No abstract

1. The potential use of an extrinsic label to measure iron absorption from a ferric orthophosphate-fortified malted cocoa drink was examined by measuring the solubility of the FePO4 in 0·1 M-hydrochloric acid.2. The validity of using the stable isotope 58Fe as an extrinsic label was tested by comparing Fe absorption by rats from wheat flour extrinsically-labelled with 58Fe or 59Fe.3. Fe absorption from a malted cocoa drink (20 g powder made up with hot water) fortified with FePO4 (0·5 mg Fe/g powder) was measured in human subjects using 58Fe as an extrinsic label. Absorption was calculated by measuring unabsorbed 58Fe in faeces. Absorptions of Fe from the drink fortified with either FePO4 or ferrous sulphate were compared. The effect of the addition of ascorbic acid to the drink (1 mg/g powder) on Fe availability was also examined.4. The effect of fasting on Fe absorption from the drink was determined in rats by giving the drink to fasting animals or shortly after they had consumed a small meal.5. The FePO4 was totally soluble in 0·1 M-HCl and there were no differences in absorption between 58Fe- and 59Fe-labelled wheat flour. In the human experiment the proportion of Fe absorbed from the drink plus FePO4 and ascorbic acid was (mean with SE) 0·25 (0·02), from the drink plus FePO4 0·24 (0·02) and from the drink plus FeSO4 0·23 (0·03). Fasting had a significant effect on Fe availability; rats given the drink shortly after a small meal absorbed less than half as much Fe as those given the drink on a fasted stomach.6. It was concluded that the FePO4 used to fortify the malted cocoa drink was as well absorbed as FeSO4 but that the high levels of absorption were a reflection of the fasting condition of the subjects. The level of ascorbic acid was not great enough to enhance the availability of the FePO4 any further.

1 The cardiovascular effects of histamine were examined in dogs anaesthetized with pentobarbitone 2 The effect of histamine on heart rate, blood pressure, left ventricular pressure, dP/dt,,,nv, and dP/dt: IIT (integrated isometric tension) was compared in the presence and absence ofautonomic reflexes and blood pressure control. 3 In innervated animals with no attempt to control blood pressure, histamine produced dosedependent decreases in blood pressure and heart rate and either positive or negative inotropic actions. 4 When autonomic reflexes were abolished, this variability in inotropic response was reduced and histamine produced a slight positive inotropic response. There was a decrease in blood pressure and a positive chronotropic response to histamine. 5 When blood pressure was controlled and the cardiac nerves were intact, histamine produced a decrease in heart rate. However, in the denervated animals, there was a slight increase in heart rate. 6 Inotropic responses to histamine in the blood pressure controlled groups were less variable than when blood pressure was uncontrolled. In all of these animals there was an increase in contractility, the increase being more marked in the denervated group. 7 The H2-receptor agonist impromidine produced a positive inotropic action in intact animals with uncontrolled blood pressure.

Female rats were fed from weaning on diets with sucrose, starch, glucose or fructose as the carbohydrate source. Animals were killed at various stages throughout pregnancy and early lactation. Maternal plasma triglycerides (TG), cholesterol, free fatty acids, glucose, insulin and corticosteroids were measured. Lipogenic activity was assayed in the livers, adipose tissue and mammary tissue, and the results compared with those from non-pregnant rats. Insulin, corticosteroids and hepatic lipogenesis were also assayed in the embryos and in newborn pups. Dietary sucrose and fructose produced a significantly higher concentration of plasma TG in the non-pregnant, pregnant and lactating rats than did starch and glucose. All the diets led to an increase in TG concentration at the 20th day of pregnancy, which returned to the original concentration 2 days post-partum. The hypertriglyceridaemia of late pregnancy was accentuated by the feeding of sucrose and fructose. Maternal concentrations of plasma glucose were significantly reduced towards the end of pregnancy in all dietary groups. The replacement of starch by sucrose, or of glucose by fructose, enhanced hepatic lipogenesis. Fructose but not sucrose depressed fat synthesis in the adipose tissue. Hepatic fatty acid synthetase activity was increased in late pregnancy on all diets except that with starch. Late pregnancy intensified hepatic lipogenesis in rats fed sucrose or fructose. The results are discussed in relation to the metabolic changes during pregnancy and to sucrose feeding.