Distribuzione delle subunità alfa, beta A e beta B dell'inibina/activina nell'ovaio di cagna

The expression of inhibin/activin alfa, betaA and betaB subunits has been investigated by immunohistochemistry in the ovary of bitches. The granulosa cells of follicles at all stages of maturation were the main source of ovarian inhibin/activin. However, the corpus luteum and the intertitial gland cells were also involved in the synthesis of these hormones. The alpha inhibin expression decreased sharply in preovulatory follicles and inncreased in the corpus luteum reaching its highest level in the mid-luteal phase of the canine oestrus cycle. Inhibin/activin betaA and betaB subunit immunostaining was less intense than the alpha subunit, but it was an invariable feature. The theca interna layer, oocytes and surface epithelium immunostained only for betaA and betaB subunits. These findings suggest that inhibin/activin alfa, betaA and betaB subunits may play an important role in the regulation of the canine oestrus cycle, as previously reported in other species.