title: 15alpha-hydroxytestosterone induction by GnRH I and GnRH III in Atlantic and Great Lakes sea lamprey (Petromyzon marinus L.).
abstract: The sea lamprey (Petromyzon marinus L.) represents one of the two most ancient classes of vertebrates and possesses a functional hypothalamus-pituitary-gonadal axis. However, the presence and functionality of androgens in the sea lamprey remain elusive. Recently, 15alpha-hydroxytestosterone (15alpha-T) has been found in sea lamprey gonads and blood plasma. In this study we examined changes of circulatory concentrations of 15alpha-T in response to gonadotropin releasing hormone (GnRH) treatments. Plasma concentrations of 15alpha-T in sea lamprey increased 2-5 times for all GnRH-injected sea lamprey compared to controls (P < 0.001). However, there were no differences among responses: (1) to the two forms of GnRH (lamprey GnRH I or lamprey GnRH III), (2) to the doses delivered (50, 100, or 200 microg/kg), or (3) between post-injection sample intervals (8 or 24 h). Between lampreys from the Atlantic Ocean and Great Lakes sites, two of seven GnRH form and dosage comparisons showed between-site differences, but were not believed to represent an overall between-site difference. These are the first data to show a response of a C19 steroid to GnRH stimulation in sea lamprey.
authors.affiliation: Department of Fisheries and Wildlife, 13 Natural Resources Building, Michigan State University, East Lansing, MI 48824-1222, USA.
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Young
authors.forename: Mara B
authors.initials: MB
authors.lastname: Bryan
authors.forename: Stacia A
authors.initials: SA
authors.lastname: Sower
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Scott
authors.forename: Weiming
authors.initials: W
authors.lastname: Li
mesh_terms: D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006915:Hydroxytestosterones / Q000378:metabolism*; D007798:Lampreys / Q000378:metabolism*; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives
chemical_list: D006915:Hydroxytestosterones; D009842:Oligopeptides; C448022:gonadotropin-releasing hormone-III; C097498:lamprey GnRH-I; D007987:Gonadotropin-Releasing Hormone; D011761:Pyrrolidonecarboxylic Acid; C035390:15-hydroxytestosterone