Effect of neonatal thyroidectomy on growth hormone secretion in the rat

Kitauchi, Shintaro; Yamanouchi, Hiroshi; Hirano, Naomi; Tone, Sigenobu; Shiino, Masataka

doi:10.1677/joe.0.1570245

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…Age-and sex-related differences exist in episodic GH secretion with changes in growth rate becoming evident between male and female rats at 25-30 days of age, but no correlation is evident between GH blood concentrations and rate of body weight gain after the onset of puberty (48,49). It is known that thyroid hormone is an important regulator of GH production by rat somatotrophs by inducing transcription of the GH gene (50,51). Hypophysectomy of immature rats arrests growth, as was seen in hypophysectomized calves in the present study, but the persistence of GH-immunoreactivity in the brains (amygdala and hypothalamus) of hypophysectomized rats and chickens suggests that GH synthesis does occur in the CNS (51)(52)(53).…”

Section: Discussionmentioning

confidence: 99%

“…It is known that thyroid hormone is an important regulator of GH production by rat somatotrophs by inducing transcription of the GH gene (50,51). Hypophysectomy of immature rats arrests growth, as was seen in hypophysectomized calves in the present study, but the persistence of GH-immunoreactivity in the brains (amygdala and hypothalamus) of hypophysectomized rats and chickens suggests that GH synthesis does occur in the CNS (51)(52)(53). Brain GH concentrations increase in rats when pituitary GH concentrations decrease (54,55), but circulating blood levels of GH in hypophysectomized rats and calves are extremely low to undetectable.…”

Section: Discussionmentioning

confidence: 99%

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Long-Term Growth after Hypophyseal Stalk Transection and Hypophysectomy of Beef Calves

Anderson

1999

Endocrinology

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Hypothalamic hormones regulate episodic and basal secretion of hormones from the anterior pituitary gland that affect metabolism and growth in cattle. This study focused on long-term growth in young calves subjected to hypophysectomy (HYPOX), hypophyseal stalk transection (HST), and sham operation control (SOC). Cross-bred (Hereford x Aberdeen Angus) and Hereford, and Aberdeen Angus calves were HYPOX (n ϭ 5), HST (n ϭ 5), or SOC (n ϭ 8) at 146 Ϯ 2 days of age, whereas another group was HST (n ϭ 5) or SOC (n ϭ 7) at 273 Ϯ 5 days of age. Body weight was determined every 21 days from birth to 1008 days of age. Anterior vena cava blood was withdrawn at 4-day intervals from day 64 -360 for RIA of GH, TSH, T 4 , T 3 , and LH, and at 20-min intervals for 480 min to determine episodic hormone secretion. Daily feed intake was determined in HST and SOC calves during an 80-day period. Birth weight averaged 35 Ϯ 1 kg (Ϯ SE) and was 142 Ϯ 4 kg at 126 days and 208 Ϯ 8 kg at 252 days before surgery. From day 146-1008, growth was arrested (P Ͻ 0.001) in HYPOX (0.06 Ϯ 0.01 kg/day) compared with SOC (0.50 Ϯ 0.04 kg/day) calves. Growth continued but at a significantly lower rate (P Ͻ 0.05) in calves HST at 146 days (0.32 Ϯ 0.07 kg/day) and 273 days (0.32 Ϯ 0.06 kg/day) compared with SOC (0.50 Ϯ 0.09 kg/day). Growth continued to be impaired to 1008 days, but more so in those HST at 146 days (432 Ϯ 43 kg BW) than 273 days (472 Ϯ 5 kg BW) and less (P Ͻ 0.05) than SOC (586 Ϯ 37 kg BW). Daily feed intake was consistently less (P Ͻ 0.05) in HST compared with SOC calves. Although episodic GH secretion was abolished and peripheral serum GH concentration remained consistently lower in HST (2.4 ng/ml) than SOC (5.5 ng/ml; P Ͻ 0.01), the calves continued to grow throughout 1008 days. Peripheral serum TSH concentration was less (P Ͻ 0.05) HST compared with SOC calves. There was an abrupt decrease (P Ͻ 0.001) in serum T 4 (4-fold) and T 3 (3-fold) concentration after surgery that remained to 360 days in HST compared with SOC calves. At the time calves were killed, pituitary gland weight was markedly reduced (P Ͻ 0.001) in HST (0.18 Ϯ 0.01 g/100 kg BW) compared with SOC (0.54 Ϯ 0.03 g/100 kg BW). Histological examination of pituitary glands from HST calves indicated the persistence of secretory GH and TSH cells in the same areas of the adenohypophysis as SOC calves. Coronal sections of the gland stained with performic acid-Alcian blue-periodic acid-Schiff-orange G, revealed GH and TSH secreting cells in HST calves similar to controls. These results indicate that long-term growth continues, but at a slower rate, after hypophyseal stalk transection of immature calves in spite of complete abolition of episodic GH secretion and consistently decreased basal secretion of GH, TSH, T 4 , and T 3 compared with sham-operated animals. Growth was abolished after hypophysectomy of immature calves in which circulating GH and TSH was undetectable. (Endocrinology 140: [2405][2406][2407][2408][2409][2410][2411][2412][2413][2414] 1999)

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Long-Term Growth after Hypophyseal Stalk Transection and Hypophysectomy of Beef Calves

Anderson

1999

Endocrinology

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“…The caudal hypophyseal arteries consist of extensions of rostral and caudal retia on the dorsal and caudal surfaces of the gland. It is known that thyroid hormone is an important regulator of GH production by rat somatotrophs by inducing transcription of the GH gene (50,51). Two or three hypophyseal arteries arise from the arterial circle of the cerebrum (44).…”

Section: Discussionmentioning

confidence: 99%

Long-Term Growth after Hypophyseal Stalk Transection and Hypophysectomy of Beef Calves*

et al. 1999

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Hypothalamic hormones regulate episodic and basal secretion of hormones from the anterior pituitary gland that affect metabolism and growth in cattle. This study focused on long-term growth in young calves subjected to hypophysectomy (HYPOX), hypophyseal stalk transection (HST), and sham operation control (SOC). Cross-bred (Hereford x Aberdeen Angus) and Hereford, and Aberdeen Angus calves were HYPOX (n = 5), HST (n = 5), or SOC (n = 8) at 146 +/- 2 days of age, whereas another group was HST (n = 5) or SOC (n = 7) at 273 +/- 5 days of age. Body weight was determined every 21 days from birth to 1008 days of age. Anterior vena cava blood was withdrawn at 4-day intervals from day 64-360 for RIA of GH, TSH, T4, T3, and LH, and at 20-min intervals for 480 min to determine episodic hormone secretion. Daily feed intake was determined in HST and SOC calves during an 80-day period. Birth weight averaged 35 +/- 1 kg (+/- SE) and was 142 +/- 4 kg at 126 days and 208 +/- 8 kg at 252 days before surgery. From day 146-1008, growth was arrested (P < 0.001) in HYPOX (0.06 +/- 0.01 kg/day) compared with SOC (0.50 +/- 0.04 kg/day) calves. Growth continued but at a significantly lower rate (P < 0.05) in calves HST at 146 days (0.32 +/- 0.07 kg/day) and 273 days (0.32 +/- 0.06 kg/day) compared with SOC (0.50 +/- 0.09 kg/day). Growth continued to be impaired to 1008 days, but more so in those HST at 146 days (432 +/- 43 kg BW) than 273 days (472 +/- 5 kg BW) and less (P < 0.05) than SOC (586 +/- 37 kg BW). Daily feed intake was consistently less (P < 0.05) in HST compared with SOC calves. Although episodic GH secretion was abolished and peripheral serum GH concentration remained consistently lower in HST (2.4 ng/ml) than SOC (5.5 ng/ml; P < 0.01), the calves continued to grow throughout 1008 days. Peripheral serum TSH concentration was less (P < 0.05) HST compared with SOC calves. There was an abrupt decrease (P < 0.001) in serum T4 (4-fold) and T3 (3-fold) concentration after surgery that remained to 360 days in HST compared with SOC calves. At the time calves were killed, pituitary gland weight was markedly reduced (P < 0.001) in HST (0.18 +/- 0.01 g/100 kg BW) compared with SOC (0.54 +/- 0.03 g/100 kg BW). Histological examination of pituitary glands from HST calves indicated the persistence of secretory GH and TSH cells in the same areas of the adenohypophysis as SOC calves. Coronal sections of the gland stained with performic acid-Alcian blue-periodic acid-Schiff-orange G, revealed GH and TSH secreting cells in HST calves similar to controls. These results indicate that long-term growth continues, but at a slower rate, after hypophyseal stalk transection of immature calves in spite of complete abolition of episodic GH secretion and consistently decreased basal secretion of GH, TSH, T4, and T3 compared with sham-operated animals. Growth was abolished after hypophysectomy of immature calves in which circulating GH and TSH was undetectable.

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The Influence of Thyroid Hormone on Growth Hormone Secretion and Action

Leung

Brent

2016

Growth Hormone Deficiency

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Effect of neonatal thyroidectomy on growth hormone secretion in the rat

Cited by 3 publications

References 21 publications

Long-Term Growth after Hypophyseal Stalk Transection and Hypophysectomy of Beef Calves

Long-Term Growth after Hypophyseal Stalk Transection and Hypophysectomy of Beef Calves

Long-Term Growth after Hypophyseal Stalk Transection and Hypophysectomy of Beef Calves*

The Influence of Thyroid Hormone on Growth Hormone Secretion and Action

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