| Abstrakt: |
The effect of Ca on jejunal osmiophilic particles was studied in a recirculating system which was not contaminated with plasma lipoproteins. An isolated, infused segment of rat jejunum was suspended in a bath of liquid paraffin. Transudate, containing osmiophilic particles, appeared like beads of sweat on the serosal surface, and fell to the bottom of the bath. In the range of 25-38 C, 30 C proved to be optimal for histological preservation of villous architecture. Production of transudate, 20 mg/min/g of jejunum, and transport of [C] oleate proceeded nearly linearly after the first 30 min. Necrosis of mid-villus and crypt cells became obvious by light microscopy after one hour. Therefore, transudate was collected between the period of 30-60 min. Shadow casting of transudates, produced when saline was infused, revealed that 86±9 (SD) % of osmiophilic particles was <800 Å in diameter; 13±8% was 800-1000 Å; 0.4±0.5% was 1000-2000 Å. Corresponding values were 58±10, 25±5, and 16±5% when 5 mM [C] oleate+2.5 mM monoolein was infused; 75% of the transported [C] appeared in triglyceride. Adding 2 mM Ca to the infusion doubled the transport of [C] triglyceride without increasing particle size further. We conclude that luminal Ca increases the absorption of luminal fatty acid by rat jejunum in vitro. [ABSTRACT FROM AUTHOR] |
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