Immunocytochemical localization of hyperglycemic hormone (HGH) in the neurosecretory system of the eyestalk of the crayfish Astacus leptodactylus.

Hyperglycemic hormone (HGH) from Astacus leptodactylus can be visualized by an immunocytochemical procedure using a specific antiserum against HGH and the peroxidase-anti-peroxidase (PAP) method. HGH containing cells are localized in the most distal portion of the x-organ in the medulla terminalis. Their cell diameter is about 47 +/- 7 micrometer; the nucleus measures about 22 +/- 2 micrometer. They form a subgroup of neurosecretory cell type 1, already described for the crayfish. A large amount of this HGH material is homogeneously stored in the sinus gland. A group of fibres in the x-organ - sinus gland - tractus can be followed, due to their positive reaction with the PAP-reagent.