705 Prostaglandins (Pg) Stimulate Disaccharidase Activity in Adrenalectomized Suckling Rats

Abstract

Since pancreatic amylase (PA) i s absent in prematures, GP hyd r o l y s i s depends on a l t e r n a t e enzymes. To assess premature SA a s a PA surrogate we evaluated i t s production, acid r e s i s t a n c e and hydrolytic potency in a simulated oro-pharyngeal (OP), g a s t r i c ( 6 ) and i n t e s t i n a l ( I ) environment. SA was added tp4yield 1.1 u/ml of a "modular" formula containing 7 gm/dl of C GP with degrees of polymerization (DP) 18-29 glucose u n i t s . After an 0.25 min. OP phase the G-phase was i n i t i a t e d by d i l u t i o n with pepsin/HCl t o y i e l d pHs of 2, 3, 4, o r 5. After 5 min. o r 3 hours pH was adjusted t o 7.0 with cholate/trypsin chymotrypsin/Na CO ( I phase). After t h e OP-and G-phases and 15, 60 and 180 ~n ? n .~o f I-phase, oligosaccharides were separated by t h i n l a y e r chromatography. % breakdown=cpm i n DP 1-9 / cpm i n t o t a l sample x 100. Results: In 11 prematures SA a c t i v i t y was 1-33 u/ml; isozyme prof i l e d acid r e s i s t a n c e were i d e n t i c a l t o a d u l t SA. Substantial G-phase breakdown only occurred with 3 hour exposure a t pH 4 (12%) and 5 (32%). In t h e I-phase SA a c t i v i t y resumed. Prior Gphase pH a f f e c t s ultimate I-phase breakdown, p<.O01. (After 5 min. G-phase a t pH 2&5, I-phase breakdown = 8&25%; a f t e r 3 hour G-phase a t pH 2&5, I-phase = 17&55%.) Conclusion: The limited SA of premature s a l i v a can produce s i g n i f i c a n t GP digestion in both t h e stomach and small i n t e s t i n e . DEVELOPMENT OF GLUTAMINASE RU3ffi THE VILLUS-CRYPT AXIS OF RAT JFJUNUM. L.E. Nagy and N.' 704 Kretchmer. University of California,Berkeley, ~e p a r m ~u t r i t i o n a l Sciences.During the developnent of i n t e s t i n a l c e l l s , energy is required f o r a number of functions: mintenance of c e l l u l a r p r o l i f e r a t i o n , d i f f e r e n t i a t i o n and migration, and absorption and packaging of absorbed material. While glutamine is the m j o r f u e l source f o r the e n t i r e s m l l i n t e s t i n e , t h e u t i l i z a t i o n of glutamine during the development of the i n t e s t i n a l c e l l has not been described. W e have examined t h e regulation of glutaminase (EC 3.5.1.2), the e n t r y enzyme f o r glutamine metabolism, i n enterocytes i s o l a t e d along t h e villus-crypt a x i s from jejunum. S p e c i f i c a c t i v i t y of glutaminase, vrnol/mg protein/h, was 5.07r0.60 i n v i l l u s c e l l s (0-758 of the t o t a l p r o t e i n removed from jejunum), 6.07r1.29 i n the v i l l u s c r y p t junction c e l l s (75-958 of t o t a l p r o t e i n ) and 3.91 r0.80 i n c r y p t c e l l s (95-1008 of t o t a l p r o t e i n ) . Quantity of glutaminase p r o t e i n was determined by a d o t inmunobinding a s s a y using an antibody t o p u r i f i e d glutaminase.Imunoreac t i v e glutaminase-protein r e l a t i v e t o t o t a l c e l l p r o t e i n was 6.03r1.99 c p / ~g homogenate p r o t e i n i n v i l l u s c e l l s , 3.34fl.16 cpn/vg a t the villus-cryp...