A. Dalkin, Gregory A. Bourne, D R Pieper
May 1, 1981
Citations
2
Influential Citations
84
Citations
Quality indicators
Journal
Endocrinology
Abstract
The gonadotropin-releasing hormone (GnRH) agonist D-Ala6-des-Gly10-GnRH ethylamide (D-Ala analog) was used as ligand to study GnRH receptors in the pituitary and gonads during sexual maturation in the rat. The affinities of the GnRH receptor (Ka = 6.5 × 109 M-1) were similar in all three tissues and did not change during maturation. Pituitary GnRH receptor concentration increased 2-fold in both sexes. Peak values occurred earlier (20 days) and were higher (720 ± 52 fmol/mg protein) in females than in males (30 days; 594 ± 54 fmol/mg). The changes in GnRH receptors followed a pattern similar to that of plasma FSH, though GnRH receptors were maximal 10 days after the FSH peak. The binding capacity of the gonadal GnRH receptors also changed with age, and was maximal on day 20 in females (271 ± 25 fmol/mg) before declining to a constant level by day 60 (139 ± 20 fmol/mg). In males, binding to testicular interstitial tissue was not detectable at 30 days of age but increased rapidly to 256 ± 13 fmol/mg by 40 da...