The effect of acclimation temperature on proliferation of erythropoietic precursors in Carassius auratus and on the uptake of tritiated thymidine in haematopoietic and intestinal tissue

The authors studied the cellular proliferation of undifferentiated erythropoietic precursors in the goldfish Carassius auratus acclimated at various temperatures: 5, 10, 20, 30 and 350C. The combined use of high-resolution autoradiography and DNA labelling with 3H-TdR made it possible to study the duration of the cellular cycle from the decrease in the number of grains/nucleus with time. A shortening of the mitotic cycle was found for high acclimation temperatures, together with an increase in the labelled cell fraction and in the number of grains/nucleus in the four erythropoietic cellular precursors. The authors also studied the uptake of 3H-TdR in intestinal and haematopoietic tissue, observing increased uptake in the haematopoietic tissue with temperature over the range considered, and a decrease in uptake by the intestine between 25 and 350C. The number of cells per gram of fish decreases at high acclimation temperatures