An In vitro effect of insulin on glycogen levels in the common liver fluke, fasciola hepatica (Linnaeus, 1758)

Energy metabolism and its regulation in the adult liver flukeFasciola hepatica

“…Glycogen levels constitute up to 4 % of the wet weight of the adult (Hines, 1969;Lloyd & Barrett, 1983a), and it is stored mainly in the parenchymal cells. Starvation results in the mobilization of glycogen, whereas re-feeding results in the re-synthesis of depleted stores (von Brand & Mercado, 1961).…”

Effects of thyroxine and insulin on the trematode Schistosomatium douthitti

“…In vitro insulin (200 units/30ml) Ex-sheep enhanced glycogen deple tion of whole worms when oral suckers were tied; insulin was thought to be taken up via the tegument Cattle normal fluctuation in fecal egg counts was suppressed by insulin administration; degree of suppression is depend ent upon the dose of insulin Hines, 1969Dorsman, 1967 cysticerci of Taenia crassiceps…”

“…No published reports relating to effects of the latter hormone on parasites have appeared, but the known effects of insulin on helminths, summarized in Table 9, indicate lack of unanimity. For example, insulin is said to 1) stimulate glycogenolysis (Pantelouris, 1964;Hines, 1969), 2) stimulate glycogenesis (Sekardi, 1965) Additionally, some authors used worm fragments while others used whole…”

Effects of thyroxine and insulin on the trematode Schistosomatium douthitti

“…No published reports relating to effects of the latter hormone on parasites have appeared, but the known effects of insulin on helminths, summarized in Table 9, indicate lack of unanimity. For example, insulin is said to 1) stimulate glycogenolysis (Pantelouris, 1964;Hines, 1969), 2) stimulate glycogenesis (Sekardi, 1965), and 3) have no effect on the carbohydrate metabolism (Isserhoff and Read, 1968) of Fasciola hepatica.…”

“…It has been also suggested that insulin enters by way of the tegument (Hines, 1969 It is interesting to note, in the light of the previously described production of hormone-like substances by larval platyhelminths, that in the most successful study to date, effects of insulin were demonstrated on a larval (cysticercus) cestode (Esch, 1969). However, it is unduly speculative to suggest that any relationship exists between the produc tion of hormone-like substances and the ability of larval forms to respond to exogenous insulin.…”