The intramuscular electroporated injection of a protease-resistant growth hormone-releasing hormone ("GHRH") cDNA into rat dams at 16 days of gestation resulted in the enhanced long-term growth of the F1 offspring. The offspring were significantly heavier by one week of age and the difference was sustained to 10 weeks of age. Consistent with their augmented growth, plasma IGF-I concentration of the F1 progeny was increased significantly. The pituitary gland of the offspring was significantly heavier, and contained an increased number of somatotropes (cells producing GH) and lactotrophs (prolactin-secreting cells), and is indicative of an alteration in cell lineages. These unique findings demonstrate that enhanced GHRH expression in pregnant dams can result in intergenerational growth promotion, by altering development of the pituitary gland in the offspring.