The concentrations and hormonal forms of CCK and VIP have been determined in extracts of the brain and duodenum of the developing and adult pig. In methanol extracts of the brain cortex, the single hormone form, CCK8, increased from 130 +/- 20 (Mean +/- SEM) pmol/g at birth to an adult level of 300 +/- 50 pmol/g. In acid extracts of brain, the predominant immunoreactive form had N-terminal immunoreactivity and increased from 240 +/- 20 pmol/g at birth to an adult level 490 +/- 30 pmol/g; the C-terminal immunoreactivity was about 10-fold lower. The concentrations and hormonal forms of immunoreactive CCK in duodenal extracts did not appear to be age-related. C-terminal immunoreactivity in methanol extracts averaged 140 +/- 20 pmol/g and in acid extracts 240 +/- 60 pmol/g. The concentration of N-terminal immunoreactivity in acid extracts averaged 490 +/- 70 pmol/g. The VIP concentrations in acid extracts of the brain cortex was 13.5 +/- 2 pmol/g at birth and rose gradually to 30 +/- 9 pmol/g in the adult; in duodenal extracts it was 240 +/- 18 pmol/g at birth and 195 +/- 38 pmol/g in the adult. These results are in marked contrast with the ontogeny of these hormones in the rat in which brain concentrations of CCK and VIP in the neonate are less than 10% of adult levels and in which there are age-related changes in the content of these hormones in the duodenum as well.

Aging↗

PubMedDate not supplied

Purification and sequencing of a rat intestinal 22 amino acid C-terminal CCK fragment.

Fractionation on Sephadex G50 gel of methanol extracts of rat intestine revealed two molecular forms of cholecystokinin (CCK) of about equal immunopotency: one form has an elution volume between CCK33 and CCK12; the other elutes in the salt region as does authentic CCK8. Purification and sequencing have demonstrated that the smaller molecular form is CCK8 with a sequence identical to the pork and sheep CCK8's that had previously been sequenced. Purification and sequencing of the larger molecular form reveals that it is a 22 amino acid C-terminal CCK fragment identical with pig CCK22 except that glycine instead of serine is present at the nineteenth residue from the C-terminus. This sequence is consistent with that predicted by cloned cDNA encoding preprocholecystokinin from a rat medullary thyroid carcinoma. CCK22 has not previously been reported to be a prominent molecular form in either pig or dog intestines.

Amino Acid Sequence↗

PubMedDate not supplied

Unique cholecystokinin peptides isolated from guinea pig intestine.

Fractionation on Sephadex G50 gel of methanol extracts of guinea pig intestine reveals two molecular forms of cholecystokinin (CCK) of about equal abundance. One elutes at the position of CCK8 while the other elutes at a position intermediate between CCK33 and CCK8. Purification and sequencing of these peptides identify them as CCK8 and CCK22, respectively. Guinea pig CCK8 differs from other mammalian CCK octapeptides isolated thus far in that there is a valine substituted for methionine at position 6 from the C-terminus. In addition to the substitution in CCK8, serine is substituted for asparagine in position 22, glycine for serine in position 19, and asparagine for serine in position 15 from the C-terminus compared to the pig sequence. HPLC separation on a C18 column yields two peaks each of CCK8 and of CCK22 in pig intestinal tissue obtained from a commercial supplier. The two CCK8 peptides have identical amino acid sequences as do the two CCK22 peptides. The CCK22 peptides are equally bioactive in the guinea pig pancreatic acinar cell assay but are about 10-fold less potent than synthetic CCK8(s). One of the guinea pig CCK8 peptides is fully bioactive whereas the other is about 50-fold less potent compared to synthetic CCK8(s).

Amino Acid Sequence↗

PubMedDate not supplied

Sequences of gastrins purified from a single antrum of dog and of goat.

Heptadecapeptide gastrins (G17) have been purified and sequenced from a variety of species. However, progastrin (G34) sequences have been determined only for pig and human from purified peptides and for rat from cDNA. Since G34 in most species accounts for only approximately 5% of total antral gastrin, micropurification techniques must be employed to avoid the need for large quantities of antral tissue. Efficient purification methodology yielded 1.5 and 1.3 nmol of G34 from the antrum of a single goat and of a single dog, respectively. The N-terminal pyroglutamyl residues were enzymatically removed and the peptides were sequenced through to the proximity of their COOH-termini. The COOH-terminal sequences of goat and dog G34 were confirmed by sequencing the corresponding deblocked G17 from each animal. The previously published dog G17 sequence was shown to be incorrect. The sequences for dog and goat G34 are: Dog less than ELGLQGPPQLVADLSKKQGPWMEEEEAAYGWMDF# Goat less than ELGLQDPPHMVADLSKKQGPWVEEEEAAYGWMDF# Dog and goat gastrins differ in 3 sites in the 17 amino acid NH2-terminus and only a single site in G17 (the sites of differences are underlined). The ratio for sulfated to non-sulfated antral G17 is 9:1 for the goat and 1:9 for the dog.

Amino Acid Sequence↗

PubMedDate not supplied

Guinea pig pancreatic polypeptide: structure and pancreatic content.

Guinea pig (GP) pancreatic polypeptide (PP) has been purified from an acid-alcohol extract of 6 GP pancreata by a series of 3 HPLC steps. The sequence for GP PP as compared with that of beef and human is shown: (Sequence: see text). In a single GP pancreas weighing 2.4 g the total PP content was 1.0 nmol and the total glucagon content 61 nmol; in a single dog pancreas weighing 35 g the total PP was 385 nmol and the total glucagon 81 nmol. The relatively low content of PP in GP pancreas is consistent with the fact that the GP lacks a ventral pancreas, the region in which PP is found in highest concentration. The high glucagon content of GP pancreas is consistent with that reported in earlier studies.

Amino Acid Sequence↗