beta-endorphin and Fetal-Growth-Retardation

beta-Endorphin (beta-E) immunoreactivity was measured in the amniotic compartment of 52 normotensive and 45 hypertensive gestations. All the fetuses of the normal group were healthy and showed appropriate intrauterine growth, whereas only suffering and growth-retarded fetuses were included in the pathological group. As expected, amniotic beta-E concentration was found to be significantly higher in hypertensive than in normotensive pregnancies (mean +/- SEM: 129.1 +/- 8.15 vs. 59.1 +/- 2.68 pg/ml; p < or = 0.005). A positive correlation between the hormone levels and the diastolic as well as the mean maternal blood pressure (r: 0.554; p < or = 0.05 and r: 0.525; p < or = 0.05, respectively) was present only in pregnancies complicated by hypertension. Furthermore, a negative correlation (r: -0.555; p < or = 0.05) linked amniotic beta-E and the pulse pressure in normal but not in complicated pregnancies. Unless beta-E in the amniotic compartment is also of amniochorial origin, our results suggest that the fetal endorphinergic tone is either activated by elevated diastolic and mean maternal pressure levels or lowered by increased pulse pressure values in normally elapsing pregnancies.

Topics: Adolescent; Adult; Amniotic Fluid; beta-Endorphin; Blood Pressure; Female; Fetal Growth Retardation; Humans; Pre-Eclampsia; Pregnancy; Radioimmunoassay

The opioid polypeptide beta-endorphin is present in fetal blood but it is not clear whether its source is the fetus or the placenta. We therefore measured beta-endorphin in extracts of fetal femoral arterial and umbilical venous blood plasma in sheep by radioimmunoassay to determine whether the fetus or the placenta is the major source of beta-endorphin in the fetal circulation. Chromatographic analysis of extracts of fetal arterial plasma showed that beta-lipotropin and other precursors of beta-endorphin made only a minor contribution to the immunoreactivity detected. Concentrations of immunoreactive beta-endorphin were higher in the femoral artery than in the umbilical vein in fetal sheep between 113 and 128 days of pregnancy. Therefore the placenta removes beta-endorphin or a closely related polypeptide of fetal origin from the umbilical circulation in sheep at this stage of gestation. Acute hypoxaemia and hypoglycaemia increase the concentrations of immunoassayable beta-endorphin in blood plasma of adult and fetal sheep, but little is known about the effects of chronic hypoxaemia or hypoglycaemia on the circulating levels of beta-endorphin and related polypeptides in the fetus. Therefore we also measured immunoreactive beta-endorphin in blood plasma from fetal sheep in which growth retardation in association with restricted placental growth was produced by removal of endometrial caruncles before mating. Intra-uterine growth retardation was accompanied by chronic hypoglycaemia and chronic hypoxaemia in the fetuses. This was not associated with higher concentrations of beta-endorphin-like immunoreactivity in fetal arterial or umbilical venous plasma, but was accompanied by significantly increased placental extraction of fetal immunoreactive beta-endorphin from the umbilical circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; beta-Endorphin; Body Weight; Chromatography, Gel; Female; Femoral Artery; Fetal Blood; Fetal Growth Retardation; Organ Size; Placenta; Pregnancy; Pregnancy, Animal; Radioimmunoassay; Sheep; Umbilical Veins

Intrauterine growth retardation is a common and potentially hazardous problem for the fetus. Despite this, the obstetric factors associated with growth retardation have changed little in the last twenty years. Some of the other factors, the so-called behavioural factors should be amenable to correction through education or changing social circumstances. Experimental studies presented here support the clinical observations that the growth retarded fetus is often malnourished and/or hypoxaemic. Restriction of placental growth results in fetal growth failure and these fetuses are chronically hypoxaemic and hypoglycaemic. Furthermore the apparent margin of safety between the delivery to and consumption by the fetus is less for the small fetuses. We suggest that this reduction in supply results in the endocrine changes and that these in turn, modulate the pattern of fetal growth.

Topics: Animals; beta-Endorphin; Endorphins; Epinephrine; Female; Fetal Growth Retardation; Fetal Heart; Fetus; Glucose; Heart Rate; Humans; Hydrocortisone; Maternal-Fetal Exchange; Norepinephrine; Oxygen Consumption; Pregnancy; Prolactin; Rabbits; Rats; Reference Values; Sheep; Somatomedins; Thyroid Hormones; Thyroxine; Uterus

Amniotic fluid beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) were measured by radioimmunoassay after silicic acid extraction and gel chromatographic separation of the two peptides in uncomplicated second-trimester and term pregnancies, in diabetic patients at term, and in pregnancies complicated by Rh-isoimmunization, premature labor, and intrauterine growth retardation. Furthermore, the lecithin/sphingomyelin (L/S) ratios as well as the dehydroepiandrosterone sulfate (DHEA-S) and cortisol levels were determined in most of the amniotic fluid specimens. Both the mean (+/- SE) beta-EP (65.3 +/- 9.1 fmol/ml) and beta-LPH (150 +/- 15.8 fmol/ml) concentrations were significantly higher in the 20 patients with normal pregnancies of 16 to 21 weeks' duration than those found in 21 patients with uncomplicated term pregnancies of 38 weeks' gestation, averaging 42.6 +/- 6.0 and 80.1 +/- 10.7 fmol/ml, respectively. The mean amniotic fluid beta-EP and beta-LPH concentrations measured in the latter subjects were similar to those observed in 23 diabetic patients with otherwise uncomplicated term pregnancies. The mean amniotic fluid beta-EP and beta-LPH levels found in the limited number of patients with Rh-isoimmunization (N = 9), premature labor (n = 8), and intrauterine growth retardation (n = 5) with pregnancies of 24 to 36, 24 to 36, and 34 to 38 weeks' gestation, respectively, were not significantly different from the mean amniotic fluid beta-EP and beta-LPH concentrations of uncomplicated term pregnancies. In all patients but those with Rh-isoimmunization, beta-EP concentrations exhibited a positive correlation with beta-LPH levels. However, the molar beta-LPH:beta-EP ratio was significantly lower at term than during the early second trimester. Neither beta-EP nor beta-LPH correlated with the amniotic fluid L/S ratio and only beta-LPH exhibited a significant inverse correlation with amniotic fluid DHEA-S. The latter was significantly higher in uncomplicated term than second-trimester pregnancies. These results confirm that immunoassayable beta-EP is present in amniotic fluid and declines toward term. These data demonstrate that immunoassayable beta-LPH is present in amniotic fluid and show a more pronounced decrease toward the end of pregnancy than beta-EP. Neither peptide, at least on account of the amniotic fluid levels, appears to be associated with fetal maturation. The physiologic significance of amniotic fluid beta-EP and beta-LPH and their possibl

Topics: Amniotic Fluid; beta-Endorphin; beta-Lipotropin; Endorphins; Female; Fetal Diseases; Fetal Growth Retardation; Humans; Obstetric Labor, Premature; Pregnancy; Pregnancy in Diabetics; Pregnancy Trimester, Second; Pregnancy Trimester, Third; Radioimmunoassay; Rh-Hr Blood-Group System