Impaired down-regulation of pituitary dopamine receptors by estradiol in aged rats.
Administration of 17 beta-estradiol to mature (6-12 months) rats results in a more than 50% reduction in pituitary dopamine receptor concentrations, without affecting binding affinity. In contrast, when the same manipulation is performed on senescent (24-25 months) rats, negligible change in receptor concentration occurs. These results suggest that age-related increases in estrogen-stimulated prolactin release are not due to decreased dopaminergic inhibition at the receptor level.
Kochman
K
K
Molecular Physiology and Genetics Section, Francis Scott Key Medical Center, Baltimore, Maryland 21224.
Joseph
J A
JA
Blackman
M R
MR
Stagg
C A
CA
Roth
G S
GS
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015536:Down-Regulation / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D010052:Ovariectomy; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011388:Prolactin / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*
D011954:Receptors, Dopamine; D004958:Estradiol; D011388:Prolactin