Luteinizing hormone receptors on granulosa cells from preovulatory follicles and luteal cells throughout the oestrous cycle of pigs.

摘要

Granulosa cells were isolated from porcine preovulatory follicles and luteal cells isolated without enzyme dissociation throughout the luteal phase, and in particular the period between the end of the follicular phase and the beginning of the lutealphase. The oestrous cycle phase was determined by morphological criteria. Five stages of the oestrous cycle were distinguished (preovulatory, and 1-3, 5-8, 8-10 and 12-14 days after ovulation). Highly purified hCG was iodinated and used in radioreceptorassays and autoradiographic studies. 31 autoradiograms from the 5 stages of the oestrous cycle were analysed. There were no significant differences in the equilibrium dissociation constant (KD) among all luteal cells. However the mean KD in luteal cellswas significantly lower than in granulosa cells. The number of LH/CG receptors per cell varied with the stage of the luteal phase. There were about 7300 LH/CG receptors/luteal cell isolated from a corpus luteum not later than 3 days after ovulation. When the corpora lutea matured, the number of LH/CG receptors/cell increased, reaching approximately a maximum of 28 400 per cell between the 8th and the 10th day of the luteal phase. Later, when the corpora lutea regressed, the number of receptors fell to17 400. There were many more LH/CG receptors on granulosa cells (76 600) than on luteal cells.