Phosphate compounds in red cells of the chicken and duck embryo and hatchling

Acclimation to hypothermic incubation in developing chicken embryos(Gallus domesticus)

“…This suggests that in hypothermic embryos organic phosphates played little role in modifying hemoglobin-O2 affinity, and that incubation temperature and the nature of the hemoglobins present were probably the primary reasons for the significant drop in P50 observed by HH 43-44. The effect of temperature on organic phosphate concentration in the chicken embryo has never been examined but, in general, [ATP] and [2, from these experiments are similar to those of numerous other studies on chicken embryos (Isaacks and Harkness, 1975;Isaacks et al, 1976;Bartlett and Borgese, 1976;Baumann and Meuer, 1992) and other precocial embryos including turkeys, pheasants, guinea fowl and ducks (Isaacks et al, 1976;Bartlett and Borgese, 1976).…”

“…In addition to being altered by changes in embryo acid-base status, temperature and Hb type, O2 affinity of embryonic chicken blood is, of course, also affected by organic phosphate concentrations (Baumann and Meuer, 1992). Up until approximately D12 of incubation in the chicken, ATP is the primary organic modifier of hemoglobin-O2 affinity (Misson and Freeman, 1972;Bartlett and Borgese, 1976;Baumann and Meuer, 1992;Hochachka and Somero, 2002). The increase in hemoglobin-O2 affinity between D8 and D18 of incubation corresponds to the period where metabolic rate reaches its maximum pre-pipping plateau, and hypoxia begins to develop within the egg.…”

“…The increase in hemoglobin-O2 affinity between D8 and D18 of incubation corresponds to the period where metabolic rate reaches its maximum pre-pipping plateau, and hypoxia begins to develop within the egg. At this point the aerobic production of ATP is more difficult to achieve and there is a fall in blood [ATP] (Bartlett and Borgese, 1976;Nikinmaa, 1990). As [ATP] drops, anaerobic production of 2,3-bisphosphoglycerate (2,3-BPG) increases and this organic phosphate then acts as the primary allosteric modifier of hemoglobin until after hatching, when inositol polyphosphate (IPP) becomes the adult allosteric modifier (Bartlett and Borgese, 1976;Nikinmaa, 1990).…”

NTP pattern of avian embryonic red cells: role of RNA degradation and AMP deaminase/5′-nucleotidase activity

“…A key ele-ment of this process is the oxygen pressure-dependent control of the RBC organic phosphate pattern and concentration (6,9). Erythrocytes from early and midterm chick embryos contain very high concentrations of ATP [up to ϳ15 mmol/l RBC (5,8,9)], and ATP is considered to be the dominant allosteric regulator of avian embryonic hemoglobin function during embryonic development (8,29). In addition to ATP, the RBC from midterm embryos also contain large amounts of UTP and CTP [up to 9 mmol/l RBC (23)].…”