What receptors detect blood glucose levels?

Glucagon binds a GPCR on liver and muscle cells called the glucagon receptor, which then stimulates the cells to release glucose into the bloodstream. Another hormone involved in glucose control is called glucagon-like peptide-1 (GLP-1). It works by binding to another GPCR, the GLP-1 receptor, on cells in the pancreas.

How does glucose enter a beta cell?

Glucose enters β-cells by facilitated diffusion through glucose transporters (GLUT1 and 2). While this process is not limiting in β-cells [6], the next irreversible step, glucose phosphorylation, is catalyzed by a single enzyme, glucokinase (GK).

How does glucose signal insulin release?

Glucose elicits rapid insulin release through an adenosine triphosphate‐sensitive K+ channel (KATP channel)‐dependent mechanism, which is gradually augmented in a KATP channel‐independent manner. Biphasic GSIS thus occurs.

How do alpha cells detect glucose levels?

Glucagon secretion has been linked to several triggers: the α-cell detecting a fall in circulating glucose levels directly, a paracrine response to signal(s) from the islet β-cell (e.g., insulin, γ-aminobutyric acid [GABA], or Zn2+ ions) or the islet δ-cell (somatostatin), or a response to neural signals (2–8).

Why is glucose sensing important in the β cell?

Thus, the glucose-sensing mechanism of the β-cell is essential for maintenance of glucose homeostasis.

How are glucose sensing mechanisms in hypothalamic cell lines?

Novel orexigenic hypothalamic cell lines are glucose inhibited. Neuropeptide AgRP transcription and secretion are inhibited by glucose. Glucose sensing involves regulation of Akt, AMP-kinase, and nNOS. Glucose regulates AgRP secretion through CFTR and nNOS.

How is glucose transported across the β cell membrane?

There are three main characteristics of cytosolic glucose metabolism in the β-cell. First, glucose can equilibrate rapidly across the β-cell membrane due to the expression of the high capacity, low affinity glucose transporter-2 (Newgard & McGarry 1995).

Which is a glucose-inhibited ( GI ) cell model?

As models of glucose-inhibited (GI) neurons, mHypoE-29/1 and mHypoA-NPY/GFP cells express the essential orexigenic neuropeptide AgRP and glucose sensing machinery. Exposure to increasing concentrations of glucose or the glucose analog 2-deoxyglucose (2-DG) results in a decrease in AgRP mRNA levels.