CARBOHYDRATE METABOLISM IN THE MENSTRUAL CYCLE

Abstract

Blood sugar, serum insulin and growth hormone levels in response to 100 g. of oral glucose were studied under carefully controlled conditions on days 9, 18 and 27 of the menstrual cycle in 20 healthy women aged 18 to 20 years. The results indicate that blood sugar and serum insulin levels in response to oral glucose loading do not alter significantly in the menstrual cycle. Seven of the women had repeat studies on the same days three cycles later. No significant change in blood sugar or serum insulin levels occurred between cycles. The fasting growth hormone level was highest at the time of impending menstruation in 11 subjects (55 per cent) but the difference in mean values for the group as a whole was not statistically significant. It is concluded that the changes in endogenous hormone levels in a menstrual cycle do not produce significant alterations in carbohydrate metabolism in normal women in this age group. The reported divergence of blood glucose and insulin levels after oral glucose in the menstrual cycle may reflect the interaction of other factors such as age and parity on glucose tolerance. It is suggested that investigations into the metabolic effects of oral contraceptive steroids on these parameters should be performed in nulliparous women in a similar age range.