Decreased Dietary Protein or Energy Intake and Plasma Growth Hormone Levels of the Pregnant Pig, its Fetuses and Developing Progeny

Atinmo, Tola; Baldijrao, C; Wg, Pond; Rh, Barnes

doi:10.1093/jn/106.7.940

Cited by 33 publications

(15 citation statements)

References 36 publications

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“…Growth hormone levels were high in all the fetuses. This finding is also consistent with the results of other workers [2,13] and with our results from anaesthetized fetuses and could be an anaesthetic effect, since some narcotics have been shown to increase growth hormone levels [10,30], The insulin levels were also considerably higher than expected in maternal blood and in the control and blank fetuses. It seems probable that this is also an effect of the anaesthesia, since it is unlike ly that there is transplacental movement of insulin in the pig.…”

Section: Discussionsupporting

confidence: 94%

Lack of Effect of Chronic Hyperinsulinaemia on Growth and Body Composition in the Fetal Pig

et al. 1983

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Chronic hyperinsulinaemia in the presence of euglycaemia was obtained in pig fetuses using implanted osmotic minipumps to deliver 3 U of insulin per day over 14 days (90–104 days gestational age); term is 114 days. Total body growth (length and weight) was unaffected by insulin administration, although some changes in organ weights were observed. There was a significant retardation of lung growth (apparently as a result of operative stress) and, in the insulin-treated fetuses, an increase in liver weight which was attributable to enhanced glycogen deposition. Two of the insulin-treated fetuses appeared to have an increase in subcutaneous fat at delivery, but overall there was no statistically significant change in body fat, water, or protein content of the carcases. Growth hormone levels in all the fetuses were high, but there were no differences between treatment groups. Bioassayable plasma somatomedin activity was increased in the insulin-treated fetuses. It is proposed that this increase may be a result of insulin-induced enhancement of liver growth hormone receptors. From these data we conclude that a 14-day period of hyperinsulinaemia towards the end of gestation does not stimulate growth of the pig fetus despite producing an increase in somatomedin activity. The growth enhancement seen in offspring from diabetic mothers is probably due to increased nutrient availability rather than a direct effect of fetal insulin. Insulin does, however, significantly increase glycogen deposition in the fetus.

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Section: Discussionsupporting

confidence: 94%

Lack of Effect of Chronic Hyperinsulinaemia on Growth and Body Composition in the Fetal Pig

et al. 1983

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“…How¬ ever, the wide variation in thyroxine levels found in the acute studies in the foetal pig threw some doubt on whether similar results would be found in the absence of anaesthetics and surgical stress. By contrast, the lack of change in growth hor¬ mone levels throughout this period of gestation is at variance with the indications obtained from cross-sectional data, obtained with an acute study, in the foetal pig (Atinmo et al 1976). The results obtained by these investigators suggested an increase in growth hormone concentrations in the blood of foetal pig between 91 and 105 days gestation.…”

Section: Discussionmentioning

confidence: 58%

“…This view is supported further by the findings that growth hormone levels in the foetal circulation change, particularly throughout the later stages of gestation (Grumbach & Kaplan 1973;Atinmo et al 1976).…”

mentioning

confidence: 82%

“…The fact that growth hormone is present in the circulation of the foetus at high concentrations (Bassett et al 1970;Oxender et al 1972;Atinmo et al 1976;Spencer et al 1983a) suggests that there is a role for the hormone in utero, especially since growth hormone does not cross the placenta. This view is supported further by the findings that growth hormone levels in the foetal circulation change, particularly throughout the later stages of gestation (Grumbach & Kaplan 1973;Atinmo et al 1976).…”

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confidence: 99%

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Plasma growth hormone and thyroxine levels in the chronically catheterised pig foetus and the effect of thyrotrophin releasing hormone

Macdonald¹,

Spencer²,

Hallett³

1985

Acta Endocrinologica

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The circulating levels of growth hormone and thyroxine during the last 2 weeks of gestation, and the effect of thyrotrophin releasing hormone on their secretion, has been examined in 13 chronically catheterised pig foetuses. Porcine growth hormone, measured by homologous radioimmunoassay, in the foetal plasma was found to average 83.5 \m=+-\10.3 ng/ml, while thyroxine levels were 92.9 \m=+-\4.1nmol/l. There was no change in thyroxine or growth hormone levels with gestational age. Injection of 5 \ g=m\ g TRH produced a marked increase in plasma growth hormone levels (+ 194 \m=+-\51 ng/ml) but no change in thyroxine was observed. Injection of saline and subsequent blood sampling had no effect on the levels of either growth hormone or thyroxine.Since growth is more rapid in utero than at any other time during the life of an animal, it seems likely that there would be some hormonal control of cell division in the foetus. Growth hormone, perhaps working through the somatomedins, is a likely canditate for this important role. It is clear that growth hormone is centrally involved in regu¬ lating growth in the post-natal animal even though its actions may be mediated and influenced by many other hormones. The role of growth hor¬ mone in stimulating growth in utero is, however, far from clear. Conflicting evidence is assessed differently by different authors. Thus Jost (1954, 1979) concludes that 'the pituitary gland has at most a slight effect on foetal (rat) growth' and

