The function of the thyroid pituitary axis was investigated in 8 anencephalic infants with no hypothalamus. Thyrotrophin (TSH), thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine (reverse T3, rT3) were measured in the cord blood in 5 cases and during the first 4 h of life in 3 cases. TSH response to synthetic thyrotrophin-releasing hormone (TRH) (200 μg iv) was carried out in two cases and thyroid hormone response to bovine TSH (5 IU iv) was evaluated in 3 cases. The following results were obtained: 1) The pituitary gland was found in all infants and the thyroid was normal both grossly and by microscopic sections. 2) TSH levels at birth were normal but there was no spontaneous post-delivery surge. 3) T4 and T3 values at delivery were within normal range, but no T3 increase was present after birth. rT3 levels at birth were higher than normal in 3 cases. 4) Administration of TRH caused a marked and rapid TSH release. 5) Thyroid hormone response to TSH was normal. The present findings suggest that in the anencephalic foetus both pituitary TSH-secreting cells and the thyroid gland do develop despite the absence of the hypothalamus and are able to function if adequately stimulated.
Thyroid-pituitary function in eight anencephalic infants / S., Grasso; Filetti, Sebastiano; D., Mazzone; V., Pezzino; R., Vigo; R., Vigneri. - In: ACTA ENDOCRINOLOGICA. - ISSN 0001-5598. - STAMPA. - 93:4(1980), pp. 396-401.
Thyroid-pituitary function in eight anencephalic infants
FILETTI, SEBASTIANO;
1980
Abstract
The function of the thyroid pituitary axis was investigated in 8 anencephalic infants with no hypothalamus. Thyrotrophin (TSH), thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine (reverse T3, rT3) were measured in the cord blood in 5 cases and during the first 4 h of life in 3 cases. TSH response to synthetic thyrotrophin-releasing hormone (TRH) (200 μg iv) was carried out in two cases and thyroid hormone response to bovine TSH (5 IU iv) was evaluated in 3 cases. The following results were obtained: 1) The pituitary gland was found in all infants and the thyroid was normal both grossly and by microscopic sections. 2) TSH levels at birth were normal but there was no spontaneous post-delivery surge. 3) T4 and T3 values at delivery were within normal range, but no T3 increase was present after birth. rT3 levels at birth were higher than normal in 3 cases. 4) Administration of TRH caused a marked and rapid TSH release. 5) Thyroid hormone response to TSH was normal. The present findings suggest that in the anencephalic foetus both pituitary TSH-secreting cells and the thyroid gland do develop despite the absence of the hypothalamus and are able to function if adequately stimulated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.