The pancreas of Syrian golden hamsters. Age-related autoradiographic observations.

We examined the effects of aging on the uptake of tritiated thymidine (3H-TdR) by the different cell types of the pancreas of the Syrian golden hamster. Animals, 8-22-wk-old, received 3H-TdR (2 microCi/gm) intraperitoneally and were sacrificed 1 h later. Pancreatic tissue from each animal was processed for autoradiography. The percentage of acinar cells labeled with 3H-TdR was 1.17 +/- 0.26 at 8-wk-old and steadily diminished to 0.02 +/- 0.00 at 22 wk. The percentage of ductular and islet cells labeled with 3H-TdR at 8 wk was 0.24 +/- 0.24 and 0.16 +/- 0.01, respectively and at 22 wk was 0.13 +/- 0.09 and 0.18 +/- 0.01, respectively. In contrast with acinar cells, the percentage of ductular and islet cells labeled with 3H-TdR between 10- and 20-wk-old showed considerable variability. In the major ducts in the head of the gland, the number of epithelial cells per mm duct length labeled with 3H-TdR did not change throughout the study; 3.25 +/- 1.5 at 8 wk and 3.35 +/- 1.3 at 22 wk. It is concluded that acinar cell growth is an inverse function of age between 8-22 wk and that differentiated cell types in the pancreas of the Syrian golden hamster are capable of incorporating 3H-TdR during the S-phase of the cell cycle.