Hypoglycemia identified by a continuous glucose monitoring system in a second-trimester pregnant woman with insulinoma: a case report

BACKGROUND

Insulinoma associated with pregnancy is a very rare condition and can be difficult to diagnose. Here, we present an interesting case of insulinoma occurring during pregnancy with special attention paid to the use of a continuous glucose monitoring system to detect hypoglycemia.

CASE PRESENTATION

A 36-year-old white woman in the second trimester of pregnancy presented with recurrent episodes of hypoglycemia associated with neuroglycopenic symptoms. The use of a continuous glucose monitoring system confirmed hypoglycemia. Serum insulin, C-peptide, and proinsulin values confirmed endogenous hyperinsulinism. A tumor mass was localized at the tail of her pancreas by endoscopic ultrasound and confirmed by magnetic resonance imaging. Surgery performed at 21 weeks of gestation by distal pancreatectomy confirmed the presence of a 15 mm diameter endocrine tumor at the tail of her pancreas and led to a cure.

CONCLUSIONS

Hypoglycemia during pregnancy could be due to insulinoma. Use of a continuous glucose monitoring system could help to detect hypoglycemia in these patients.

Adiponectin/leptin ratio and insulin resistance in pregnancy

Objective

Pregnancy is characterized by progressive insulin resistance. The present study evaluated whether the adiponectin/leptin ratio is associated with insulin resistance in pregnancy, since this ratio has been shown to be associated with insulin resistance in obesity, type 2 diabetes mellitus, metabolic syndrome and polycystic ovary syndrome.

Methods

In this cross-sectional study, adiponectin and leptin concentrations were measured in pregnant women using enzyme-linked immunosorbent assays. Insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA–IR).

Results

Mean ± SD age of the participants ( n = 74) was 30.76 ± 4.27 years, mean ± SD gestational age was 26.81 ± 3.52 weeks and median body mass index (BMI) before pregnancy was 22.68 kg/m2 (interquartile range 20.75–26.79 kg/m2). There was a significant correlation between the HOMA–IR and leptin concentration, but not between the HOMA–IR and adiponectin concentration. There was a significant inverse correlation between the HOMA–IR and adiponectin/leptin ratio. The adiponectin/leptin ratio was inversely correlated with BMI before pregnancy.

Conclusion

The adiponection/leptin ratio inversely correlates with HOMA–IR in pregnancy.

Adipocytokines and insulin resistance across various degrees of glucose tolerance in pregnancy

OBJECTIVE

Gestational diabetes mellitus is characterized by progressive insulin resistance. Adipocytokines are thought to be associated with insulin resistance. This cross-sectional study evaluated the associations between serum concentrations of several adipocytokines and insulin resistance at different stages of glucose tolerance in pregnancy, using the homeostasis model assessment of insulin resistance (HOMA-IR) as a reference.

METHODS

According to oral glucose tolerance test results, 74 pregnant women were divided into three groups: normal glucose tolerance (n = 25); intermediate glucose tolerance (n = 19); gestational diabetes mellitus (n = 30). Adiponectin, leptin, resistin, visfatin and retinol-binding protein 4 (RBP4) concentrations were measured using enzyme-linked immuno sorbent assays.

RESULTS

Groups were comparable regarding age, week of gestation and body mass index before gestation. There were statistically significant between-group differences in HOMA-IR, but no significant differences regarding serum adipocytokine concentrations.

CONCLUSIONS

Adipo nectin, leptin, resistin, visfatin and RBP4 were not associated with the degree of glucose tolerance in pregnancy. Concentrations of these adipocytokines are not sufficiently sensitive to replace HOMA- IR in pregnancy.

Comparison of alterations in insulin signalling pathway in adipocytes from Type II diabetic pregnant women and women with gestational diabetes mellitus

AIMS/HYPOTHESIS

The cellular mechanisms for the insulin resistance in pregnancy and gestational diabetes mellitus are not known. The membrane protein plasma cell glycoprotein PC-1 has been identified as an inhibitor of insulin receptor tyrosine kinase activity and could have a role in insulin resistance. This study aimed to examine the effects of insulin on glucose transport and changes in insulin receptor tyrosine phosphorylation, IRS-1 and PC-1.

METHODS

Adipocytes were obtained either during elective cesarean section from three groups of subjects (Type II diabetic pregnant women ( n=6) women with gestational diabetes mellitus ( n=10) and pregnant women with normal glucose tolerance ( n=6) as pregnant control subjects) or during elective gynaecological surgery from non-pregnant ( n=6) control subjects.

RESULTS

Insulin stimulated glucose transport was reduced by 50% in women with gestational diabetes mellitus and 70% in pregnant women with Type II diabetes, compared to the non-pregnant control subjects. After maximal insulin stimulation of adipocytes, IRTK phosphorylation was reduced by 29.5% in women with gestational diabetes mellitus and 44.5% in women with Type II diabetes, compared to the non-pregnant control subjects. We also found that IRS-1 phosphorylation was reduced by 32% and 48%, respectively. On the other hand, PC-1 content in adipocytes in women with gestational diabetes mellitus increased by 320% and 668% in Type II diabetic women, compared to the non-pregnant control subjects.

CONCLUSIONS/INTERPRETATION

Our results indicate that women with gestational diabetes mellitus and Type II diabetes have increased PC-1 content and suggest that this could contribute to lower phosphorylation levels of IRTK and IRS-1. Furthermore, these postreceptor defects in insulin signalling pathway are greater in both groups compared to the women with normal pregnancy. However, results from women with Type II diabetes show that pre-existing insulin resistance lead to an even greater deterioration of the signalling pathway.