[Basal and LH-RH-stimulated gonadotropin release after transport stress in male rats].

A total of 120 male rats of the Sprague-Dawley-strain (6 weeks old) were used in this experiment. 5 groups of 12 animals each were treated intraperitoneally with 200 ng gonadotropin releasing hormone (LH-RH) per animal. 30 minutes later blood was sampled by heart puncture. Group I were animals without transport, group II immediately after, group III one day, group IV one week and group V six weeks after a standardised transport. Another 5 groups were subjected to the same protocol but received saline i.p. instead of LH-RH. Serum levels of LH and FSH were estimated by radioimmunoassay. LH and FSH serum levels could be stimulated by LH-RH in all groups. A significant rise of basal and LH-RH stimulated LH levels was observed until the first day after transport. Thereafter a drop was registered. No consistent patterns of basal as well LH-RH stimulated FSH-levels were noted. These data combine to suggest an elevation of LH-RH secretion as response to the stress. This results in a sensibilisation of the pituitary to exogenous LH-RH.