STX affords neuroprotection in short-term OVX, middle-aged rats when administered after ischemia.

<p>Middle-aged female rats were subjected to sham surgery or global ischemia (Isch) 1 week after OVX. Panel A shows representative photomicrographs of hippocampal neurons in the dorsal CA1 region 7 days after sham surgery or global ischemia in animals injected ICV immediately after reperfusion with either vehicle (DMSO) or STX (50 µg). Scale bars: low magnification, 400 µm; higher magnification, 60 µm. Panel B: Quantification of living pyramidal neurons was performed in the CA1 region of the hippocampus 7 days after ischemia. Neurons were counted in 3 sectors (lateral, middle and medial) of the dorsal hippocampus. ANOVA followed by Newman Keuls, * p<0.001 versus sham, ** p<0.001 versus ischemia/vehicle.</p

Chemical structure of the natural estrogen 17β-estradiol and non-classical estrogen receptor agonists.

<p>G1: GPR30 agonist; STX: diphenylacrylamide compound (SERM) that does not bind ER-α or ER-β.</p

STX does not alter insulin content or blood glucose homeostasis at long-term in male mice.

<p>A, Body weight in male mice before and after the 6 day-treatment with either vehicle or STX; n = 5 mice/condition. B, Fasting glycemia in the following morning after the 6-day treatment with vehicle or STX treated mice (n = 5 mice/condition). C, IPGTT in the same mice as in B; vehicle (•), STX (○); n = 4–5 mice/condition. D, Insulin content in isolated islets from vehicle and STX-treated mice; n = 60–120 islets from 2–3 mice/condition.</p

STX does not change glucose homeostasis in ovariectomized female mice.

<p>A, Intraperitoneal glucose tolerance test (IPGTT) in ovariectomized female mice after one single dose of vehicle (•) or 100 µg/kg STX (○). B, Area under the curve in the IPGTT in A; n = 7–8 mice/condition. C, Body weight in ovariectomized female mice before and after the 6 day-treatment with either vehicle or STX; n = 5–6 mice/condition. D, Fasting glycemia in the following morning after the 6-day treatment with vehicle or STX treated mice (n = 5–6 mice/condition). E, IPGTT in the same mice as in D; vehicle (•), STX (○); n = 5–6 mice/condition. F, Insulin content in isolated islets from vehicle and STX-treated ovariectomized female mice; n = 110–140 islets from 4–6 mice/condition.</p

STX increases glucose-induced plasma insulin levels.

<p>A, Plasma insulin concentration (µg/l) measured at 30 min after a 2 g/kg glucose load in male mice treated with vehicle or 100 µg/kg STX; n≥7 mice/condition. B, Insulin tolerance test (ITT) in male mice after treatment with vehicle or 100 µg/kg STX; n = 11 mice/condition. C, Plasma insulin concentration (µg/l) measured at 30 min after a 2 g/kg glucose load in female mice treated with vehicle or 100 µg/kg STX; n = 5–6 mice/condition. D, Insulin tolerance test (ITT) in female mice after treatment with vehicle or 100 µg/kg STX; n = 7–8 mice/condition. * p<0.05, ** p<0.01.</p

The GPR30 agonist G1 mimics short latency E2 potentiation of hippocampal CA1 neuronal excitability.

<p>Changes in field EPSPs in response to E2 or G1 were measured on hippocampal slices prepared from OVX young adult female rats. Schaffer collaterals were activated by monopolar stimulation. Slices were perfused with Ringer's solution until a stable baseline response was obtained. They were then perfused for 15 min with Ringer's solution containing the vehicle and then with 10 nM E2 (A) or G1 (B). Bins of 1 min were plotted. It was frequently possible to record synaptic activity from more than one slice from the same animal in a recording session. Therefore, to test G1, we recorded from 14 slices originating from 9 different OVX females; of these, 9 exhibited an increase in the fEPSP. Similarly, 8 out of 9 slices from 6 different animals responded to E2. Only responding slices are illustrated in the figures.</p

G1 and E2 afford similar levels of neuroprotection when administered to young rats immediately after ischemia.

<p>Panel A shows representative photomicrographs of hippocampal neurons in the dorsal CA1 region 7 days after sham surgery or global ischemia (Isch) in young adult female rats that were OVX for 1 week and injected ICV with either E2 (2.25 µg), G1 (50 µg) or vehicle (DMSO) immediately after ischemia. Scale bars: low magnification, 400 µm; higher magnification, 60 µm. Panel B: Quantification of living pyramidal neurons was performed in the CA1 region of the hippocampus 7 days after ischemia. Neurons were counted in 3 sectors (lateral, middle and medial) of the dorsal hippocampus. ANOVA followed by Newman Keuls, * p<0.001 versus sham, ** p<0.001 versus ischemia/vehicle.</p

STX enhances calcium entry in islets and isolated β-cells.

<p>A, [Ca²⁺]_i recording of an islet of Langerhans in the presence of 8 mM glucose; 10 nM STX was added to the perfusion when indicated; n = 11 islets from 3 different male mice. B, [Ca²⁺]_i recording of an isolated pancreatic β-cell in the presence of 8 mM glucose; 10 nM STX was added to the perfusion when indicated. C, Area under the curve in [Ca²⁺]_i recordings from isolated β-cells. * p<0.000005; n = 100 cells from 3 different male mice.</p

STX enhances glucose-induced insulin secretion in islets from male mice following a dose-response curve.

<p>A, Measurement of insulin secretion in isolated islets from male mice at different STX concentrations in the presence of 8 mM glucose. The insulin secretion in response to 16 mM glucose was used as an internal control. Insulin secretion experiments were performed for 1 hour, in groups of 5 islets. At least 75 islets were used per condition, from 12 different mice. B, The same as in A, but with islets from female mice. At least 110 islets were used per condition in groups of 5, from 15 different mice. C, Insulin secretion in response to 8 mM glucose in the absence or presence of 10 nM STX, 1 µM or 10 µM ICI 182,780 as indicated. Between 20 and 80 islets were used per condition in groups of 5, from 9 different mice. * p<0.05 <i>vs.</i> 8 mM glucose; # p<10⁻⁴<i>vs.</i> 3 mM glucose; +p<0.05 <i>vs.</i> STX alone.</p

STX improves glucose sensitivity in male mice.

<p>A, Intraperitoneal glucose tolerance test (IPGTT) in male mice after injection of Vehicle (•) or 100 µg/kg STX (○). B, Area under the curve in the IPGTT in males; n = 6–7 mice/condition. C, IPGTT in female mice. D, Area under the curve in the IPGTT in females; n = 7 mice/condition. * p<0.05, ** p<0.01.</p