Human Cord Blood Concentrations of Thyrotropin, Thyroglobulin, and Iodothyronines after Maternal Administration of Thyrotropin-Releasing Hormone*

Roti, Elio; Gnudi, A; Braverman, Lewis E.; Robuschi, G.; Emanuele, Rossella; Bandini, Patrizia; Benassi, L; Pagliani, Attilio; Emerson, Charles H.

doi:10.1210/jcem-53-4-813

Cited by 83 publications

(18 citation statements)

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“…This brisk TSH response seen in our hyperbilirubinaemic newborns immediately after exchange transfusion has to our knowledge not been shown previously and is similar to that seen in our control population of healthy newborns after TRH stimulation, as well as to that reported in other studies in healthy newborns [2,6,16]. These results indicate that hyperbilirubinaemic newborns undergoing exchange transfusion are capable of responding adequately to acute TRH stimulation and have an intact pituitary-thyroidal axis.…”

Section: Discussionsupporting

confidence: 91%

Evaluation of the pituitary-thyroidal axis in newborns undergoing exchange transfusion

et al. 1986

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To evaluate whether the hypothyroxinaemia, previously noted in hyperbilirubinaemic newborns immediately after exchange transfusion for Rh or AB0 incompatibility, was due to impairment in the secretion of thyroid stimulating hormone (TSH) by the pituitary, we studied the thyroid hormone response to thyrotropin releasing hormone (TRH) and compared this response to that seen in a control population of healthy neonates. All infants studied responded with a brisk TSH increase; 30 min after TRH injection the mean TSH concentration of the hyperbilirubinaemic patients was 37 microU/ml, ten times their basal level, which was not different from the value noted in the control population. No significant change in total thyroxine (T4), 3,5,3' triiodothyronine (T3), free thyroxine (FT4) or 3,3',5' triiodothyronine (rT3), (FT4) or (rT3) was noted after TRH administration in either group of neonates. In addition the effect of exchange transfusion on the thyroid axis of hyperbilirubinaemic newborns was evaluated. Before the exchange transfusion TSH, T4, rT3, T3 and FT4 levels were higher in the hyperbilirubinaemic newborns than in donor blood; immediately post-exchange transfusion TSH and T4 concentrations of the hyperbilirubinaemic neonates decreased significantly and remained significantly below pre-exchange values 30 h later. Newborns undergoing an exchange transfusion respond appropriately to TRH stimulation and seem to have an intact pituitary-thyroidal axis.

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Section: Discussionsupporting

confidence: 91%

Evaluation of the pituitary-thyroidal axis in newborns undergoing exchange transfusion

et al. 1986

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“…The relative independence of this aspect of lung development from any fixed developmental program and its ability to respond to hormones at a very early stage of gestation may be important factors in determining the severity of respiratory disease in those very small preterm infants who have had insufficient prenatal exposure to T3 and hydrocortisone. Since cortisol and T3 concentrations can be manipulated both pre- (27,28) and postnatally, it may be possible to use these hormones to enhance the lung liquid reabsorptive capacity of the immature lung. seen during this part~of gestation (4) rather than a T3/hydrocoT-5.…”

Section: Hormone Concentrations and Timing Of Reabsorptive Responsementioning

confidence: 99%

Synergistic Action of Triiodothyronine and Hydrocortisone on Epinephrine-Induced Reabsorption of Fetal Lung Liquid

et al. 1990

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ABSTRACT. The influence of triiodothyronine and hydro-However, precocious exposure of the fetus to T3 at an early cortisone on maturation of the response to epinephrine that gestation did not significantly advance the time of appearance of leads to reabsorption of lung liquid was investigated in nine this reabsorptive capacity, from which it could be concluded that chronically catheterized fetal sheep. Experiments were some other factor must play a role in determining its maturation performed on thyroidectomized fetal sheep at 116-120 d during gestation. Steroid hormones, alone or in combination gestation, well before the reabsorptive response to epi-with thyroid hormones, are known to be important in determinnephrine is normally seen. After i.v. administration of ing the maturation of structural aspects of the lung and its either triiodothyronine (60 ~g / d ) or hydrocortisone (10 mg/ surfactant system in the fetus (8, 9). Our experiments were d) for 3 d (three fetuses in each case), all fetuses continued undertaken to examine the influence of hydrocortisone alone to secrete lung liquid during exposure to epinephrine (se-and in combination with T3 on the maturation of the reabsorpcretion rate = 5.9 f 3.2 mL/h in triiodothyronine-treated tive response. Fetal sheep were studied at 116-120 d, which is a and 4.4 2 1.9 mL/h in hydrocortisone-treated fetuses). gestation well before that at which the reabsorptive response to However, when the two hormones were administered to-epinephrine normally appears. gether in the same doses to three fetuses, a striking reabsorptive response to epinephrine was seen (absorption rate MATERIALS AND METHODS= -12.3 f 3.6 mL/h), similar to that observed in the mature fetus. Induction of this capacity to reabsorb lung Experimental preparation. The surgical preparation of chronliquid may be of importance in the management of respi-ically-catheterized fetal sheep to allow for repeated measurement ratory problems of the newborn infant. (Pediatr Res 27: of lung liquid secretion or absorption rate was identical to that 588-591,1990) described in detail by Walters and Olver (3). Nine dated, pregnant ewes were operated on at 1 12-1 15 d gestation under general Abbreviations anesthesia induced by thiopentone and maintained with fluothane. Fetal thyroidectomy was carried out and wide bore (inner T3, triiodothyronine diameter, 2.6 mm) catheters placed into each end of the incised T4, thyroxine fetal trachea, finer gauge catheters were inserted into the carotid TRH, thyrotropin-releasing hormone artery and jugular vein. The catheters were brought out through the uterus and flank of the ewe and the tracheal catheters joined to form an external loop that allowed uninterrupted flow of lung liquid from the fetal lung to the larynx between experiments. After surgery, antibiotics were given for the first 48 h to the ewe The secretion of lung liquid by the pulmonary epithelium (streptomycin 500 mg intramuscularly, benzyl penicillin 300 mg maintains expansion and promotes development of the fetal lung int...

