Temporal relationship of spontaneous and coitus-induced release of luteinizing hormone in the normal cyclic rat
Moss, R.L.; Cooper, K.J.
Endocrinology 92(6): 1748-1753
1973
ISSN/ISBN: 0013-7227 PMID: 4707266 DOI: 10.1210/endo-92-6-1748Document Number: 492407
Changes in plasma LH were studied in cyclic unmated and mated female rats maintained on a modified lighting regime (lights on midnight to 14.00 h). In unmated animals, the critical period for LH release occurred 3-5 h prior to the onset of the dark cycle, a time comparable to that observed in the conventional light-dark cycle (lights on 05.00 to 19.00 h). A significant increase in LH concentration was observed in mated animals throughout the major portion of behavioural receptivity. Plasma LH was elevated within 10 min following cessation of mating, reached a maximum at 15-30 min, and remained elevated during the next hour. When rats were mated during the time that plasma LH was declining from the pro-oestrus peak, mating prevented the decline in LH which occurred in the controls. The results indicate that coitus can stimulate LH release in the female rat and that the response is related to the intensity of the female sexual behaviour.