Some aspects of equine placental exchange and foetal physiology

Silver, M.

doi:10.1111/j.2042-3306.1984.tb01917.x

Cited by 27 publications

(19 citation statements)

References 25 publications

(27 reference statements)

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“…Since it is the neutral amino acids that are primarily used for oxidative metabolism (Lemons, 1979;Milley, 1989) these observations suggest that there may be species differences in the rate of amino acid oxidation in utero. The fetal foal has a lower rate of urea production and a greater requirement for glucose than the fetal lamb and may therefore be less dependent on amino acid oxidation to maintain its metabolic balance during late gestation (Silver, 1984;. Alternatively, the differences in amino acid levels observed between the fetal foal and lamb may reflect species differences in the rate and type of protein accumulated by the fetus during late gestation.…”

Section: Discussionmentioning

confidence: 99%

Blood amino acids in the pregnant mare and fetus: the effects of maternal fasting and intrafetal insulin

Silver¹,

Fowden²,

Taylor³

et al. 1994

Experimental Physiology

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SUMMARYBlood amino acids were measured in twelve chronically catheterized mares and fetuses between 250 and 310 days gestation. The concentrations of the majority of individual amino acids were similar in maternal and fetal arterial blood and no gestational changes were detected. Only methionine, phosphoserine, 3-methyl-histidine and glutamine were consistently higher in the fetus than the mare, whilst certain other amino acids were higher in the maternal blood. Fasting the mares for 36 h led to significant falls in plasma glucose and rises in urea and maternal free fatty acids (FFA). Small but significant decreases in a few amino acids were seen in both fetus and mother, with an overall amino acid fall of 15 % in the fetus and 13 % in the mare. Virtually all amino acids had risen to basal values by 6 h after feeding. Intrafetal insulin (1 i.u./kg i.v.) as a bolus caused a more dramatic fall in fetal glucose than fasting, with no change in the mare. There were also rapid decreases in many amino acids by 30 min post-insulin and by 2 h all but five amino acids had fallen significantly. There was a drop in total fetal blood amino acids of 29 %. These findings show that, in contrast to most other species studied, there is no overall feto-maternal gradient in blood amino acids in the mare, and that fasting leads to small falls in amino acid concentration, whereas intrafetal insulin induces a severe hypoglycaemia with dramatic decreases in almost all amino acids and no change in urea, suggesting a direct anabolic effect of insulin on fetal tissues.

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Section: Discussionmentioning

confidence: 99%

Blood amino acids in the pregnant mare and fetus: the effects of maternal fasting and intrafetal insulin

Silver¹,

Fowden²,

Taylor³

et al. 1994

Experimental Physiology

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“…Fructose is found in the fetal circulation and fluid sacs of ruminants and certain other species such as the pig and horse. Fetal plasma concentrations of fructose range from 3.0 to 8.0 mmol/l in these species with virtually no detectable fructose in the maternal plasma (Silver 1984). Fructose is made from glucose in the placenta and its concentration in the fetus rises with increases in the fetal glucose level in the pig, sheep and horse (Silver 1984;McGowan et al 1995).…”

Section: Fructose Metabolismmentioning

confidence: 97%

Comparative aspects of fetal carbohydrate metabolism

Fowden

1997

Equine Veterinary Journal

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“…These first appeared in the early 1980s when reviews were published in the main volumes, as well as in Supplements usually devoted to single topics or groups of topics. Examples of the former are J.R. Holmes' (1982) article on ‘The circulation’ and M. Silver's (1984) on the equine placenta and fetal physiology. The recognition that the neonate is not just a very small adult in its physiology and response to drugs, which was a major step in understanding and occurred in both veterinary (especially equine) and human medicine during this period, was highlighted in this journal by papers such as Baggot and Short (1984) and Webb et al .…”

Section: Progress In Literary Form 1968–2010mentioning

confidence: 99%

“…Perinatology has featured in EVJ over the past 25 years and a special issue on equine perinatal physiology and medicine comprised Number 4 of Volume 16. This addressed the fetal/maternal relationship in reviews of equine placental exchange and fetal physiology (Silver 1984), maternal and fetal endocrinology during late pregnancy and foaling, carbohydrate metabolism during pregnancy (Fowden et al . 1984a) and the renin‐angiotensin system (Broughton Pipkin 1984).…”

Section: Perinatal Physiology and Medicinementioning

confidence: 99%