Ghrelin doesn't limit insulin release in pregnant rats fed low protein diet.

To test the hypothesis that insulin secretion in pregnant rats fed LP diet is reduced by ghrelin signaling in pancreatic islets,  we investigated plasma insulin levels, expression of ghrelin and its receptor and glucose stimulated insulin secretion (GSIS) of pancreatic islets in response to ghrelin. Plasma insulin levels were lower and ghrelin receptor abundance in islets was unaltered in LP rats. In the presence of both 2.8 and 16.7 mM glucose, GSIS was lower in LP compared to CT rats. In the presence of 2.8 mM glucose, GSIS was unaltered by ghrelin and its antagonist in both CT and LP rats. In the presence of 16.7 mM glucose, GSIS in LP rats was unchanged while in CT rats was reduced by ghrelin and reversed by ghrelin antagonist. These results indicate ghrelin signaling inhibits GSIS of pancreatic islets in pregnant rats fed CT diet, but it is blunted in pregnant rats fed LP diet and thus may not contribute to the reduction of plasma insulin and GSIS of pancreatic islets in late pregnancy.