THE POSTNATAL DEVELOPMENT OF THE PITUITARY THYROTROPIN-RELEASING HORMONE RECEPTOR IN MALE AND FEMALE RATS

Abstract
The density of the pituitary TRH receptor in male and female rats was measured during postnatal development. The younger rats of both sexes exhibited higher [3H]TRH binding than did adults. A comparison of the properties of receptor binding between 4–5 day-old and adult pituitary showed that the increased binding was solely due to an increase in Bmax (maximum binding capacity) and not the KD (binding affinity). In conclusion, these findings demonstrate that the increased TRH-receptor density may be a contributing factor in eliciting exaggerated TSH response to exogenous TRH in neonatal rats.