DIGESTIVE LIPASES OF THE NEWBORN FERRET - COMPENSATORY ROLE OF MILK BILE SALT-DEPENDENT LIPASE

The amount of mRNA hybridizing to bile salt-dependent lipase and to co lipase-dependent lipase probes as well as their translation into activ e proteins were quantified in the adult and newborn pancreas and lacta ting mammary gland from the ferret, a species whose milk, similar to t hat of the human, has bile salt-dependent lipase. The concentration of colipase-dependent lipase mRNA correlated with the amount of activity found in the adult and newborn pancreas, whereas neither mRNA nor act ivity of this enzyme was detected in the kit pancreas or in the lactat ing mammary gland. These data indicate that colipase-dependent lipase is actually expressed in adult pancreas and might represent the main l ipolytic system in the adult. mRNA hybridizing to the bile salt-depend ent lipase probe used in this study were detected in adult and in newb orn ferret pancreas as well as in lactating mammary gland. However, th e bile salt-dependent lipase activity expressed in the newborn pancrea s was very low when compared with the activity expressed either in the mammary gland or in the adult pancreas. These data argue for a compen satory role of milk as bile salt-dependent lipase in lipid digestion i n the newborn. The hydrolysis of dietary fat might be initiated by pre duodenal lipase, the activity of which is only two times lower in the gastric mucosa of the newborn than in the adult ferret. The high conce ntration of mRNA hybridizing to the bile salt-dependent lipase probe a ssociated with a very poor bile salt-dependent lipase activity and pro tein suggests either that these mRNA are very unstable or that they ar e poorly translated into an active pancreatic bile salt-dependent lipa se.