外源性生長激素刺激素對發身前與發身後貓隻生長激素調控之作用

外文標題: 
The effect of exogenous growth hormone releasing hormone on the regulation of growth hormone in prepubertal and pubertal cats
校院系所: 
中興大學 獸醫學系暨研究所
指導教授: 
李衛民
出版年份: 
2008年
主題類別: 
摘要: 

生長激素刺激素是一種從下視丘分泌出來的縮氨酸,它能刺激腦下垂體前葉的生長激素分泌細胞分泌生長激素。生長激素是一種調控身體生長、身體發育與身體組成的主要荷爾蒙。生長激素是呈現脈搏式的分泌方式,并於大多數的動物呈現性別上的差異。生長激素的分泌同時受到年齡、性別、身體組成等因素的影響。在此次的實驗的目的,我們主要是針對外源性生長激素刺激素對於發身前與發身後貓隻腦下垂體釋放生長激素的觀察,以及不同劑量生長激素刺激素對發身後腦下垂體分泌生長激素的影響。結果顯示使用1 μg/kg 生長激素刺激素並不會於發身前與發身後貓隻提升生長激素分泌,同時2 and 4 μg/kg 生長激素刺激素也不會提升發身後貓隻生長激素分泌。公貓與母貓的基礎生長激素濃度並無顯著性差異。雖然胰島素樣生長因子-I並不會因為生長激素刺激素的使用而增加,但是發身後母貓隻的胰島素樣生長因子-I低於公貓,并達到顯著性差異,同樣的,發身前公貓的胰島素樣生長因子-I濃度顯著高於同時期的母貓。在此實驗中並無觀察到血糖與血漿中可體松濃度,會因為生長激素刺激素的刺激而有所不同。因此於此實驗顯示無論於發身前或是發身後貓隻的生長激素、胰島素樣生長因子-I、血糖以及血漿中可體松的濃度,並不會因為生長激素刺激素的刺激而有所改變。同時,胰島素樣生長因子-I 濃度的不同具有性別上的差異,而且是從發身前就已經發現到了。胰島素樣生長因子-I 的濃度會隨著年齡的增加而遞減。

外文摘要: 

Growth hormone releasing hormone (GHRH) is a hypothalamic peptides that stimulates GH secretion. Growth hormone (GH) is a major regulator of growth, somatic development and body composition; it is secreted in a pulsatile manner which is sexually dimorphic in most mammalian species, and affected by age, gender, body composition and so on. In this study, we aim to investigate the GH response to exogenous GHRH for determining pituitary functions in the cats (4 females, 4 males) in different age (5, 11, 17, and 21 months). Different doses of GHRH (1, 2, and 4 μg/kg) were infused intravenously in pubertal cats. The administration of 1 μg/kg GHRH did not result in the change of plasma GH level in both prepubertal and pubertal cats, as well as 2 and 4 μg/kg GHRH in pubertal cats, and there were no significant different in basal plasma GH level between male and female cats. Although the change of plasma IGF-1 level after GHRH administration was not observed, however, we found that pubertal female cats had significantly lower basal plasma IGF-1 level than prepubertal period (p