Postnatal development of the endocrine pancreas in mice lacking functional GABA B receptors

Adult mice lacking functional GABA B receptors (GABA B1 KO) have glucose metabolism alterations. Since GABA B receptors (GABA B Rs) are expressed in progenitor cells, we evaluated islet development in GABA B1 KO mice. Postnatal day 4 (PND4) and adult, male and female, GABA B1 KO, and wild-type littermates (WT) were weighed and euthanized, and serum insulin and glucagon was measured. Pancreatic glucagon and insulin content were assessed, and pancreas insulin, glucagon, PCNA, and GAD65/67 were determined by immunohistochemistry. RNA from PND4 pancreata and adult isolated islets was obtained, and Ins1, Ins2, Gcg, Sst, Ppy, Nes, Pdx1, and Gad1 transcription levels were determined by quantitative PCR. The main results were as follows: 1) insulin content was increased in PND4 GABA B1 KO females and in both sexes in adult GABA B1 KOs; 2) GABA B1 KO females had more clusters (