Journal: Cell reports

Article Title: Paracrine inhibition via G protein inwardly rectifying potassium channels regulates glucagon secretion from human pancreatic alpha cells

doi: 10.1016/j.celrep.2026.117068

Figure Lengend Snippet: (A) Perifusion experiments of dynamic glucagon secretion showing responses to step decreases in glucose concentration. Data plotted as fold change over baseline release at 5 mM (5G; n = 5–10 nondiabetic donors). (B) Quantification of glucagon responses shown in (A) (area under the curve [AUC], min 40–96). (C) Glucagon secretion in response to prolonged low glucose showing a gradual decline. Data plotted as fold change over baseline (5G; n = 13 nondiabetic donors). For comparison, changes in glucagon secretion elicited by sequential glucose steps from 11G to 7G and 7G to 1G are shown (gray). (D) Quantification of glucagon secretion shown in (C) at 0, 60, and 90 min in low glucose (1G; plotted as percentage of peak response). (E) Glucagon secretion in response to specific stimulation with epinephrine (Epi; 10 μM) ± forskolin (Fsk,1 μM) in low glucose (1G) for 90 min, followed by membrane depolarization with KCl (30 mM). Data plotted as fold change over baseline (5G) from a representative nondiabetic donor. (F) Quantification of glucagon secretion shown in (E) as AUC (minutes 124–154, n = 4–8 nondiabetic donors). (G) Glucagon secretion in response to opening K ATP channels with diazoxide (1 or 100 μM; DZ 1 or DZ 100) after prolonged exposure to low glucose (1G, 120 min). Data plotted as fold change over baseline (5G; n = 7 nondiabetic donors). (H) Quantification of glucagon secretion shown in (G) in response to diazoxide (AUC, min 132–156). (I and J) Glucagon and insulin secretion during dynamic perifusion in response to a reset period of 5, 15, or 30 min in high glucose (17G). Data normalized to minimum (at 17G) and maximum (at 1G) responses (%, average responses do not reach 100% because peaks do not synchronize; n = 5 nondiabetic donors). (K) Quantification of peak glucagon response after reset period shown in (I) and (J). Data are presented as mean ± SEM throughout the paper; * p < 0.05, ANOVA followed by multiple comparisons in (F), (H), and (K) and one-sample t test to compare the mean to 0 (B).

Article Snippet: To assess glucose-stimulated hormone release of human pancreatic islets, 120–150 human islets were placed in perifusion columns (Biorep Technologies, Cat# PERI-CHAMBER) and connected to an automated perifusion system.

Techniques: Concentration Assay, Comparison, Membrane

Journal: Cell reports

Article Title: Paracrine inhibition via G protein inwardly rectifying potassium channels regulates glucagon secretion from human pancreatic alpha cells

doi: 10.1016/j.celrep.2026.117068

Figure Lengend Snippet: (A) Perifusion experiments of dynamic glucagon secretion showing responses to somatostatin (SST; 1 μM) and serotonin (5HT; 10 μM). Data plotted as fold change over baseline release at 5 mM (5G; n = 10 nondiabetic donors). (B) Quantification of glucagon responses shown in (A). Dotted line indicates baseline glucagon secretion at 5G. Time points indicated in (A) show significant inhibition of glucagon secretion (1 and 3) and rebound response (2 and 4) to the paracrine stimulus. (C) Glucagon secretion in response to SST (1 μM) or 5HT (10 μM) in low glucose (1G). Data plotted as fold change over baseline release at 5G ( n = 6 nondiabetic donors). (D and E) Glucagon secretion in response to SST (1 μM), 5HT (10 μM), or γ-aminobutyric acid (GABA; 100 μM) after prolonged exposure to low glucose (1G, 90 min). Data normalized to minimum (at 5G) and maximum (at 1G) responses (%). (F) Quantification of glucagon peak responses during the rebound phase at min 160–180 shown in (D) and (E). Dotted line indicates glucagon levels in the absence of paracrine stimulation. (G) Glucagon secretion in response to high (17G) and low glucose (1G) of islets from nondiabetic donors and donors with long T1D duration (see and for donor characteristics). Data plotted as fold change over baseline release at 5G ( n = 5 nondiabetic and 3 T1D donors). (H) Continuation of glucagon secretion from isolated islets of T1D donors shown in (G) in response to 5HT (100 μM), SST (1 μM), or GABA (100 μM). Data plotted as fold change over baseline release (5G; n = 4 T1D donors). * p < 0.05; one-sample t test to compare the mean to the mean of basal secretion at 5G (1 in B) and to the mean of control at minutes 160–180 (13.3% in F).

