Isolation of three chromatophorotropic hormones from the eyestalk of the shrimp Crangon crangon

The hormones present in the water extract of the eyestalks of Crangon crangon (L.) were separated by gel filtration on Sephadex G-25 fine in 0.1 M acetic acid. Chromatophorotropic activity was present in 3 separate fractions. Peak II (Fig. 1) contained Black Pigment Dispersing Hormone (BPDH); a concentrating activity, especially towards the pigment of leucophores, was present in fraction IIIA (WPCH). Peak IV contained Red Pigment Concentrating Hormone (RPCH). Combining BPDH with RPCH in the ratio 5:1, effects of lightening of the body and darkening of the telson and uropods were observed. A similar effect was produced when BPDH and WPCH were combined in the ratio 1:1. Such effects have not been previously described for eyestalk hormones, but only for the hormones of the tritocerebral commissure. In the crude water extract of the eyestalk, BPDH is inhibited by the remaining 2 hormones (WPCH and RPCH), and shows no dispersing effect when tested on eyestalkless C. crangon.