Studies on the Effect of Neonatal Hypermetabolism on Hypothalamo-Pituitary-Thyroid Axis in Adult Rats
1979 年 26 巻 1 号 p. 27-34
詳細
1979 年 26 巻 1 号 p. 27-34
Neonatal rats which had received a daily injection of 50μg of2, 4-dinitrophenol (DNP) or 30μg of L-thyroxine (T4) for7days beginning on the day of birth were compared as to the late effect of the hypothalamo-pituitary-thyroid axis with the neo saline control. Neo DNP rats and neo T4 rats revealed the retardation of growth compared with neo saline rats. The plasma level of TSH in both groups presented its low response following TRH administration. Furthermore, plasma TSH levels following the challenge of PTU were depressed in both neo DNP and neo T4 rats compared with neo saline control rats. A small dose of T4 injection, however, did not bring any difference on plasma TSH levels between neo T4 and neo saline control rats while neo DNP rats showed a little blunted response of pituitary compared with neo T4 and neo saline rats. Pituitary contents of TSH in neo T4 rats decreased, but not in neo DNP rats. These results suggest that neonatal hypermetabolism causes the hypofunction of pituitary-thyroid axis through adult life and that the alteration of hypothalamus may be more obvious in neo T4 rats than in neo DNP rats.
