[Sex differences and regulatory mechanism of epidermal growth factor receptor in the rat liver].
The number of epidermal growth factor (EGF) receptor in rat hepatic membranes was about 2-hold higher in adult male than in adult female rats. Castration of adult males slightly decreased the EGF receptor number. Castration of neonatal males decreased the number of EGF receptors when they reached sexual maturity. This decrease was restored by the combination of neonatal and pubertal treatments with testosterone. Hypophysectomy caused a marked decrease in the number of EGF receptors in the male animals, and this decrease was not restored by either testosterone or triiodothyronine administration. Continuous administration of human growth hormone (hGH) with an osmotic minipump to normal males reduced the EGF receptor number. In contrast, intermittent administration of hGH twice a day (every 12 hr) to hypophysectomized males and/or normal females significantly increased the EGF receptor number. These results indicate that the number of EGF receptors in rat hepatic membranes is regulated by the secretory rhythm of GH in the pituitary, which may be "imprinted" by neonatal androgen.
Kashimata
M
M
Department of Dental Pharmacology, Meikai University School of Dentistry, Saitama, Japan.
Hiramatsu
M
M
Minami
N
N
D000818:Animals; D002369:Castration; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology / Q000502:physiology; D007016:Hypophysectomy; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012727:Sex Characteristics; D013739:Testosterone / Q000494:pharmacology
D013739:Testosterone; D004815:Epidermal Growth Factor; D013006:Growth Hormone; D066246:ErbB Receptors