Development of Digital Techniques for Analysis of Hormone Regulation of Melanophore Activity in Red Drum
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Melanophores are pigment bearing cells, which have been used as a practical method to demonstrate mechanisms of hormone interaction. A current teaching laboratory has been restructured in order to increase student participation, provide tangible results, and reduce subjectivity in procedures to more accurately analyze hormone interaction. To accomplish this, digital cameras were used to photograph scales of red drum (Sciaenops ocellatus), which were then analyzed using ImageJ software to determine melanosome area. From collected data, a region posterior to the pelvic fin and dorsal to the lateral line on the red drum was determined to yield stable basal melanophores to provide a standard starting state for student experiments. By measuring the area of basal melanophores, one can compare dispersed melanophore area after hormone treatment (α-MSH and norepinephrine) to quantify a hormone’s effect. Hormone interaction can be illustrated by subjecting scales to different hormones in series. Other chemicals such as IBMX and a K+ rich medium were also used to demonstrate melanophore regulation. Experiments showed that basal state of melanophores could not be manipulated by changing illumination of environment or by removing scales from red drum at different times of day. Physiological doses of hormones to be used in the laboratory were determined by testing various doses’ effect on melanophore activity over time. Once physiological doses were established, a sequence of serial chemical treatments was developed to best demonstrate melanophore activity by examining dispersing and aggregating effects in the presence of other chemicals. This method of melanophore analysis has proven useful as a teaching tool, but may also be used to analyze novel treatments on melanophore activity.
Russey, William Andrew (2008). Development of Digital Techniques for Analysis of Hormone Regulation of Melanophore Activity in Red Drum. Available electronically from