title: Plasma inhibin levels in relation to steroids and gonadotrophins during oestrous cycle in buffalo.
abstract: The study was conducted on six Murrah buffalo synchronized and induced to oestrus. An indwelling catheter was placed in the jugular vein of each buffalo 4 days before the expected onset of the oestrus following the induced oestrus and blood samples were collected at 8 h intervals from each animal throughout the oestrous cycle. Plasma immunoreactive inhibin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol-17 beta and progesterone were estimated by radioimmunoassay to study the variations in the peripheral levels of these hormones and their inter-relationships in order to elucidate the feedback systems controlling them during the oestrous cycle of buffalo. Plasma inhibin levels ranged between 391.25 and 631.97 pg/ml during various phases of the oestrous cycle and were found to be higher than reported in cows. Peak LH and FSH levels during oestrus were 38.40 +/- 9.21 and 24.04 +/- 4.75 ng/ml, respectively and estradiol-17 beta and progesterone were 19.50 +/- 5.51 pg/ml and 0.61 +/- 0.25 ng/ml, respectively. The mean plasma inhibin concentration on the day of oestrus was 562.5 +/- 18.9 pg/ml. Levels of FSH in the plasma showed three mid-cycle elevations which corresponded to comparatively lower inhibin and elevated estradiol-17 beta levels during the same period. From this observation it was deduced that both inhibin and estradiol-17 beta have a feed-back regulatory effect on FSH secretion in buffalo.
authors.affiliation: Department of Animal Production Physiology, CCS Haryana Agricultural University, Hisar, India.
authors.forename: B
authors.initials: B
authors.lastname: Singh
authors.forename: V D
authors.initials: VD
authors.lastname: Dixit
authors.forename: P
authors.initials: P
authors.lastname: Singh
authors.forename: G C
authors.initials: GC
authors.lastname: Georgie
authors.forename: V P
authors.initials: VP
authors.lastname: Dixit
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000097:blood* / Q000502:physiology; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000097:blood* / Q000502:physiology; D004973:Estrus Synchronization; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007265:Inhibins / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone