. Animal hormones; a comparative survey. Hormones. 90 KINETIC HORMONES—I from different spots appearing on the paper have only been tested upon eyestalkless prawns kept on a white background; in these the red chromatophores are fully dispersed owing to the lack of PLH, reinforced by the dispersing effect of direct light. It follows that only light-adapting substances causing concentration of red pig- ment can be satisfactorily identified, though by using sufficiently concentrated extracts relatively rapid reactions can be obtained (Fig. 3-16). Other parts of the nervous system yield extracts w
. Animal hormones; a comparative survey. Hormones. 90 KINETIC HORMONES—I from different spots appearing on the paper have only been tested upon eyestalkless prawns kept on a white background; in these the red chromatophores are fully dispersed owing to the lack of PLH, reinforced by the dispersing effect of direct light. It follows that only light-adapting substances causing concentration of red pig- ment can be satisfactorily identified, though by using sufficiently concentrated extracts relatively rapid reactions can be obtained (Fig. 3-16). Other parts of the nervous system yield extracts with an action similar to that of PLH, but it is more than likely that. time (min.) Fig. 3-16. Effect of extracts of the tritocerebral commissures on the dispersed red pigment in the chromatophores of eyestalkless prawns, Penaeus hraziliensis. The effect of sinus gland extracts would be similar. The abscissae represent time in minutes after the injections; the ordinates, the state of dispersion of the pigment on the same scale as the melanophore index. The dotted lines show that readings taken at night are closely similar to those by day, shown in full lines. The extracts from the post-commissure region ) are rather more active than those from the main commissure (c.) in yielding a pigment-concentrating hormone, the effect of which is to cause rapid pigment concentration. This wears off as the hormone is destroyed in the tissues and the pigment returns to its original state of dispersion (from Knowles, 1953).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Jenkin, Penelope M. Oxford, New York, Pergamon Press
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjecthormones
