Annual and Proecdysial Variations in Urine Production in Crayfish!

THE CRUSTACEAN X organ-sinus gland complex has been extensively studied and shown to regulate such diverse activities as molting, integumentary and retinal pigment movements, blood glucose levels, ovarian development, and many others. The elucidation of the controlling mechanisms of these activities is complicated by the interdependent relationships among them. Further complications arise from the fact that in crustaceans, as in most organisms, seasonal and life cycles may be superimposed upon daily cycles and changes. The neuroendocrine control of water metabolism has been studied previously in relation to proecdysial uptake of water. Scudamore (1947) observed that increased water content in the tissues was responsible for the abnormal weight increases in crayfish induced to molt by eyestalk extirpation. Sinus gland implants partially prevented this increased water content, suggesting that factors from the X organ-sinus gland complex are responsible for maintaining proecdysial water metabolism in animals with intact eyestalks. Rapid responses to osmotic stress are necessary for homiostatic salt and water balance. Riegel (1960) reported that the handling of crayfish resulted in a spontaneous hyperglycemia, prolonged cessation or marked decrease in urine production, and sometimes glycosuria. Such an effect on urine production may suggest neural and/or hormonal control. Further evidence for a fast-acting principle for salt and water balance in the crayfish was suggested by Kamemoto et al. (1966). Our previous studies on the crayfish Procambarus clarkii (Kamemoto et aI., 1966; Kamemoto and Ono, 1967, 1968b) have suggested that neuroendocrine factors from the brain and