Trypsin inhibition in serum and urine of neonatal and lactating rats and in rat colostrum and milk

Levels of the serum lipoproteins (HDL, LDL and VLDL) and lipids in the fetal, neonatal and pregnant rat were measured using electrophoretic, immunological and biochemical methods. The results were compared to those of the adult rat. In the fetal rat at the end of gestation, the lipoprotein pattern was dominated by LDL (β-lipoprotein). Fetal HDL (α-lipoprotein) occurred at a low concentration and showed a lower proportion of cholesterol and a higher proportion of triglycerides than did HDL in the adult rat serum. VLDL (pre-β-lipoprotein) was present only at very low concentrations. The lipoprotein pattern of suckling neonatal rats showed rapidly increasing levels of VLDL and LDL, and high serum lipid values during the first 2 weeks after birth. The lipoprotein pattern of the adult rat, with the HDL fraction dominating, was completely developed by about 4 weeks after birth. In rats during late pregnancy, very high serum values were found for VLDL and LDL. High levels of triglycerides associated with these fractions were also seen. The serum lipoprotein development of the fetal and neonatal rat is different from that reported for the pig and man. This focuses the interest on the differences in lipid and lipoprotein metabolism between species during ontogenic development.

Section: Experimental a Nimals And Collection O F Samplesmentioning

confidence: 99%

Lipoproteins and Lipids in Fetal, Neonatal and Adult Rat Serum

Johansson¹

1983

“…In many species, an important ingredient of colostrum and milk are the protease inhib itors. Sow's colostrum, for example, contains the specific protease inhibitor SCTI in high amounts (7-8 IU/ml), which has been shown to enhance the transmission of proteins from colostrum to blood serum of the piglet [Jensen and Pedersen, 1979;Westrom et al, 1985], Rat colostrum, however, exhibits a low inhibiting capacity the first 12 h of lacta tion, but the level increases in the milk to approximately 1 IU/ml, which is maintained throughout most of the lactating period [Carlsson et al, 1975], Our results imply that the presence of protease inhibitors in the gut of the preclosure rat increases the availabil ity of proteins in the small intestine and thereby makes the transmission of these molecules more effective. However, it is not clear whether the natural protease inhibition of rat milk, which is lower than the inhibi tion in the experimentally fed test solutions added with inhibitors (7.5 IU/ml), is suffi cient to exert this effect in the suckling rat.…”

Section: Discussionmentioning

confidence: 99%

“…In the rat, this macromolecular transmission lasts 3 weeks. Rat milk has a relatively low protease inhib iting capacity [Carlsson et al, 1975] com pared with the ungulates, and IgG could escape degradation by binding to the recep tors.…”

Section: Introductionmentioning

confidence: 99%

Intestinal Macromolecular Transmission in the Young Rat: Influence of Protease Inhibitors during Development

Telemo

Weström²,

Ekström³

et al. 1987

Intestinal macromolecular transmission in young rats of 10, 14, 18, 22 and 30 days of age was measured as the blood serum levels of markers 6 h after oral feeding of a solution containing bovine IgG (BIgG), bovine serum albumin (BSA) and fluorescein-isothiocyanate-labeled dextran 70,000 (FITC-D), either alone (controls) or with soybean trypsin inhibitor (SBTI) or swine colostrum trypsin inhibitor (SCTI). In the 10- and 14-day-old rats, transmission of all three macromolecular markers was high, with a preference for IgG. Transmission was greatly reduced by the age of 18 days and totally arrested for the protein markers at 22 days, with a low transmission of FITC-D remaining at 30 days of age. Addition of either of the two protease inhibitors significantly elevated the transmission of the protein markers in the rats aged 10, 14 and 18 days, while the transmission of the protease-independent marker FITC-D was unaffected. From 14 days of age, the rats have a functioning intestinal proteolysis, since only small amounts of marker proteins were left in the gut lumen 6 h after feeding, and since the addition of protease inhibitors resulted in increased amounts of undegraded proteins intraluminally. The results indicate that the increase of intraluminal proteolytic activity during development and the presence of protease inhibitors in the food are of importance for the intestinal transmission of undegraded proteins in the young rat. The Fc receptor for IgG in the enterocyte is not sufficient to maintain an optimal transmission of IgG, since the intraluminal proteolytic activity also appears to be of importance.

“…Sow colostrum, in contrast to rat colostrum/milk [3] contains high amounts of a specific trypsin-chymotrypsin inhibitor, the function of which appears to be to protect ingested proteins from gastrointestinal pro teolysis, thereby enhancing the nonselective protein absorption in the neonatal piglet [4, 17. 28].…”

Section: Discussionmentioning

confidence: 99%

Proteolytic Activity as a Regulator of the Transmission of Orally Fed Proteins from the Gut to the Blood Serum in the Suckling Rat

Telemo¹,

Weström²,

Karlsson³

1982

14-day-old rats were orally fed with porcine colostrum or serum having a low or high activity of protease inhibitors (i.e., sow colostrum trypsin-chymotrypsin inhibitor or soybean trypsin inhibitor). The uptake of undigested porcine albumin and IgG to the blood serum of these rats was studied 4 h after feeding. The effect of the exclusion of proteases to the intestinal lumen by means of pancreatic duct ligation prior to feeding was also studied. The results from these feeding experiments in the presence of protease inhibitors or in the absence of pancreatic proteases agreed well. It was concluded that for the suckling rat the intraluminal proteolytic activity in the gastrointestinal tract is a regulator for nonselective protein uptake, as represented by albumin, while the selective absorption of IgG was unaffected.