Profiles of plasma androgens in quail following testosterone injection at two different times of day.
Adult castrated male Japanese quail (Coturnix japonica) housed on an 8L:16D light-dark cycle (lights on at 0700 hr) were given a single injection of either 100 or 500 micrograms testosterone (T) at either 0800 or 1430 hr. Blood samples were taken 1, 3, 5, 7, or 24 hr after injection and assayed for androgens. Additional samples were taken from intact males housed on a 16L:8D light-dark cycle and from castrated males housed on 8L:16D and injected with the oil vehicle. With the 100-micrograms dosage, T and total androgen fell to the level of the intact males by 3 hr after injection and fell to the level of oil-injected castrates by 5 to 7 hr. With the 500-micrograms dosage, T and total androgen, though initially quite high, reached intact levels by 3 hr when birds were injected at 0800 hr but not until 5 hr when injected at 1430 hr, and T reached castrate levels by 5 hr following injection at 0800 hr but not until 24 hr following injection at 1430 hr. T levels after a 500-micrograms injection at 0800 hr were significantly higher 3, 5, and 7 hr later than T levels after the same injection at 1430 hr. Thus changes in plasma T levels over time following an injection of T depend on the time of injection, and plasma T remains above castrate levels for a shorter time when T is given in the bird's morning than when given just before lights-off. This can probably be explained by a greater rate of metabolism during lights-on compared with lights-off.
Adkins-Regan
E
E
Department of Psychology, Cornell University, Ithaca, New York 14853.
Ottinger
M A
MA
D000728:Androgens / Q000097:blood*; D000818:Animals; D003370:Coturnix / Q000097:blood*; D007700:Kinetics; D008297:Male; D011784:Quail / Q000097:blood*; D013739:Testosterone / Q000097:blood / Q000494:pharmacology*
D000728:Androgens; D013739:Testosterone