A low dose euglycemic infusion of recombinant human insulin-like growth factor I rapidly suppresses fasting-enhanced pulsatile growth hormone secretion in humans.

Hartman, Mark L.; Clayton, Peter; Johnson, Michael L.; Celniker, Abbie; Perlman, Andrew J.; Alberti, K. G. M. M.; Thorner, Michael O.

doi:10.1172/jci116480

Cited by 179 publications

(73 citation statements)

References 51 publications

(78 reference statements)

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“…It has been demonstrated in humans that GH exerts its negative feedback effect by stimulating hypothalamic somatostatin secretion [50]. Additionally, the GH-induced elevated circulating IGF-1 levels also inhibit pituitary GH secretion [51].…”

Section: Discussionmentioning

confidence: 99%

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Beijerink

Bhatti

Okkens

et al. 2007

Domestic Animal Endocrinology

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The aim of this study was to investigate the effects of treatment with medroxyprogesterone acetate (MPA) on canine adenohypophyseal function. Five Beagle bitches were treated with MPA (10 mg/kg, every 4 weeks) and their adenohypophyseal function was assessed in a combined adenohypophyseal function test. Four hypophysiotropic hormones (CRH, GHRH, GnRH, and TRH) were administered before and 2, 5, 8, and 11 months after the start of MPA treatment, and blood samples for determination of the plasma concentrations of ACTH, cortisol, GH, IGF-1, LH, FSH, prolactin, ␣-MSH, and TSH were collected at −15, 0, 5, 10, 20, 30, and 45 min after suprapituitary stimulation.MPA successfully prevented the occurrence of estrus, ovulation, and a subsequent luteal phase. MPA treatment did not affect basal and GnRH-induced plasma LH concentrations. The basal plasma FSH concentration was significantly higher at 2 months after the start of MPA treatment than before or at 5, 8, and 11 months after the start of treatment. The maximal FSH increment and the AUC for N.J. Beijerink et al. / Domestic Animal Endocrinology xxx (2006) xxx-xxxmonths of MPA treatment. Differences in mean basal plasma GH concentrations before and during treatment were not significant, but MPA treatment resulted in significantly elevated basal plasma IGF-1 concentrations at 8 and 11 months. MPA treatment did not affect basal and stimulated plasma ACTH concentrations, with the exception of a decreased AUC for ACTH at 11 months. In contrast, the maximal cortisol increment and the AUC for cortisol after suprapituitary stimulation were significantly lower during MPA treatment than prior to treatment. MPA treatment did not affect basal plasma concentrations of prolactin, TSH, and ␣-MSH, with the exception of slightly increased basal plasma TSH concentrations at 8 months of treatment. MPA treatment did not affect TRH-induced plasma concentrations of prolactin and TSH.In conclusion, the effects of chronic MPA treatment on adenohypophyseal function included increased FSH secretion, unaffected LH secretion, activation of the mammary GH-induced IGF-I secretion, slightly activated TSH secretion, suppression of the hypothalamic-pituitary-adrenocortical axis, and unaffected secretion of prolactin and ␣-MSH.

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Section: Discussionmentioning

confidence: 99%

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Beijerink

Bhatti

Okkens

et al. 2007

Domestic Animal Endocrinology

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“…One possibility is a modulation of GH response by IGF-I. It is well known that IGF-I has an inhibitory action on pulsatile and provocation-induced GH secretions in humans (16,17). Since plasma IGF-I levels in the patients with vagotomy were lower than those in normal subjects, it may be responsible for the augmentation of GH response to ghrelin in vagotomized patients.…”

Section: Discussionmentioning

confidence: 99%

Intravenous administration of ghrelin stimulates growth hormone secretion in vagotomized patients as well as normal subjects

