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Fetal and placental growth rate in sheep has been manipulated by removal of endometrial caruncles prior to conception. This produced two groups of fetuses, one in which prenatal growth rate was similar to normal and a second group in which the fetuses were about half of the normal size. The mortality in the latter group was high, particularly after(More)
The effect of long- and short-term manipulations of uterine blood flow on fetal plasma levels of IGF-I and -II have been studied in sheep at days 125-139 of pregnancy and compared with those in near term rats and guinea pig. The primary objective is to show that both long- and short-term reduction of uterine blood flow is associated with increase in the(More)
1. Adrenaline and noradrenaline have been infused into the fetal sheep to produce plasma concentrations comparable to those seen during hypoxia. The effects have been compared with those of isoprenaline and methoxamine and the sensitivity to beta- and alpha-adrenergic antagonists has been followed. 2. Adrenaline caused an alpha-mediated increase in blood(More)
Lipid synthesis as measured by the incorporation of acetate or 3H2O into slices of foetal liver, is much higher than in slices of adult liver and shows a peak at about two-thirds of gestation. At this time the synthesis from glucose was low and reached a peak 10 days later. The changes in the activity of ATP citrate lyase, which mirrored acetate(More)
1. Foetal and maternal plasma catecholamine concentrations were measured during and after hypoxia (mean maternal Pa,02 44mmHg) in chronically catheterized sheep, 118-141 days pregnant. 2. In most foetuses the initial plasma catecholamines were smaller than 0.07 ng/ml. During hypoxia plasma adrenaline and noradrenaline always rose; there was a rise in(More)
Experimental intrauterine growth retardation was studied in sheep. Endometrial caruncles (anlagen of maternal cotyledon) were removed before pregnancy and at a second operation, catheters were implanted into the ewe and fetus at 105-135 days of pregnancy. Three groups of fetuses were defined: low birthweight-for-dates (small-caruncle), normal(More)
1. The output of corticotrophin releasing factor-like immunoreactivity (CRF) from the adrenal gland has been investigated using the 'adrenal clamp' technique in conscious calves. 2. Stimulation of the peripheral end of the splanchnic nerve for 10 min increased the mean output of CRF progressively, so that it had risen by about twentyfold, to a peak(More)
Fetal growth rate in sheep has been reduced by removal of endometrial caruncles prior to conception. Fetuses were studied between 120-140 days. When small they had much higher plasma catecholamine concentrations than normal which was closely related to plasma pH and PaO2. The increase was predominantly of noradrenaline. During hypoxia, caused by giving ewes(More)