Oral contraception enhances growth hormone responsiveness to hyper- and hypoglycaemia

Aims Plasma glucose levels influence growth hormone concentrations. Oral contraceptives are known to affect circulating growth hormone levels and glucose metabolism. While growth hormone plays an important role in hypoglycaemia counter-regulation, it has been shown that oral contraceptives increase growth hormone concentrations. In this context, we tested if serum growth hormone concentrations display a differential response on glycaemic variations in healthy women using oral contraceptives and those not using contraceptives. Methods Fifteen healthy women with oral contraceptive treatment and 10 without participated in a stepwise hyper- and hypoglycaemic glucose clamp procedure. Serum growth hormone concentrations were measured at euglycaemic baseline and subsequently at plasma glucose plateaus of 8.8, 6.8, 4.8 and 2.8mmol/l. Results Growth hormone values were significantly higher in women using oral contraceptives throughout the experiments (P=0.001). Hyperglycaemia decreased growth hormone concentrations in women using oral contraceptives (P=0.009), but not in those who were not using oral contraceptives (P=0.241). Hypoglycaemia significantly elevated growth hormone concentrations in women using oral contraceptives (P=0.009), but not in those not using oral contraceptives (P=0.094). Maximum growth hormone values were reached at the end of the hypoglycaemic plateau, with significantly higher concentrations in the group using oral contraceptives than in the group not using oral contraceptives (P=0.016). Conclusion Healthy women on oral contraceptive treatment display an increased responsiveness of growth hormone to hypoglycaemic, as well as hyperglycaemic conditions and generally higher serum growth hormone concentrations than women without oral contraceptives. Given the known boosting effects of growth hormone on hypoglycaemic hormonal counter-regulation, oral contraceptives may thus be a pharmacological candidate contributing to combat hypoglycaemia unawareness in women with diabetes in the future.