Takeno

Okimura

Iguchi³

et al. 2004

European Journal of Endocrinology

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Objective: Ghrelin is a potent peptide stimulating GH secretion. Besides its direct action on the pituitary, ghrelin has been reported to stimulate GH release via the vagal afferent nerve in rats. To examine the involvement of vagal nerve in ghrelin-induced GH secretion in humans, GH responses to ghrelin were compared between vagotomized patients with gastrectomy and normal subjects. Methods: Ghrelin (0.2 mg/kg) or GHRH (1 mg/kg) was administered intravenously in vagotomized patients and normal subjects on separate days, and plasma GH responses to the stimuli were examined. Results: Ghrelin caused a significant plasma GH rise in both vagotomized patients and normal subjects. Peak GH levels in vagotomized patients (37.5^16.9 ng/ml) were not different from those in normal subjects (29.9^23.1 ng/ml). The areas under the curve of GH response to ghrelin did not differ between the two groups. GHRH also increased GH levels, and peak GH levels and areas under the curve after GHRH stimulation were also comparable between vagotomized patients and normal subjects. Conclusions: In the present study, the involvement of the afferent vagal nerve in ghrelin-induced GH secretion was not confirmed in humans.European Journal of Endocrinology 151 447-450

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“…The results demonstrate that the plasma IGF-I levels were significantly higher in hypothyroidism than in euthyroidism. Elevated circulating levels of IGF-I have been reported to inhibit pulsatile pituitary GH secretion (Hartman et al 1993), mainly by attenuation of spontaneous GH pulse amplitude (Bermann et al 1994).…”

Section: Dogmentioning

confidence: 99%

“…This regulatory system is influenced by negative feedback from peripherally formed growth factors, particularly insulin-like growth factor-I (IGF-I) (Hartman et al 1993, Bermann et al 1994. In addition, a recently identified GH-releasing peptide, called Ghrelin, is likely to play a role in the regulation of pituitary GH secretion (Kojima et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Primary hypothyroidism in dogs is associated with elevated GH release

Diaz-Espineira²,

Mol³

et al. 2001

Journal of Endocrinology

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The pulsatile secretion patterns of GH were investigated in seven beagle bitches by collecting blood samples every 10 min for 6 h during euthyroidism and 1·5 years after induction of primary hypothyroidism. Hypothyroidism was induced by surgical removal of the thyroid gland and subsequent destruction of any remnant thyroid tissue by oral administration of sodium [131 I]iodide. Some of the physical changes observed in the dogs with primary hypothyroidism mimicked those of acromegaly. During both euthyroidism and hypothyroidism GH was secreted in a pulsatile fashion. The mean ( ...) basal plasma GH concentration was significantly higher (P=0·003) in the hypothyroid state (4·1 1·6 µg/l) than in the euthyroid state (1·2 0·4 µg/l). Likewise, the mean area under the curve (AUC) for GH above the zero-level during hypothyroidism (27·0 10·0 µg/l 6 h) was significantly higher (P=0·004) than that during euthyroidism (11·7 2·0 µg/l 6 h). The mean AUC for GH above the baseline was significantly lower (P=0·008) during hypothyroidism (2·4 0·8 µg/l 6 h) than during euthyroidism (4·5 1·8 µg/l 6 h), whereas there was no significant difference in GH pulse frequency. The mean plasma IGF-I level was significantly higher (P<0·01) in the hypothyroid state (169 45 µg/l) than in the euthyroid (97 15 µg/l). The results of this study demonstrate that primary hypothyroidism in dogs is associated with elevated basal GH secretion and less GH secreted in pulses. This elevated GH secretion has endocrine significance as illustrated by elevated plasma IGF-I levels and some physical changes mimicking acromegaly. It is discussed that the increased GH release in hypothyroid dogs may be the result of the absence of a response element for thyroid hormone within the canine pituitary GH gene and alterations in supra-pituitary regulation.

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A low dose euglycemic infusion of recombinant human insulin-like growth factor I rapidly suppresses fasting-enhanced pulsatile growth hormone secretion in humans.

Cited by 179 publications

References 51 publications

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Intravenous administration of ghrelin stimulates growth hormone secretion in vagotomized patients as well as normal subjects

Primary hypothyroidism in dogs is associated with elevated GH release

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