Studies in rats showed that the content and secretion of pancreatic secretory proteins were generally reduced during the
acute phase of pancreatitis, whereas a limited number of proteins were secreted in higher amounts. The most dramatic
increase was observed for pancreatitis-associated protein (PAP), which was merely detectable in control pancreas and
represented up to 5% of secreted protein at the climax of the acute phase. It was found that rat PAP induced extensive
bacterial aggregation in vitro, suggesting that it is involved in the control of bacterial proliferation and is an important
component in the defense against pancreatic aggression.Pancreatic-associated protein-III (PAPIII) is a member of a group of closely related, lectin-type proteins that are especially
abundant in the inflamed pancreas.The 3 rat PAP genes all map to chromosome 4 and are probably the result of a gene triplication
event.
General function
Comment
Cellular localization
Secreted
Comment
Ovarian function
Ovulation
Comment
In the ovary, Richards et al 2002 reported that
transcripts for PAPIII appear between 4 and 12 h after
administration of hCG, with peak levels at 8 h . In situ hybridization shows that PAPIII mRNA is most abundant in endothelial cells that line the inner walls of
blood vessels. It is interesting to note that PAPIII is also present in granulosa cells of some small follicles. The presence of
PAPIII in the blood vessels, especially those in the hilus of the ovary, provides additional evidence that ovulation is
comparable in some ways to an inflammatory reaction. In the ovulatory process, PAPIII may provide a protective role to
reduce trauma to the ovarian vasculature during the ovulatory period.
Expression regulated by
LH
Comment
Ovarian localization
Granulosa, Stromal cells
Comment
Yoshioka S, et al 2002 reveals that the ovulatory events include induction of mRNA for pancreatitis-associated protein-III (PAP-III). Immature Wistar rats were primed with 10 IU equine chorionic gonadotropin s.c., and 48 h later the 12-h ovulatory process was initiated by 10 IU human chorionic gonadotropin (hCG) s.c. Ovarian RNA was extracted at 0, 2, 4, 8, 12 and 24 h after the animals were injected with hCG. The RNA extracts were used for RT-PCR differential display to detect PAP-III gene expression in the stimulated ovarian tissue. Northern blotting showed that transcription was significantly greater at 4-12 h after the ovaries had been stimulated by hCG. In situ hybridization indicated that PAP-III mRNA expression was limited mainly to the hilar region of the ovarian stroma, with most of the signal emanating from endothelial cells that lined the inner walls of blood vessels, and from small secondary follicles. Treatment of the animals with ovulation-blocking doses of indomethacin (an inhibitor of prostanoid synthesis) or epostane (an inhibitor of progesterone synthesis) revealed that ovarian transcription of PAP-III mRNA was moderately dependent on ovarian progesterone synthesis. In conclusion, the present evidence of an increase in PAP-III gene expression in gonadotropin-stimulated ovaries provides further evidence that the ovulatory process is comparable to an inflammatory reaction.