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“…(18) also found that maternal administration of TRH resulted in peak fetal serum TSH values 40-60 min after the infusion; thereafter serum TSH showed a steady decline. Maximal stimulation of the fetal thyroid occurred about 2 h after the maternal injection of TRH.…”

Section: ------------------------- Tmentioning

confidence: 76%

“…Intraamniotic injection of thyroid hormones, however, does result in higher fetal levels (33). TRH, on the other hand, crosses the placenta readily and stimulates the fetal pituitary (16)(17)(18).…”

Section: ------------------------- Tmentioning

confidence: 99%

“…For these reasons, the use of combined hormonal treatment with g1ucocorticoids and thyroid hormones to enhance fetal lung maturation has been proposed (14,15). Such treatment could involve the use of TRH, which, unlike thyroid hormones, crosses the placenta readily and evokes secretion of fetal TSH, T 3 , and T 4 in humans and laboratory animals (16)(17)(18). TRH alone also has been shown to increase surfactant secretion in fetal rabbits (19).…”

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Response of the Maternal, Fetal, and Neonatal Pituitary-Thyroid Axis to Thyrotropin-Releasing Hormone

Moya

Mena

Heusser³

et al. 1986

Pediatr Res

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ABSTRACT. Thyrotropin releasing hormone (TRH) readily crosses the placenta and stimulates the fetal pituitary. We studied the response of the maternal and fetal pituitarythyroid axes to TRH and the influence of prenatal exposure to TRH on the physiological postnatal increase in thyrotropin (TSH) and triiodothyronine (T 3 ) in the neonate. Twenty-six pregnant women received TRH (400 or 600 ILg) intravenous or saline (controls) either 2 or 12 h before elective cesarean section at term. Administration of 400 ILg of TRH resulted in significant elevations of maternal TSH (15.7 ± 2.9 versus 3.2 ± O.4ILU/ml,p < 0.01) and prolactin (416 ± 94 versus 223 ± 41 nglml, p < 0.05) 2 h later.Maternal T 3 remained unchanged. A higher dose of TRH (600 ILg) produced comparable results. Maternal administration of TRH (400 ILg) 2 h before delivery resulted in significant increases in fetal TSH and T 3 over controls (21.1 ± 3.7 versus 4.8 ± 1.0 ILU/ml, and 132 ± 12 versus 64 ± 9 ngldl, p < 0.01, respectively). Cord blood hormone levels 12 hours after TRH administration were similar to controls. Higher doses of TRH did not produce further increases in fetal TSH or T 3 • Control and treated neonates demonstrated similar physiological postnatal increases in TSH and T3, suggesting that prior exposure to TRH did not blunt this response. These data suggest that maternal administration of TRH is an effective way of increasing fetal T 3 levels, and that this treatment does not inhibit the postnatal surge in TSH and T 3 • (Pediatr Res 20: 982-986, 1986)

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Human Cord Blood Concentrations of Thyrotropin, Thyroglobulin, and Iodothyronines after Maternal Administration of Thyrotropin-Releasing Hormone*

Cited by 83 publications

References 0 publications

Evaluation of the pituitary-thyroidal axis in newborns undergoing exchange transfusion

Evaluation of the pituitary-thyroidal axis in newborns undergoing exchange transfusion

Synergistic Action of Triiodothyronine and Hydrocortisone on Epinephrine-Induced Reabsorption of Fetal Lung Liquid

Response of the Maternal, Fetal, and Neonatal Pituitary-Thyroid Axis to Thyrotropin-Releasing Hormone

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