$164

of up to 5ug/100g BW produced no significant trend of effects on hepatic portal insulin and glucagon levels or on peripheral GH levels. These data provide a basis for future studies characterizin~ the physiological proper- ties and possible interactions of these peptides and also indicate the importance of blood glucose levels in interpreting effects of gastrointestin- al peptides. The feasibility of structure-activity studies is also indica- ted by the secretin, VIP, and GIP results which demonstrate that the partial dissociation of biological actions of these closely related, naturally occurring peptides might be further exploited synthetically to produce phar- macologically useful compounds. This work supported by NIH AM 30167.

IMPORTANCE OF HUMORAL CONTROL OF NUTRIMENT-INDUCED PANCREATIC POLYPEPTIDE SECRETION IN THE CAT. D. Rigaud, T. Cheval ier, C. Cut r i , J.P. Accary, M. Dubrasquet. INSERM U.IO (Pr. S. Bonf i ls ) Hop. Bichat, F-75877 Paris Cedex 18.

Neural regulat ion of pancreatic polypeptide (PP) secret ion appears to be predominant in several species and man, but humoral controls do ex i s t . In another species, the cat, our purpose was to invest iga te central neural PP release and to appreciate the PP response to nutr iments. Six adult cats provided w~th gast r ic f i s t u l a and Heidenhain pouch received in random order: I00 mg.kg of deoxyglucose (2DG) i . v . bolus, or d i f f e ren t nutriments admi- nistered by i n t r agas t r i c route in a f i na l volume of 60 ml: mixed l i v e r (50 g) and i t s components: ol igopept ides (3 and 9 g), t r i g l y c e r i d e s (2 g), glycogen (2 g). The humoral s t imulat ion of the gast r ic secretion was measur- ed by the Heidenhain-pouch acid secret ion. Blood was drawn for PP determina- t ion at -15, +15, +30, +60, +90 min a f te r s t imula t ion . Our plasma PP radioimmunoassay was val idated in cat ( d i l u t i on curves and recovery). Basal PP level was 28 ~ 2 p m o l . l - ' .

No s i g n i f i c a n t PP release was observed Fat and carbohydrates are weak st imulants,

Nutriments APP (151min) APP (90 min) Peak H~ 1 (pmol. )* ( p m o l . l - ) * (~mol .15min)*

Mixed l i v e r " 108 + 16 50 + 17 94 + 15

Oligopeptides 3 g 87 + 31 64 + 29 67 + 5 9 g 93 ¥ 24 35 ¥ 15 120 ¥ 23

Tr ig lycer ides 31 ± 12 17 ± 8 < 5 *M~SEM

a f te r glycogen admin is t ra t ion. proteins were the most potent

st imulant fo r PP secret ion, as in other species. PP response to 2DG was 17 % of response to the l i v e r . In these cats, central PP release and humoral regulat ion were pointed out.

INTESTINAL PHASE OF PANCREATIC POLYPEPTIDE. RELEASE BY CHOLECYSTOKININ. Gerald M. Fried, W. David Ogden, George Greeley, James C. Thompson. Dept of Surg, The Univ of Texas Medical Branch, Galveston, TX 77550 USA.

Postprandial release of pancreatic polypeptide (PP) is biphasic, with an initial phase probably dependent on cholinergic stimulation and a second, "intestinal" phase, probably stimulated by gut hormones. We studied the intestinal phase of PP release in order to evaluate the correlation between plasma concentrations of PP and cholecystokinin (CCK) (measured by specific radioimmunoassays) in the presence and absence of cholinergic (vagal) inner- vation. Methods. Five dogs with duodenal fistulas received a continuous 2-hr