Changes in the concentration of intracellular calcium ions regulate an enormous variety of physiological functions in nearly all cells. These functions include hormone and neurotransmitter secretion, skeletal muscle contraction, heart rate and force of contraction, digestive and excretion processes, and control of DNA expression and protein synthesis. Changes in intracellular calcium levels are also involved in more global physiological and pathological events, which include learning and memory, cell and organ development, neurological and degenerative disorders and aging, to name a few. Dr. Korn is interested in determining the physiological circumstances and the different parts of the cells that are involved in elevation and reduction of intracellular calcium levels during hormone secretion. By using a technically sophisticated approach of combining patch clamp electrophysiology, video imaging and photometry, he will explore the mechanisms by which calcium regulates growth hormone secretion from somatotrophs. Somatotrophs an anterior pituitary cell type, is an excellent system to use since growth hormone secretion is under the excitatory hormonal control of growth hormone releasing factor and inhibitory hormonal control of somatostatin. Dr. Korn will analyze the time course of calcium changes in different cytoplasmic compartments following the stimulation and inhibition of hormone secretion. The results are likely to give answers with widely ranging implications for understanding cellular processes as well as to provide new insights specifically into the mechanisms governing growth hormone release and the control of ion channels in endocrine cells. Since the results will have implications for how hormone secretion can be manipulated in both man and animals, the findings may eventually be important for the field of animal husbandry, for associated agricultural industries, and the pharmaceutical industry.
