Synchronization of oestrus in adult female rats by utilizing the paradoxical effects of an LH-RH agonist

Abstract

Implantation of 25 μg per rat of an LH-RH agonist, [Des-Gly10, D-Ala6,ProNHEt9]LH-RH, contained within a cholesterol matrix pellet caused a complete and continued suppression of oestrus in rats within 3 days. Removal of the pellets after 7 days led to synchronized oestrus 4 days later in 90-95% of the animals (N = 30); the remaining animals became oestrous on the 5th day. Fertility of these treated rats mated at the synchronized oestrus was equivalent to that of a control, sham-operated population allowed to mate over a 3-day period.