Role of Glucocorticoids in Fasting-induced Changes in Hypothalamic and Pituitary Components of the Growth Hormone (GH)-axis

• 영문명: Role of Glucocorticoids in Fasting-induced Changes in Hypothalamic and Pituitary Components of the Growth Hormone (GH)-axis
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Eunhee Kim Sanghee Seo Hyunju Chung Seungjoon Park
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제12권 제5호, 217~224쪽, 전체 8쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 2008.01.01

영문 초록

To directly test if elevated glucocorticoids are required for fasting-induced regulation of growth hormone (GH)-releasing hormone (GHRH), GHRH receptors (GHRH-R) and ghrelin receptors (GHS-R) expression, male rats were bilaterally adrenalectomized or sham operated. After 7 days, animals were fed ad libitum or fasted for 48 h. Bilateral adrenalectomy increased hypothalamic GHRH to 146% and decreased neuropeptide Y (NPY) mRNA to 54% of SHAM controls. Pituitary GHRH-R and GHS-R mRNA levels were decreased by adrenalectomy to 30% and 80% of sham-operated controls. In sham- operated rats, fasting suppressed hypothalamic GHRH (49%) and stimulated NPY (166%) mRNA levels, while fasting increased pituitary GHRH-R (391%) and GHS-R (218%) mRNA levels. However, in adrenalectomized rats, fasting failed to alter pituitary GHRH-R mRNA levels, while the fasting-induced suppression of GHRH and elevation of NPY and GHS-R mRNA levels remained intact. In fasted adrenalectomized rats, corticosterone replacement increased GHRH-R mRNA levels and intensified the fasting-induced decrease in GHRH, but did not alter NPY or GHS-R response. These data suggest that elevated glucocorticoids mediate the effects of fasting on hypothalamic GHRH and pituitary GHRH-R expression, while glucocorticoids are likely not the major determinant in fasting-induced increases in hypothalamic NPY and pituitary GHS-R expression.

키워드

Glucocorticoids Fasting Growth hormone-releasing hormone (GHRH) GHRH receptor Growth hormone secretagogue (GHS) receptor Adrenalectomy