Somatostatin (SRIF) acts on specific membrane: receptors to inhibit ex
ocrine and endocrine pancreatic functions. Five SRIF receptor genes ha
ve been cloned, producing six receptor proteins (sst-s). We used a rec
ently developed antibody to localize the sst2A splice variant in the r
at pancreas. Western blots identified the sst2A. receptor as an 90 kDa
glycosylated protein in pancreatic tissue. In tyramide-amplified immu
nostainings all acinar cells, and the glucagon and pancreatic polypept
ide immunoreactive cells (A and PPI respectively) were intensely label
ed for sst2A, while no signal was detected in SRIF producing (D) cells
. A very few insulin immunoreactive (B) cells were also labeled for ss
t2A, but the signal in these cells was lower than in exocrine, A or PP
cells. Absorption of the sst2A antibody with the receptor peptide abo
lished specific staining in both immunoblots and tissue sections (nega
tive control). These studies are the first to localize any SRIF recept
or subtype in the rat pancreas. The specific localization of sst2A rec
eptor in acinar, A and PP cells if confirmed in humans, would suggest
that subtype specific analogs will be useful for the therapeutic relat
ion of exocrine and/or endocrine pancreatic secretion.