Regulation of Bile Formation in Rabbits and Guinea Pigs

Abstract

Despite interruption of the enterohepatic circulation of bile salts, bile flow in conscious rabbits and guinea pigs remained constant for several hours when saline was infused to compensate for loss of water and electrolytes in bile. Thus it appeared that biliary flow in these species is not as highly dependent on bile salt secretion as it is in dogs and man. The effects of other stimulants known to play an important role in regulating bile formation in other species were tested in rabbits and guinea pigs. Secretin, cholecystokinin-pancreozymin (CCK-PZ) and gastrin proved to be ineffective choleretics in rabbits although the doses of these exogenously-administered hormones were sufficient to siguificantly increase either pancreatic or gastric secretion. Trivial choleretic responses were recorded after administration of secretin and CCK-PZ to guinea pigs. Attempts were then made to elicit a choleresis by release of endogenous hormones. Again no changes in bile formation were recorded in rabbits although pancreatic secretion was stimulated. Bile flow in guinea pigs increased slightly, but the degree of duodenal acidification necessary to produce all of these responses to endogenous secretin release was probably unphysiological. Attempts to stimulate the release of endogenous CCK-PZ by infusing peptone were unsuccessful. It was concluded that if these herbivores do elaborate secretin and CCK-PZ, the factors responsible for their release may differ from those in other species. The present findings provide further evidence that the control of bile formation in rabbits and guinea pigs differs from that in other species, and it is possible that these differences could be related to the temporal pattern of their eating habits.According to Sperber [1965], bile secretion in many species is mainly due to active secretion of bile salts into the canaliculi and the subsequent osmotic flow of water. However, the primacy of bile salt secretion in the regulation of bile flow of herbivores such as rats and rabbits has been questioned by Klaassen [1972] and Erlinger, Dhumeaux, Berthelot and Dumont [1970]. Gastrointestinal hormones, particularly secretin, may also be important in the regulation of bile formation in dogs [Jones, Geist and Hall, 1971], cats [Scratcherd, 1965] and man [Konturek, Dabrowski, Adamozyk and Kulpa, 1969]. However, it would appear from the small amount of information existing on the subject, that herbivores, at least the non-ruminant type, may be relatively insensitive to the effects of gastrointestinal hormones [Scratcherd, 1965;Shaw and Heath, 1972]. It has been suggested that the failure of secretin to act as a choleretic agent in rabbits may be associated with the very high spontaneous rate of bile formation in this species [Scratcherd, 1965].The present study was designed to provide more information on the regulation of bile formation in conscious rabbits and guinea pigs, two species which have the highest rates of bile formation known.

Ursodeoxycholate-induced choleresis in taurine-deprived and taurine-supplemented rats.

“…In rabbits, at least, the rise in bicarbonate concentration in the bile is not an unusual phenomenon specific to ursodeoxycholate but has been found with other bile salts such as taurodeoxycholate (RUTISHAUSER and STONE, 1975), deoxycholate, and chenodeoxycholate (MIYASAKA and KITANI, 1983). If such a secretory mechanism is operative for bile salts other than ursodeoxycholate, it helps explain many difficult questions on "bile-salt-dependent bile," that is, the variability of the slope value between different bile salts (SHAW and HEATH, 1974;KITANI and KANAI, 1981), different animal species (WHEELER and RAMOS, 1960;BERTHELOT et al, 1970;ERLINGER et al, 1970;BOYER and BLOOMER, 1974;SHAW and HEATH, 1974;REICHEN and PAUMGARTNER, 1977), and in the same animal with the different experimental conditions (RUTISHAUSER and et al, 1977;KITANI and KANAI, 1982 …”

“…between bile flow and the bile salt excretion rate was found in most past studies (WHEELER and RAMOS, 1960;ERLINGER et al, 1970;BERTHELOT et al, 1970;BOYER and BLOOMER, 1974;SHAW and HEATH, 1974;REICHEN and PAUMGARTNER, 1977;KITANI and KANAI, 1981), and the slope of the straight line calculated from the relation between these two parameters was believed to express the capacity of each bile salt to form bile water osmotically.…”

“…However, the variability of the slope value between different bile salts (SHAW and HEATH, 1974;KITANI and KANAI, 1981) and different animal species (WHEELER and RAMOS, 1960;BERTHELOT et al, 1970;ERLINGER et al, 1970;BOYER and BLOOMER, 1974;SHAW and HEATH, 1974;REICHEN and PAUMGARTNER, 1977) has not been convincingly explained. Furthermore, Balabaud and coworkers (BALABAUD et al, 1977) reported that even with the same bile salt (taurocholate) in the same animal, the slope value can vary l0-fold when the relation is examined over a wide range of bile salt excretion rates.…”

Effets de la prise alimentaire sur la sécrétion biliaire chez le lapin

“…Les données relatives à la sécrétion biliaire chez le lapin anesthésié sont aussi abondantes (Esteller, Lopez et Murillo, 1977 ;Klaassen, 1973 ;Rutishauser et Stone, 1975 ;Scratcherd, 1965). Toutefois, les informations disponibles sur la sécrétion biliaire chez l'animal éveillé sont plus restreintes (Esteller, Jiménez et Lopez, 1981 ;Shaw et Heath, 1974) Murillo, 1977 ;Klaassen, 1973 ;Shaw et Heath, 1974).…”

Effect of pentobarbital or urethane on bile secretion and chemical composition of blood in the rabbit

“…In the present work two such substances widely used in the field of experimental physiology, sodium pentobarbital and ethyl urethane, were examined in an attempt to determine to what extent bile secretion and composition as well as the chemical composition of blood varies in rabbits with excluded gallbladder. In this animal species, owing to the difficulties in maintaining a chronic biliary fistula (Shaw & Heath, 1974;DiPadova et al, 1981;Esteller, Jimenez & Lopez, 1981;Jimenez, Esteller & Lopez, 1982), most studies have been carried out on animals anaesthetized with one of these agents (Klaassen, 1974;Rutishauser & Stone, 1975;Shaw & Heath, 1975;Bruss, Cornelius & Himes, 1983;Gonzalez et al, 1983;Esteller et al, 1984;Zahavi, Shaffer & Gall, 1985).…”