Article Snippet: To assess glucose-stimulated hormone release of human pancreatic islets, 120–150 human islets were placed in perifusion columns (Biorep Technologies, Cat# PERI-CHAMBER) and connected to an automated perifusion system.

Techniques: Inhibition, Isolation, Control

Journal: Cell reports

Article Title: Paracrine inhibition via G protein inwardly rectifying potassium channels regulates glucagon secretion from human pancreatic alpha cells

doi: 10.1016/j.celrep.2026.117068

Figure Lengend Snippet: (A) Perifusion experiments of dynamic glucagon secretion showing responses to GIRK channel blockade with tertiapin-Q (TPQ; 200 nM) or activation with ML-297 (10 μM). Data plotted as fold change over baseline release at 5 mM (5G; n = 5 nondiabetic donors). (B) Quantification of glucagon responses shown in (A) (area under the curve [AUC], min 14–47). (C) Glucagon secretion (relative to glucagon secretion at minute 32) in response to glucose step from 5G to 17G in control conditions and in the presence of TPQ (data are from experiment shown in A). (D) Quantification of glucagon responses shown in (C) (AUC, min 32–53). (E) Glucagon secretion in response to GIRK channel blockade with TPQ (200 nM) or activation with ML-297 (10 μM) after a glucose step from 5G to 1G ( n = 4–5 nondiabetic donors). (F) Quantification of glucagon responses shown in (E) (AUC, minutes 40–80). (G) Glucagon secretion (relative to glucagon secretion at time 62 min) in response to glucose step from 1G to 17G in control conditions and in the presence of TPQ (data are from experiment shown in E). (H) Glucagon secretion in response to GIRK channel blockade with TPQ (200 nM) or activation with ML-297 (10 μM) after extended low-glucose exposure (1G; 120 min; n = 8 nondiabetic donors). (I) Quantification of glucagon responses shown in (H) (AUC, min 132–160). (J) Glucagon secretion (relative to glucagon secretion at minute 130) in response to TPQ and ML-297 (data are from experiment shown in H). * p < 0.05; one-way ANOVA followed by multiple comparisons in (B), (F), and (I); Student’s t test in (D); two-way ANOVA (mixed-effect analysis) followed by multiple comparisons to control values in (A), (E), (G), and (J).

Article Snippet: To assess glucose-stimulated hormone release of human pancreatic islets, 120–150 human islets were placed in perifusion columns (Biorep Technologies, Cat# PERI-CHAMBER) and connected to an automated perifusion system.

Techniques: Activation Assay, Control

Journal: Cell reports

Article Title: Paracrine inhibition via G protein inwardly rectifying potassium channels regulates glucagon secretion from human pancreatic alpha cells

doi: 10.1016/j.celrep.2026.117068

Figure Lengend Snippet: (A) Perifusion experiments of dynamic insulin secretion showing responses to GIRK channel blockade with tertiapin-Q (TPQ, 200 nM) or activation with ML-297 (10 μM). Data plotted as fold change over baseline release at 5 mM (5G, insulin was measured in the recording shown in ; n = 5 nondiabetic donors). (B and C) Zoom in on the first 30 min of the recording shown in (A) demonstrating that, at 5 mM glucose concentration, insulin secretion does not change (B), while glucagon secretion changes dramatically (C; same as in shown here for illustration). (D) GIRK channel activity does affect high-glucose (17 mM)-stimulated insulin secretion.

Article Snippet: To assess glucose-stimulated hormone release of human pancreatic islets, 120–150 human islets were placed in perifusion columns (Biorep Technologies, Cat# PERI-CHAMBER) and connected to an automated perifusion system.

Techniques: Activation Assay, Concentration Assay, Activity Assay