Co-Authors:
Amir, D., Institute of Animal Science, A.R.O., The Volcani Center, P.O.B. 6, Bet Dagan 50-250, Israel
Pines, M., Institute of Animal Science, A.R.O., The Volcani Center, P.O.B. 6, Bet Dagan 50-250, Israel
Gacitua, H., Institute of Animal Science, A.R.O., The Volcani Center, P.O.B. 6, Bet Dagan 50-250, Israel
Ron, M., Institute of Animal Science, A.R.O., The Volcani Center, P.O.B. 6, Bet Dagan 50-250, Israel
Abstract:
Three adult Finn cross rams were bled at 30-min intervals for 7 h in March, May-June, August and November, and again at hourly intervals for 2 h after an intravenous injection of 50 μg of a GnRH analogue. Plasma testosterone concentrations were measured by radioimmunoassay. The mean testosterone level from 15 blood samples for each ram was highest in November and lowest in March. The episodic pulse pattern of testosterone secretion during the 7-h blood sampling periods was most evident, and more similar among rams in August and November, and less so in March and May. The mean testosterone concentration from the blood samples collected 1 and 2 h after GnRH injection was significantly higher in August-November than in March-June, but the ratio of the testosterone level after to that before injection was highest in March and lowest in November. © 1986.