Abstract
Neonatal rats which had received a daily injection of 50 microgram of 2,4-dinitrophenol (DNP) or 30 microgram of L-thyroxine (T 4) for 7 days 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 T 4 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 T 4 rats compared with neo saline control rats. A small dose of T 4 injection, however, did not bring any difference on plasma TSH levels between neo T 4 and neo saline control rats while neo DNP rats showed a little blunted response of pituitary compared with neo T 4 and neo saline rats. Pituitary contents of TSH in neo T 4 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 T 4 rats than in neo DNP rats.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
