Transient growth hormone therapy to rats with low protein-inflicted intrauterine growth restriction does not prevent elevated blood pressure in later life

Intrauterine growth restriction (IUGR) is a risk factor for the development of hypertension in later life. Insulin-like growth factor I and growth hormone (GH) have the potential to improve metabolic syndrome after IUGR in adult animals. The objective of the present study was to examine whether transient GH treatment of pups after weaning can prevent the development of arterial hypertension in adult rats.

IUGR was induced in Wistar rats by isocaloric protein restriction in pregnant dams and litter size was reduced to six male neonates after birth. Recombinant human GH was applied by daily subcutaneous injections at a dose of 3 μg/g body weight between days 24 and 60 of life. Control animals received vehicle treatment (VEH) only.

Birth weight was significantly lower in low protein (LP) animals than in normal protein (NP) animals (5.1 ± 0.3 g vs. 5.9 ± 0.7 g, p < 0.05). Until weaning at day 23, LP animals reached similar body length, but had reduced body weight compared to NP animals. Intraarterially measured mean arterial blood pressure at day 120 was elevated in LP-VEH compared to NP-VEH animals (113 ± 6 mmHg vs. 101 ± 6 mmHg, p < 0.01). However, transient GH-treatment did not prevent arterial hypertension in LP animals (112 ± 5 mmHg).

Our data suggest that GH treatment between days 24 and 60 of life does not or at least not permanently reprogram blood pressure elevation after IUGR.