@conference {40733,
	title = {Growth Hormone (GH) secretory patterns in genetically lean and fat sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {272-274},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The pattern of GH secretion was studied in Coopworth sheep which  have been selected for low (Lean) or high (Fat) ultrasonic backfat depth over  15 years. At each of two developmental stages (February and May) Lean and  Fat ram lambs were fed ad libitum or fasted for 48 hours (n=6 per treatment).   Animals were blood sampled via an indwelling jugular cannula every 10  minutes for six hours, then slaughtered and the pituitary glands removed and  weighted.   Mean GH was greater for Lean than Fat animals (2.82 versus 1.42 ng/ml,  p<0.001), in February than in May (2.47 versus 1.62 ng/ml, p<0.001) and for  fasted than fed animals (2.48 versus 1.62 ng/ml, p<0.001). Analysis of GH  secretory patterns showed that peak frequency for Lean animals was more  than twice that for Fat animals (2.64 versus 1.17 peaks/6 hours, p<0.001).   There was no difference in the peak amplitude. In line with their higher GH  concentrations, Lean animals had significantly heavier pituitaries than Fat  animals (0.74 versus 0.52 g, p<0.001).   Selection for leanness in Coopworth sheep has altered the GH secretory  pattern of the animals. The pituitary weight may explain some of these  changes in GH secretion.  },
	issn = {1176-5283},
	author = {Francis SM and Veenvliet BA and Littlejohn RP and Stuart SK and Suttie JM}
}
