title: Changes in plasma growth hormone (GH) and secretion patterns of GH and luteinizing hormone in buffaloes (Bubalus bubalis) during growth.
abstract: To assess the changes of plasma growth hormone (GH) and secretion patterns of GH and luteinizing hormone (LH) during growth in buffaloes, six growing female Murrah buffalo calves (mean age 6+/-0.9 months and body weight 66+/-6 kg) were selected. Plasma samples were collected twice a week for 52 weeks for GH and LH assay. To examine for pulsatile secretion samples were collected at 15 minutes interval for 9 hr at weeks 6 and 42 for GH and LH measurements. Plasma progesterone was also estimated in twice-a-week samples to assess whether any of the buffalo had begun ovarian cyclicity. The body weight of all animals was recorded at weekly interval. Plasma GH concentration decreased (P < 0.01) only up to week 29 and showed an increasing trend (P < 0.01) thereafter. The ratio of plasma GH to body weight declined (P < 0.01) throughout the entire experimental period. Plasma GH showed a declining trend only up to when the animals attained 155 kg body weight and thereafter showed an increasing trend (P < 0.01). Plasma GH revealed distinct pulsatile patterns of release, with a mean of 6 and 5 pulses in the 6-week and 42-week samples, respectively. The plasma LH concentrations around the 42-week time period were significantly higher (P < 0.01) than at the 6-week time period, and they exhibited pulsatility. No animal reached puberty until the end of the experiment. In summary, plasma GH levels have a definite pattern of change during growth and patterns of secretion of plasma GH and LH also have a relation with body weight in this species of animal.
authors.affiliation: National Research Centre on Mithun (ICAR), Jharnapani, Medziphema, Nagaland, India. mohan_mondal@rediffmail.com
authors.forename: Mohan
authors.initials: M
authors.lastname: Mondal
authors.forename: B S
authors.initials: BS
authors.lastname: Prakash
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology; D002020:Buffaloes / Q000097:blood* / Q000254:growth & development*; D005260:Female; D013006:Growth Hormone / Q000097:blood* / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood* / Q000378:metabolism; D010507:Periodicity; D011374:Progesterone / Q000097:blood; D012741:Sexual Maturation / Q000502:physiology
chemical_list: D011374:Progesterone; D007986:Luteinizing Hormone; D013006:Growth Hormone