title: Effects of chronic bromocriptine-induced hypoprolactinemia on plasma testosterone responses to human chorionic gonadotropin stimulation in normal men.
abstract: To study the role played by normal levels of plasma prolactin (PRL) in the secretion of testosterone (T) in the testes, we induced hypoprolactinemia with a daily dose of 5 mg bromocriptine administered orally in five normal men 20 to 35 years of age for 8 weeks. The basal PRL, T, luteinizing hormone, follicle-stimulating hormone, and maximum responses of plasma T to human chorionic gonadotropin (hCG) stimulation were measured every 2 weeks. Basal levels of plasma T were reduced in the 1st 2-week-long period of hypoprolactinemia. In the 4-week-long period of hypoprolactinemia, the maximal response of plasma T to hCG stimulation was significantly reduced. The findings suggest that normal levels of plasma PRL may play an important role in the secretion of T in the human testes in vivo.
authors.affiliation: Department of Medicine, Shimane Medical University, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Oseko
authors.forename: A
authors.initials: A
authors.lastname: Nakano
authors.forename: K
authors.initials: K
authors.lastname: Morikawa
authors.forename: J
authors.initials: J
authors.lastname: Endo
authors.forename: A
authors.initials: A
authors.lastname: Taniguchi
authors.forename: T
authors.initials: T
authors.lastname: Usui
mesh_terms: D000328:Adult; D001971:Bromocriptine / Q000008:administration & dosage / Q000494:pharmacology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004334:Drug Administration Schedule; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D012016:Reference Values; D013739:Testosterone / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin; D001971:Bromocriptine; D013739:Testosterone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone