Involvement of Eyestalk Factors in the Neuroendocrine Control of Osmoregulation in Adult American Lobster Homarus americanus

Osmoregulatory capacity (OC) decreased by ∼50% after eyestalk ablation in adult Homarus americanus when in dilute media. OC was used to assay sinus gland extracts. Injection of total extracts and of some HPLC-separated fractions of sinus glands into destalked lobsters increased OC. One of the described crustacean hyperglycemic hormone isoforms influences osmoregulation. Another fraction of the sinus gland extracts modifies osmoregulation but its nature remains unknown. Variations in OC were examined in response to ecdysterone, Phe-Met-Arg-Phe-NH2, and atrial natriuretic factor but effects were minimal.