Histidyl-proline diketopiperazine (His-Pro DKP) cells in the pancreas of human fetuses aged between 12 and 19 wk were localized by the indirect antibody-enzyme method on semithin sections. To study their fine structure, two techniques were used: a superimposition technique consisting of comparison of the same cells in semithin and electron microscopic preparations, and an immunocytochemical technique on ultrathin sections using the unlabeled antibody peroxidase-antiperoxidase method. Our results show that (a) the same cells are positive for both His-Pro DKP and glucagon/glicentin, (b) His-Pro DKP immunoreactive cells possess extremely electron-opaque secretory granules, implying that these cells correspond to the A cells, and (c) His-Pro DKP immunoreactivity is found over the secretory granules. We hypothesize that the two peptides His-Pro DKP and thyrotropin-releasing hormone (TRH) have independent origins, since TRH is found in the B cells.
P Leduque, I M Jackson, A Kervran, S Aratan-Spire, P Czernichow, P M Dubois
The Editorial Board will only consider comments that are deemed relevant and of interest to readers. The Journal will not post data that have not been subjected to peer review; or a comment that is essentially a reiteration of another comment.