title: Evidence for episodic secretion of testosterone in laboratory mice.
abstract: The concentration of testosterone (T) in the peripheral plasma of laboratory mice is extremely variable. This variability is already evident at 20--25 days of age and is not eliminated by brief or chronic exposure to male or female mice, or by isolation. The variation in T levels in plasma samples collected from the same animals on different occasions is comparable to the variation between individuals bled on a single occasion. The concentration of T in the testis is as variable as that in the peripheral plasma. It is suggested that in the laboratory mouse T is produced and released in an episodic fashion, that elevations in T levels in peripheral plasma of mice are greater than those observed in other species, and that testicular secretory episodes are interspersed with periods of minimal steroidogenic activity.
mesh_terms: D000375:Aging; D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks; D005260:Female; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012726:Sexual Behavior, Animal; D013737:Testis / Q000378:metabolism; D013739:Testosterone / Q000097:blood* / Q000378:metabolism
chemical_list: D013739:Testosterone