Changes in pulsatile peripheral patterns of estradiol-17beta and progesterone during superovulation in Murrah buffaloes (Bubalus bubalis)

摘要

Oestrus was induced in 5 Murrah buffaloes by implantation of norgestomet (Crestar). Blood samples were taken at intervals of 15 min for 5 h during the induced oestrus (45 h after implant removal), the luteal phase of the oestrous cycle (day 10 of the cycle), superovulatory oestrus (43 h after administration of prostaglandin given as part of a superovulatory treatment) and 64 h after prostaglandin administration, to coincide with the periovulatory period. Ovulations were confirmed by ultrasonography. The mean plasma oestradiol-17beta (E2) concentration was 45.9±2.22 pg/ml during the induced oestrus and 8.6±0.49 pg/ml during the luteal phase. There was a marked increase in E2 level during the superovulatory oestrous period (73.7±4.41 pg/ml); the level dropped to 25.6±1.74 pg/ml around the period of superovulation. Pulse frequency (0.8 pulses/h), pulse amplitude (84.2±8.32 pg/ml) and basal concentration (30.6±2.59 pg/ml) during the superovulatory oestrous period were significantly higher than duringother phases studied in the experiment. Plasma progesterone (P4) concentration was significantly higher during the luteal phase (2.9±0.17 ng/ml) than during induced the oestrous period (0.8±0.05 ng/ml), and was 0.3±0.03 ng/ml during the superovulatory oestrous period. Pulse frequency, pulse amplitude and the basal progesterone concentration during the luteal period were higher than in other phases of the superovulation experiment. Synchrony of E2 and P4 pulses was observed. It was concluded that sex steroids are secreted in a pulsatile manner in buffaloes and that the induction of superovulation affects the pattern of secretion.