Summary
In this study we investigated the effect of human amniotic fluid (HAF) on the incorporation
of 3H-thymidine into cultured rat islets. The addition of 1% HAF (1% HAF, 99% TCM) did
not alter the incorporation of labeled thymidine, in comparison to TCM 199 alone (100%).
The culture in the presence of 50% HAF (1:1 diluted with TCM, v/v) resulted in a significantly
increased DNA synthesis. To exclude any effect of ionic composition or substrate dilution
by the HAF, the TCM 199 was also either diluted (1:1) with saline or Hank's balanced
salt solution (HBSS). Islets cultured under these conditions did not show any stimulated
thymidine incorporation into islet DNA. From these results we conclude that HAF contains
an activity which stimulates islet replication.
In order to concentrate this stimulatory activity, HAF was tested after it had been
lyophilized or evaporated. Independent of the method used, in no case a stimulatory
effect of concentrated HAF was found. In contrast, the concentrated form of HAF inhibited
the incorporation of labeled thymidine into islet DNA.
Key Words
Human amniotic fluid - DNA synthesis - Rat pancreatic islets - Islet culture