The "ram effect": new insights into neural modulation of the gonadotropic axis by male odors and socio-sexual interactions.

ABSTRACT: Reproduction in mammals is controlled by the hypothalamo-pituitary-gonadal (HPG) axis under the influence of external and internal factors such as photoperiod, stress, nutrition, and social interactions. Sheep are seasonal breeders and stop mating when day length is increasing (anestrus). However, interactions with a sexually active ram during this period can override the steroid negative feedback responsible for the anoestrus state, stimulate luteinizing hormone (LH) secretion and eventually reinstate cyclicity. This is known as the "ram effect" and research into the mechanisms underlying it is shedding new light on HPG axis regulation. The first step in the ram effect is increased LH pulsatile secretion in anestrus ewes exposed to a sexually active male or only to its fleece, the latter

SUBMITTER: Fabre-Nys C 

PROVIDER: S-EPMC4391029 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature