Gloria E. Hoffman, Ph.D.
Laboratory of Neuroendocrine Cell Interaction
The research in Dr. Hoffman’s laboratory uses brain systems regulating endocrine and autonomic function as model systems for studying the processing of excitatory stimuli and consequent stimulus-transcription coupling. One of the principal systems the laboratory uses is the neurons containing luteinizing hormone releasing hormone (LHRH or gonadotropin releasing hormone, GnRH), a polypeptide produced in the CNS which regulates secretion of gonadotropins from the anterior pituitary. These neurons are an essential component of reproductive function and marked increases in their activity accompany the preovulatory LH surge. Their study has been particularly challenging since they are diffusely organized within the forebrain, small in size, and few in number, making conventional approaches for studying their activity impractical. Recently, molecular biologists determined that certain immediate early genes could be expressed in neurons after stimulation. Dr. Hoffman’s laboratory then determined that the immediate early genes, c-fos, and c-jun are expressed in LHRH neurons during an LH surge. The appearance of immediately early gene proteins accurately reflects LHRH stimulated activity. Using this approach, this laboratory has examined the dynamics of LHRH activation, participation of steroid hormones in this process, and the role of selected afferents containing catecholamines, neuropeptides and excitatory amino acids in regulating LHRH activity. Recently attention has shifted from where immediate early gene proteins are expressed to what changes in gene expression within LHRH neurons (and their afferents) are triggered by or accompany immediate early gene expression. Approaches using double label in situ hybridization have been most useful in this regard. In addition, similar strategies are used to study the functional activation of vasopressin, oxytocin and CRF systems triggered by a variety of stimuli.
Recent Publications:Hoffman GE, Le WW, Abbud R, Lee WS, Smith MS 1994 Use of Fos-related antigens (FRAs) as markers of neuronal activity: FRA changes in dopamine neurons during proestrus, pregnancy and lactation. Brain Research 654:207-215.
Berghorn KA, Bonnett JH, Hoffman GE 1994 cFos immunoreactivity is enhanced with biotin amplification. Journal of Histochemistry and Cytochemistry 42:1635-1642.
Wang HJ, Hoffman GE, Smith MS 1995 Increased GnRH mRNA in the GnRH neurons expressing cFos during the proestrous LH surge. Endocrinology 136:3673-3676.
Hoffman GE, Dohanics J, Watson RE Jr, Wiegand SJ 1996 The sexually dimorphic projection to the preoptic area arises in the ventromedial nucleous of the hypothalamus. Molecular Brain Research 36:201-210.
