Histological Study of Bovine Corpora Lutea

Abstract

Corpora lutea removed at various times during the cstrous cycle were studied after no treatment, treatment with oxytocin, oxytoein and HCG, oxytoein and bovine LH, and with HCG alone. These studies supported a hypothesis that luteal cells are derived from both granulosa and theca interna layers of the follicle. The granulosa-derived luteal cells develop into functioning luteal cells by about Day 4 of the estrous cycle, after which they undergo no further divisions. Therefore, granulosa-derived cells have limited potential. However, the smaller luteal cells derived from the theca interna respond to plasma luteotropin, multiply and grow into large luteal cells. These are mainly responsible for growth of the corpus luteum following Day 4.