Sj. Potocnik et Em. Wintour, DEVELOPMENT OF THE SPLEEN AS A RED-BLOOD-CELL RESERVOIR IN LAMBS, Reproduction, fertility and development, 8(3), 1996, pp. 311-315
In adult sheep and other animals the spleen is a reservoir of red bloo
d cells (RBCs), which can be mobilized by adrenaline-induced splenic c
ontraction. Adrenaline does not increase the haematocrit in the ovine
fetus. This study examined the development of a releasable store of RB
Cs in the spleen of lambs during the neonatal period. Spleen and body
weights were measured in 126 fetuses and lambs, ranging in age from 60
days' gestation to 94 days post partum. Spleen weight, as a percentag
e of body weight, stabilized at 0.56 +/- 0.02%, 20 days post partum. A
drenaline infusion (5 mg kg(-1) min(-1)) was associated with a mean in
crease in arterial haematocrit (Hct) of 7.6 and 5.8 Hct % in lambs at
20-24 and 50-52 days of age respectively (n=4 at each age). The spleen
in lambs has become a significant reservoir of RBCs by 20-24 days of
age and may contain reserves equivalent to those in adult sheep. This
splenic reserve is developed before the post-natal drop in haematocrit
occurs.