Growth hormone stimulates islet B-cell replication in neonatal rat pancreatic monolayer cultures
Abstract
A possible role for growth hormone (GH) in stimulating islet B-cell replication was examined in neonatal rat pancreatic monolayer cultures.
Addition of ovine GH (1000 ng/ml) to serum-free medium for 2 days resulted in a significant increase (+114%) in [3H]thymidine labeling of B-cells in aldehyde-thionine-stained autoradiographs, and a similar increase in the B-cell mitotic index.
The stimulatory effects of GH on islet B-cell replication were greatest in serum-free medium, unaffected by glucose concentrations (2.8--16.7 mM), and not accompanied by any stimulation of insulin release.
The threshold concentration of GH for a significant stimulatory effect on B-cell replication was 30 ng/ml.
The insulin-like growth factor, multiplication stimulating activity (MSA), also effectively stimulated B-cell replication.
Although some effects of GH are mediated by the insulin-like growth factors (IGFs), the effects of GH on B-cell replication did not appear to be mediated by IGFs since (1) the maximal effect of GH (+156%) was significantly greater than that of MSA (+91%); (2) the combination of maximal stimulatory concentrations of GH and MSA produced an additive effect; and (3) a significant effect of GH on B-cell replication was observed as early (8 h) as that produced by MSA.
These results suggest that GH can stimulate islet B-cell replication directly, and that this effect may not depend on production of either insulin-like growth factors.
See also:
- Official Web Site: The Di Bella Method;
- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;
- The Di Bella Method (A Fixed Part - Bromocriptine/Cabergoline);
- The Di Bella Method (A Fixed Part - Cyclophosphamide and/or Hydroxyurea tablets, one or two per day);
- Pancreatic Adenocarcinoma: clinical records on 17 patients treated with Di Bella's Method;