10 rats were sham-operated. Small-intestinal juice was collected 1 h after gastric instillation of 57CoB12. The percentage of 57CoB12 bound by IF in the intestinal juice was markedly increased in fistula rats (median, 86%; range, 75-91%) as compared with sham-operated rats (35%; 12-50%) (p less than 0.

Effect of calcium deficiency on vitamin B12 absorption in rats.

The influence of calcium on vitamin B12 absorption was investigated in two experiments. In the first we investigated whether B12 malabsorption in rats with biliary diversion through choledochocolic fistula is caused by deficiency of calcium in the small intestine. Calcium concentrations were measured in 10 fistula- and 10 sham-operated rats.