Related Experiment Videos
Pig reticulocytes. III. Glucose permeability in naturally occurring reticulocytes and red cells from newborn piglets
Insights
Newborn pigs transition from glucose-permeable fetal red blood cells to impermeable adult cells. This shift occurs through the production of new cells and the shorter lifespan of fetal cells.
Area of Science:
- Physiology
- Hematology
- Cell Biology
Background:
- Red blood cell (RBC) glucose transport changes significantly after birth.
- Fetal RBCs exhibit higher glucose permeability than adult RBCs.
Purpose of the Study:
- To investigate the developmental changes in red blood cell glucose transport in newborn pigs.
- To understand the mechanisms behind the transition from fetal to adult glucose transport characteristics.
Main Methods:
- Monitoring glucose transport in density-separated red blood cells from birth to 4 weeks of age.
- Analyzing glucose permeability rates in reticulocytes and mature red blood cells.
Main Results:
- At birth, glucose permeability increased threefold from the lightest to the densest cells.
- Reticulocytes at birth showed significant glucose permeability, which rapidly decreased within 3-4 days.
- Maturing reticulocytes lost membrane permeability to glucose, becoming nearly impermeable.
Conclusions:
- The transition to glucose-impermeable postnatal red blood cells is facilitated by the production of new, impermeable cells and the removal of older, permeable fetal cells.
- Reticulocyte maturation plays a crucial role in establishing postnatal glucose impermeability.
Abstract:
The loss of facilitated glucose transport of red cells occurring in the newborn pig was monitored in 11 density-separated cells from birth to a 4 wk of age. At birth there was a threefold increase in glucose permeability from the lightest cells to the most dense, suggesting that cells having progressively less glucose permeability are released into the circulation as gestation proceeds. Because of extraordinary stimulation of erythropoietic activity, the uppermost top fraction constituting 2-3 percent of the total cells is composed purely of reticulocytes in the growing animal. The glucose permeability of these reticulocytes which at birth has a slow but significant rate of 3.7 mumol/ml cell x min at 25 degrees C is rapidly decreased within 3-4 days to the level of reticulocytes produced in the adult in response to phenylhydrazine assault. Moreover, reticulocytes themselves discard their membrane permeability to glucose in the course of maturation to red cells. Thus, even though reticulocytes at birth are permeable to glucose, they will become red cells practically impervious to glucose within a few days. These findings suggest that the transition from a glucose- permeable fetal state to a glucose-impermeable postnatal state is brought about by two mechanisms: (a) dilution of fetal cells by glucose-impervious cells produced coincidentally with or shortly after birth; and (b) elimination of fetal cells, which have a shorter half-life, from the circulation.