Current research interests and activity in the laboratory concentrate on:

A. The endocrine control of hydromineral balance
B. The endocrine control of appetite and energy homeostasis.

Our experimental approach integrates several techniques. These include whole animal physiology and behavior studies, primary cell culture models for ion transporting epithelia, molecular biology tools as well as a variety of other methodologies. The research is driven by imperatives that include environmental considerations, evolutionary significance and animal health issues (stress reduction).

A. Endocrine control of hydromineral balance: To maintain hydromineral balance, fish residing in freshwater combat ion loss and volume loading through the tissue- and cell-specific actions of ionoregulatory hormones. The endocrine mechanisms of action that limit diffusive ion loss (e.g. across the gills) and promote active ion acquisition are still not fully understood. By manipulating hydromineral status and by using a novel suite of experimental techniques (e.g. reconstructed in vitro gill models) we are gaining new insight into the endocrine control of ionoregulatory homeostasis in teleost fish. Of particular interest are similarities found between the endocrine control of permeability in lower vertebrate and higher vertebrate epithelia.

B. Endocrine control of appetite and energy balance: In mammals, hypothalamic regions responsive to peripheral endocrine information (e.g. insulin, leptin, gut hormones) exert coordinated regulation of food intake and metabolism. The mammalian hypothalamus evidently possesses at least two major groups of neurons that integrate peripheral information into either orexigenic (neuropeptide Y [NPY]; agouti-related protein [AgRP]) or anorexogenic signals (a-melanocyte-stimulating hormone [a-MSH]; cocaine and amphetamine-related transcript [CART]) that respectively stimulate and inhibit appetite. Although in teleosts many of these neuropeptides (or their homologues) possess similar properties, central regulation of energy balance is poorly understood, as are environmental contributions. It is the relationship between energy balance/appetite and environmental conditions that is emphasized in this research. A novel example is the recently described prolactin releasing peptide (PrRP) which has been found to suppress appetite and release prolactin (an important ionoregulatory hormone in fish).