Activity distribution of seven digestive enzymes along small intestine in calves during development and weaning.

Ten groups of calves were used to study the changes in activity levels and distribution of seven hydrolases in the intestinal mucosa during development and weaning. The calves in the first group were sacrificed at birth while those in the remaining nine groups were either milk-fed until slaughter on days 2, 7, 28, 56, 70, and 119; or weaned between days 28 and 56 and then slaughtered on days 56, 70, and 119, respectively. The small intestine was immediately cut off and divided into five segments, ie, duodenum, proximal jejunum, median jejunum, distal jejunum, and ileum.

Cloning and nucleotide sequence of a bovine pancreatic preprocarboxypeptidase A cDNA.

A full-length cDNA clone encoding bovine pancreatic preprocarboxypeptidase A was isolated and sequenced. The 1405-base pair insert contains a 26-nucleotide 5'-noncoding region, a 1260-nucleotide open reading frame and a 76-nucleotide 3'-noncoding fragment plus a poly(A) tail of at least 43 nucleotides. The open reading frame encodes a protein of 419 amino acids, including the 16 amino acid signal peptide.

Isolation and nucleotide sequence of cDNA clone for bovine pancreatic anionic trypsinogen. Structural identity within the trypsin family.

A cDNA clone encoding an anionic form of bovine trypsinogen was isolated from a pancreatic cDNA library. The corresponding 855-nucleotide mRNA contains a short 5' noncoding region of 8 nucleotides and a long 3' noncoding region of 56 nucleotides in addition to a poly(A) tail of at least 50 nucleotides. The deduced amino acid sequence for the anionic pretrypsinogen (247 residues) includes the N-terminal 15-amino-acid signal peptide followed by an 8-amino-acid activation peptide.

Specific regulation of the gene expression of some pancreatic enzymes during postnatal development and weaning in the calf.

The construction of cDNA library from calf pancreas allowed us to examine the mRNA levels of four pancreatic hydrolases (chymotrypsin, lipase, trypsin and amylase) during postnatal development in preruminant and ruminant animals. The lack of parallel variations in the levels of the enzyme specific activities suggested that protein synthesis was not coordinately regulated. In preruminant calves, the change in chymotrypsin and lipase mRNA concentrations (0-28 day period) and in trypsin mRNA concentrations (0-119 day period) was opposite to that in the corresponding specific activities.

[Modulation of pancreatic chymotrypsin messenger RNA during post-natal development and weaning in calves].

Levels of chymotrypsin mRNA in the pancreatic tissue of preruminant calves were significantly decreased on d 28 and to a lesser extent on d 119 as compared to those of newborns. Enzymic activity regularly increased during the same period. By contrast, both chymotrypsin-specific activity and the mRNA level in the ruminant animals were enhanced on d 119 (1.