15.5. 1976

Specialia

613

Drug Interactions in Intestinal Absorption of 3H-Digitoxin in Rats W.

BRAUN

and

K. I t . DAMM

Department o/ Pharmacology, University o/Hamburg, Martinistrasse 52, D-2000 Hamburg 20 (German Federal Republic, BRD), 12 November 1975. Summary. T h e a b s o r p t i o n of 3 H - d i g i t o x i n f r o m p e r f u s e d r a t s m a l l i n t e s t i n e was i n h i b i t e d b y p r o b e n e c i d (1.0 • 10 -~ M), e t h a c r y n i c acid (0.5 • 10 -3 M), a n d m e r s a l y l (8.0 • 10 -a M ) i n d i c a t i n g t h a t d i g i t o x i n a b s o r p t i o n is a t l e a s t p a r t l y a n a c t i v e process. I n r e c e n t studies o n t h e in v i t r o a b s o r p t i o n of digit o x i n , t h e c o n t r i b u t i o n of a n a c t i v e t r a n s p o r t was ass u m e d b y t h e following f i n d i n g s : s a t u r a b l e a n d u p h i l l t r a n s p o r t f r o m m u c o s a t o serosa ~; d e p e n d e n c y o n o x y g e n a n d e n e r g y s u p p l y 2 ; a n d f u n c t i o n a l a s y m m e t r y conc e r n i n g m u c o s a l a n d serosal a d m i n i s t r a t i o n of d i g i t o x i n 3. M o r e o v e r t h e a b s o r p t i o n of a H - d i g i t o x i n was i n h i b i t e d b y p r o b e n e c i d , e t h a c r y n i c acid, a n d m e r s a l y l 2. T h e p r e s e n t s t u d y h a s b e e n p e r f o r m e d in o r d e r to i n v e s t i g a t e t h e d r u g effects o b t a i n e d ill v i t r o on t h e i n t e s t i n a l abs o r p t i o n of 3 H - d i g i t o x i n in v i v o in rats.

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