EFFECT OF GESTATION ON GNRH-INDUCED LH AND FSH RELEASE IN BUFFALO (BUBALUS-BUBALIS)

This study examined the effect of gestation on the hypophyseal respons iveness of buffalo to GnRH-induced LH and FSH release. Peripheral plas ma LH and FSH concentrations were measured at 1 h before and up to 6 h after administration of GnRH (1 ug/kg body weight) or saline at Days 60, 150 and 240 of gestation in 2 groups of buffalo (n=4 each). Basal LH concentrations did not vary at the 3 stages of gestation, while bas al FSH concentrations exhibited a significant reduction (P<0.05) from Day 60 to Day 150 of gestation. There was a significant reduction in t he total LH (P<0.05) and FSH (P<0.01) released in response to GnRH fro m Day 60 to Day 240 of gestation. The duration of LH and FSH peaks and the time to attain peak concentration was not affected by the stage o f gestation. The results of the present study point to a progressive d ecline in LH and FSH release responses to GnRH during the advancement of gestation in the buffalo.