GEORGE DELAHUNTY

Research Interests: Molecular Biology of Insulin-Like Growth Factors

Serotonergic Control of Cardiovascular Function

Research in Progress:

The first project attempts to understand the molecular endocrinology of growth by studying the evolution and tissue specific expression of the insulin-like growth factor I (IGF-I). Currently, research projects are focused on the tissue specific expression and growth hormone control of the IGF-I genes in Xenopus laevis, an amphibian model commonly employed to study development. Recombinant DNA techniques are used to generate cDNA clones, which code for the IGF-I hormone in Xenopus. The cDNA clones are also used as probes to determine the expression of the IGF-I gene during development. Studies of IGF-I expression are specifically concerned with hormonal control of gene expression by growth hormone in the adult animal. In addition, a PCR strategy using Xenopus genomic DNA as template is being employed to characterize the intron – exon structure of the IGF-I genes. A Xenopus genomic DNA library is currently being screened to characterize the genomic DNA and identify the promoter region for gene expression.

The second project studies the effect of serotonin on cardiovascular function using the bullfrog as a model system. Students have utilized both in vivo and in vitro preparations to examine the effect of serotonin on cardiac function and blood pressure regulation. Currently studies are being carried out to characterize the serotonergic receptor subtype(s) involved in the cardiovascular response.

Representative Student Independent Research Projects:

Sleeper, Aimee The effects of serotonin on the heart rate of Rana catesabiana.

Bixler, Heather Tissue-specific expression of insulin-like growth factor I in Xenopus laevis.

Hoffeld, Erika Tissue-specific expression and growth hormone regulation of IGF-I’ and IGF-I” in adult Xenopus laevis liver.

Czaya, Catherine Growth Hormone regulation of tissue specific expression of IGF-I transcripts in Xenopus laevis.