The research, published in the BMJ Open Diabetes Research & Care Journal, tested the relationship between estrogen and glucose absorption in vivo and in vitro. The glucose absorption was measured specifically in the duodenum.

For the human study, the glucose absorption in young women (20–30 years) were considered. Testing was done during the premenstrual and preovulatory phases, which constituted low and high levels of estrogen, respectively. The glucose absorption in the premenstrual period was worse compared to that in the preovulatory period.

For the mice study, female mice with ovariectomy (OVX) were considered to mimic estrogen deficiency. Compared to the control group (non-OVX), the OVX group reported poor glucose absorption, higher abdominal weight, reduced expression of estrogen receptors (ERα, ERβ) in the intestine, and inulin resistance.
For the third study, a human-derived SCBN cell line was used. The cell line was treated with 17β-estradiol.

The genes for ERα or ERβ (estrogen receptor) were also knocked out. Following this, the glucose transporters SGLT1 and GLUT2 were measured. It was found that estradiol upregulated the expression of SGLT1 and GLUT2 receptors. ERα receptor was found to be crucial in glucose absorption, while ERβ had little impact.
This study highlights the positive correlation between estrogen levels/genes and glucose absorption in various models.