In vitro Uptake of Radioglucose by a Frog Lung-Fluke and Correlation with the Histochemical Identification of Glycogen

Abstract

Haematoloechus medioplexus from Rana pipiens were tested histochemically for glycogen by using the Bauer-Feulgen method. Major concentrations of glycogen occur in the oral sucker, pharynx, anterior subcuticular parenchyma, and spermatozoa. Worms maintained in vitro in glucose-saline showed no depletion of tissue glycogen after 50 hr, while worms maintained in only saline showed a partial loss of glycogen from the oral sucker, pharynx, and subcuticular parenchyma. In other experiments worms were maintained in vitro in saline containing radioglucose. After 12, 24, and 48 hr worms were sectioned and autoradiographed and compared with sections treated histochemically. The distribution of radioactivity corresponded with that of glycogen, indicating that glucose was removed from the medium and synthesized into glycogen. Grain counts were made to determine the amount of radioactivity (as C14 glycogen). The most radioactive structures were the pharynx and the anterior subcuticular musculature and parenchyma. Considerable glycogenesis also occurs in the oral sucker and deep parenchyma, but relatively little glycogen synthesis occurs in the cuticle, Mehlis'' gland, vitelline follicles, digestive ceca, and ovary. Spermatozoa synthesize glycogen only shortly after their formation. Older spermatozoa in seminal receptacles were not radioactive.