Targeting transforming growth factor α expression to discrete loci of the neuroendocrine brain induces female sexual precocity

Abstract

Precocious puberty of cerebral origin is a poorly understood disorder of human sexual development, brought about by the premature activation of those neurons that produce luteinizing hormone-releasing hormone (LHRH), the neuropeptide controlling sexual maturation. An increased production of transforming growth factor alpha (TGF alpha) in the hypothalamus has been implicated in the mechanism underlying both normal and precocious puberty. We have now used two gene delivery systems to target TGF alpha overexpression near LHRH neurons in immature female rats. Fibroblasts infected with a retroviral construct in which expression of the human TGF alpha gene is constitutively driven by the phosphoglycerate kinase promoter, or transfected with a plasmid in which TGF alpha expression is controlled by an inducible metallothionein promoter, were transplanted into several regions of the hypothalamus. When the cells were in contact with LHRH nerve terminals or in the vicinity of LHRH perikarya, sexual maturation was accelerated. These results suggest that precocious puberty of cerebral origin may result from a focal disorder of TGF alpha production within the confines of the LHRH neuron microenvironment.