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“…Although growth hormone (GH) levels are much higher in the pig fetus than in the post-natal animal (Atinmo et al, 1976;Spencer et ai, 1983a) the reverse is true of the levels of insulin-like growth factor 1 (IGF-1 which are lower in the pig fetus (Spencer et al, 1983a(Spencer et al, , 1989a (Spencer et al, 1989b(Spencer et al, , 1991. However, in those studies it was not possible to determine the mechanism by which the intracerebroventricularly (icv) administered IGF-1 produced a decrease in circulating GH levels.…”

Section: Introductionmentioning

confidence: 99%

Decreased circulating growth hormone levels following centrally administered insulin-like growth factor-1 is not mediated by somatostatin in the pig fetus

Spencer¹,

Macdonald²,

Carlyle³

et al. 1991

Reprod. Nutr. Dev.

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Summary ― Twenty-six pig fetuses (at 94 days gestational age) were fitted with carotid artery catheters. Eight fetuses were given 1 500 ng of IGF-1 (in 100 pl) directly into a lateral cerebral ventricle; 7 further fetuses received the IGF-1 together with 150 pl of a potent specific anti-somatostatin serum into a ventricle, 5 other fetuses received the anti-somatostatin serum alone while 6 controls received normal sheep serum. Administration of IGF-1 caused a rapid decrease in circulating growth hormone (pGH) levels but there was no significant change in plasma levels of somatostatin immediately following the IGF-1 administration, suggesting that the decrease in pGH was not mediated by somatostatin secretion. Further evidence that somatostatin was not involved in this effect was provided by the lack of effect of concurrent antisomatostatin serum on the IGF-1-induced decrease in pGH. Thus the high circulating levels of GH in the fetus may result from a lack of feedback of IGF-1, but not through the somatostatin-pituitary axis.pig / fetus / IGF-1 / somatostatin / growth hormone Résumé ― La diminution des niveaux d'hormone de croissance circulante après administration centrale d'IGF-1 (insulin-like growth factor 1 ) n'est pas régulée par la somatostatine chez les foetus de porc. Vingt-six foetus de porc (à 94 j de la gestation) ont été équipés de catheters intracardotidiens. Huit d'entre eux ont reçu 1 500 ng d'IGF-1 pur (dans 100 J 11), directement dans un ventricule cérébral latéral; 7 autres ont reçu / 7 GF-? mélangé à 150 pl d'un puissant antiserum spéci-fique de la somatostatine dans un ventricule, 5 autres encore ont reçu l'antisérum seul tandis que 6 témoins recevaient serum normale. L'administration de l'IGF-1 a provoqué une chute rapide de la concentration de pGH circulante sans que simultanément soit noté un changement significatif du niveau plasmatiques de somatostatine ce qui suggère que la chute de pGH n'était pas due à une sé-crétion de somatostatine. Une autre preuve que la somatostatine n'intervient pas dans ce processus fut l'absence d'effet de l'antisérum anti-somatostatine sur la chute de pGH induite par l'IGF-1. Ainsi les niveaux élevés de GH circulante chez les foetus pourraient provenir non pas d'une absence de retrocontrôle par IGF-1 mais d'une immaturité de l'axe somatostatine-hypophyse foetale.

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Decreased Dietary Protein or Energy Intake and Plasma Growth Hormone Levels of the Pregnant Pig, its Fetuses and Developing Progeny

Cited by 33 publications

References 36 publications

Lack of Effect of Chronic Hyperinsulinaemia on Growth and Body Composition in the Fetal Pig

Lack of Effect of Chronic Hyperinsulinaemia on Growth and Body Composition in the Fetal Pig

Plasma growth hormone and thyroxine levels in the chronically catheterised pig foetus and the effect of thyrotrophin releasing hormone

Decreased circulating growth hormone levels following centrally administered insulin-like growth factor-1 is not mediated by somatostatin in the pig fetus

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