EVIDENCE FOR HORMONE-CONTAINING GRANULES IN SINUS GLANDS OF THE FIDDLER CRAB UCA PUGILATOR

¹ Biological Laboratories, Harvard University, Cambridge 38, Mass.

1. Homogenates of sinus glands in isotonic sucrose cause little dispersion of black chromatophores when injected into legs or whole Uca. A liberation of hormone occurs when homogenates of sinus glands in isotonic sucrose are diluted in distilled water. A fraction, sedimentable by high speed centrifugation, when resuspended in distilled water and injected into the test animals, induces a dispersion of the chromatophores. These results support the view that the black chromatophore-dispersing hormone is contained within granules in sinus glands.

2. The release of the hormone from the granules, obtainable by lowering the tonicity of the medium or by dilution in isotonic saline solutions, suggests that the granules possess a semipermeable membrane.

3. The release of the hormone from the granules is increased by heating, by freezing and thawing, and by the action of detergents and digitonin.

4. The black chromatophore-dispersing hormone may be a polypeptide, since it is inactivated by extracts of hepatopancreas and by chymotrypsin.

5. The rate of disappearance of the hormone from the blood of the crab is very slow.