Hepatic and peripheral responsiveness to a glucose infusion in pregnancy

To enhance glucose transfer to the fetus, the pregnant woman may evidence hyperglycemia after feeding. In order to evaluate whether hepatic responsiveness, in contrast to peripheral uptake, contributes to this response, the glucose production rate was measured in 15 pregnant nondiabetic patients, in 12 pregnant insulin-dependent diabetic patients, and in 12 nonpregnant nondiabetic patients (controls). Seventeen of the women were infused with 3.2 mg X kg-1 min-1 of glucose. All glucose-infused groups had an elevated plasma glucose concentration compared to their saline solution-infused counterparts. The glucose production rate was suppressed in the nondiabetic glucose-infused groups. The glucose production rate of the pregnant nondiabetic patients was similar to that of the pregnant insulin-dependent diabetic patients, but the glucose production rate of the latter group was more variable than that of nonpregnant nondiabetic controls (p less than 0.05). We conclude that in third trimester, pregnant nondiabetic and insulin-dependent diabetic subjects have parallel hepatic and peripheral responsiveness to glucose and insulin compared to their nonpregnant counterparts. Although the pregnant patient may exhibit relative insulin insensitivity, hepatic or peripheral responsiveness to insulin would not explain the persistence of the relative hyperglycemia noted clinically.