Programming of the Hypothalamo-pituitary-adrenal Axis and the Fetal Origins of Adult Disease Hypothesis

Unlabelled: There is now a large body of evidence to support the hypothesis that events in fetal life permanently alter the structure or function of an individual, programming later adult disease. Reduced birth weight is associated with higher blood pressure in childhood and adult life, and thinness at birth with glucose intolerance and non-insulin dependent diabetes mellitus. Programming of the hypothalamo-pituitary-adrenal (HPA) axis is an attractive hypothesis linking fetal experience and later disease, as an excess of glucocorticoids may be associated with hypertension and glucose intolerance. Moreover, animal data support this hypothesis. Exposing fetal rats to glucocorticoid reduces birth weight and leads to raised blood pressure, as well as to alterations in the HPA axis. Data on the long-term effects of exposure to glucocorticoids in human subjects are limited. Recently, however, reduced size at birth was found to be associated with higher fasting 9 a.m. plasma cortisol concentrations in adults. Raised plasma cortisol concentrations were, in turn, associated with higher blood pressure, and inversely related to measures of glucose tolerance.

Conclusion: Programming of the HPA axis by events in fetal life may be one of the mechanisms linking reduced size at birth with raised blood pressure and glucose intolerance in later life. Studies of the effects of antenatal and neonatal dexamethasone administration on later blood pressure and glucose tolerance may be warranted.