. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRUSTACEAN RETINAL PIGMENT HORMONE 327 Libinia extracts having a concentration of eyestalks per nil. After retinal pigment hormone has been isolated in pure form, dosage-response relations of what- ever species were being used could be compared with the homogeneous preparation as a reference. The stability and solubility properties described above show that eyestalks retain retinal pigment hormone activity after being oven-dried or lyophilized. This, and Carlson's (1936) report of chromatophorotropic activity in eye
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CRUSTACEAN RETINAL PIGMENT HORMONE 327 Libinia extracts having a concentration of eyestalks per nil. After retinal pigment hormone has been isolated in pure form, dosage-response relations of what- ever species were being used could be compared with the homogeneous preparation as a reference. The stability and solubility properties described above show that eyestalks retain retinal pigment hormone activity after being oven-dried or lyophilized. This, and Carlson's (1936) report of chromatophorotropic activity in eyestalks dried and stored over a long period, have been useful in collecting and preparing quantities of eyestalk material for purification. We initially observed some loss in activity, accompanied by the formation of a precipitate, in fractionated eyestalk extracts thawed after storage at —20° C., and have therefore avoided repeated freezing and thawing of such preparations. The in vitro inactivation by tissue extracts and by proteolytic enzymes point out additional interesting features of retinal pigment hormone. The variety of tissue extracts which inactivate the hormone, a pH optimum of about for such inactivation, and the fact that the ability to destroy hormonal activity is thermolabile indicate a widely-occurring enzyme or group of enzymes. Whether such an enzyme system has an in vivo role in degrading hormone in the normal physiology of the retinal effectors is not known. Similar inactivation of chromatophorotropic hormone, first reported by Carstam (1951) for epidermis and later by Perez- Gonzalez (1957) and by Stephens and Green (1958) for a number of other. HOURS FIGURE 2. Rate of inactivation of distal retinal pigment hormone by enzyme in an eyestalk extract which was allowed to remain at room temperature for 12 hours. Extract was prepared from eyestalks of Please note that these images are extracted from scanned page images that may have been di
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
