Journal: bioRxiv

Article Title: Female resistance to the metabolic benefits of protein restriction is reversed by ovariectomy in mice

doi: 10.64898/2026.03.31.715667

Figure Lengend Snippet: (A) ANCOVA of energy expenditure (EE) with body weight as a covariate during the 12-hour dark cycle. (B) Average EE during the dark cycle normalized to body weight. (C) Respiratory Exchange Ratio (RER) over a 24-hour period. (D) Average RER during the dark cycle. (E) Spontaneous activity over a 24-hour period. (F) Average spontaneous activity during the dark cycle, calculated as laser beam breaks. (G) Circulating FGF21 expression quantified from refed plasma using ELISA. (H) The mRNA expression of Fgf21 in the liver of mice. (A-F) n=11-12 mice per group, (G-H) n=3-5 mice per group. (A) Data for each individual mouse is plotted, simple linear regression (ANCOVA) was calculated to determine if the slopes or elevations are equal. (B, D, F-H) Statistics for the overall effects of diet, gonadectomy, and the interaction represent the p value from a two-way ANOVA. *p<0.05 from a Šidák’s post-test examining the effect of parameters identified as significant in the two-way ANOVA. Data are represented as mean ±SEM. Abbreviations: CTL (21% control protein diet), LP (7% low protein diet), Cast (castration), Fem (female), Ovx (ovariectomy), BW (body weight), EE (energy expenditure), RER (respiratory exchange ratio), FGF21 (fibroblast growth factor 21).

Article Snippet: Blood for circulating FGF21, testosterone, and estradiol levels was collected from submandibular bleeding immediately prior to euthanasia; plasma was assayed with a mouse/rat FGF21 quantikine ELISA kit (MF2100) from R&D Systems (Minneapolis, MN, USA), and testosterone (582701) and estradiol (501890) quantikine ELISA kits from Caymen Chemicals (Ann Arbor, MI, USA).

Techniques: Activity Assay, Expressing, Clinical Proteomics, Enzyme-linked Immunosorbent Assay, Control

Journal: Frontiers in Endocrinology

Article Title: Metformin increases glycolysis and the stress-induced cytokine GDF15 but not FGF21 in humans

doi: 10.3389/fendo.2026.1797525

Figure Lengend Snippet: Effect of metformin on circulating GDF15 and FGF21. (a) Serum GDF15 (b) and serum FGF21 in healthy individuals fasted for 42 h without (white) and with (black) prior metformin (MET) treatment for seven days. Data is given in mean +/- SEM. #p<0.0001.

Article Snippet: FGF21 was measured on fasting serum samples by the human FGF21 Quantikine ® ELISA assay essentially as described (R&D Systems, Abingdon, UK).

Techniques:

Journal: Frontiers in Endocrinology

Article Title: Metformin increases glycolysis and the stress-induced cytokine GDF15 but not FGF21 in humans

doi: 10.3389/fendo.2026.1797525

Figure Lengend Snippet: Metformin increases mRNA levels of GDF15 in human intestinal Caco-2 cells with no related increase in FGF21. Relative mRNA expression of GDF15, FGF21, SLC2A1 , and the ISR genes ATF4 and DDIT3 in differentiated Caco-2 cells after (a) 6 h or (b) 22 h without treatment (0 mM) or 0.3 mM, 1 mM, or 3 mM metformin treatment at media glucose concentrations of 5.5 mM (c) Raw ct values of GDF15 and FGF21 at 5.5 mM glucose. n = 6-8, 2 wells from 4 independent experiments evaluated in parallel. The data is presented as mean +/- SEM. **p<0.01, ***p<0.001, and ****p<0.0001 as indicated.

Article Snippet: FGF21 was measured on fasting serum samples by the human FGF21 Quantikine ® ELISA assay essentially as described (R&D Systems, Abingdon, UK).

Techniques: Expressing

Journal: Frontiers in Endocrinology

Article Title: Metformin increases glycolysis and the stress-induced cytokine GDF15 but not FGF21 in humans

doi: 10.3389/fendo.2026.1797525

Figure Lengend Snippet: GDF15 secretion is increased in Caco-2 cells upon chronic metformin treatment. (a) GDF15 concentration in media collected from non-treated (0 mM) Caco-2 cells kept in media with glucose concentrations of 5.5 mM, 11 mM, or 25 mM or from cells treated with 0.3 mM, 1 mM, or 3 mM metformin at similar glucose concentrations. (b) A schematic representation of metformin-stimulated GDF15 secretion from Caco-2 cells, where FGF21 protein levels were undetectable. n = 8, 2 wells from 4 independent experiments evaluated in parallel. The data is presented as mean +/- SEM. **p<0.01, determined by two-way ANOVA analysis with Dunnett correction. Figure 3b is created in BioRender. Møller, P. (2025) https://BioRender.com/o87c709 .

Article Snippet: FGF21 was measured on fasting serum samples by the human FGF21 Quantikine ® ELISA assay essentially as described (R&D Systems, Abingdon, UK).

Techniques: Concentration Assay