Influence of oral contraceptive use on growth hormone in vivo bioactivity following resistance exercise: Responses of molecular mass variants

Kraemer, William J.; Nindl, Bradley C.; Volek, Jeff S.; Marx, James O.; Gotshalk, Lincoln A.; Bush, Jill A.; Welsch, Jill R.; Vingren, Jakob L.; Spiering, Barry A.; Fragala, Maren S.; Hatfield, Disa L.; Ho, Jen Yu; Maresh, Carl M.; Mastro, Andrea M.; Hymer, Wesley C.

doi:10.1016/j.ghir.2007.10.001

Cited by 11 publications

(7 citation statements)

References 29 publications

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“…Previous work from our laboratories has shown that an acute exercise bout in young women seems to elicit an increase in iGH, but not bGH, while chronic RE training increases bGH (23,32,33). On the basis of these results, we speculated that chronic RE increased the release of a spectrum of GH molecules that were necessary for full expression of the somatogenic and metabolic actions usually attributed to GH.…”

Section: Discussionmentioning

confidence: 66%

“…Concentrations of bGH in plasma samples were determined by the method of Greenspan and Li (18) exactly as reported by our group in several recent studies (22,23,(31)(32)(33)(34)(35). Female SpragueDawley rats (Hilltop Labs, Scottsdale, PA), hypophysectomized at 26 -28 days of age, were used 2 wk after surgery.…”

Section: Methodsmentioning

confidence: 99%

“…Chronic exercise has demonstrated bGH effects in women and in male astronauts (23,32,33,37,38). Studies have also reported that iGH is blunted in response to cardiovascular exercise in obese individuals, but further research on group differences in response to RE is needed.…”

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confidence: 99%

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Immunoreactive and bioactive growth hormone responses to resistance exercise in men who are lean or obese

Thomas

Kraemer

Kennett

et al. 2011

Journal of Applied Physiology

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The present study was designed to examine the effects of a highvolume, whole body acute resistance exercise (RE) protocol on immunoreactive GH (iGH), bioactive GH (bGH), and GH-binding protein (GHBP) in sedentary lean and obese men. Nine obese (mean Ϯ SD: 20.8 Ϯ 2.1 yr old, 177.0 Ϯ 4.1 cm height, 108.7 Ϯ 15.9 kg body mass, 37.6 Ϯ 5.29% body fat) and nine lean (20.1 Ϯ 2.1 yr old, 177.8 Ϯ 8.7 cm height, 71.7 Ϯ 5.8 kg body mass, 14.7 Ϯ 3.54% body fat) men completed an acute RE protocol (6 exercises, 3 sets of 10 repetitions at 85-95% of 10 repetitions maximum with 120-and 90-s rest periods), and blood samples were collected before, at the midpoint, and immediately after exercise and during recovery (ϩ50, ϩ70, and ϩ110). In contrast to prior studies, which examined acute responses to cardiovascular exercise protocols, groups did not differ in iGH response to the exercise stimulus. However, bGH concentrations overall were significantly lower in the obese than the lean participants (P Ͻ 0.001). Additionally, obese individuals had significantly higher GHBP concentrations (P Ͻ 0.001). Results suggest that obese and lean sedentary men performing a high-volume, whole body acute RE protocol demonstrate similar increases in iGH. Blunted bGH and elevated GHBP concentrations are indicative of altered GH activity associated with obesity. Prior research findings of blunted iGH response may be attributable to RE protocols not equated on relative intensity or volume. These results underscore the complexity of pituitary biology and its related mechanisms and may have implications for exercise prescription in the treatment of obesity.

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Section: Discussionmentioning

confidence: 66%

Section: Methodsmentioning

confidence: 99%

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Immunoreactive and bioactive growth hormone responses to resistance exercise in men who are lean or obese

Thomas

Kraemer

Kennett

et al. 2011

Journal of Applied Physiology

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“…Further, the pituitary somatotroph network can produce large pulses of GH in response to physiological needs (up to 1000-fold increases), which are related to differences in gender, body size, metabolism, and sex steroids [34]. Circulating estradiol concentrations are associated with higher GH concentrations and this may play a role in our understanding of the sexual dimorphism that exists in GH concentrations [35,36]. In rats, androgen and estrogen receptors are found on somatostatin and GHRH neurons [13,37] and when ovariectomised, estrogen replacement produces significant increases in GHRH-R mRNA expression and GH concentrations [38].…”

Section: Discussionmentioning

confidence: 99%

Acute resistance exercise stimulates sex-specific dimeric immunoreactive growth hormone responses

Luk

Kraemer

Szivak

et al. 2015

Growth Hormone & IGF Research

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“…All GH isoforms increased after exercise in both, strong and weak untrained women, although the lower molecular weight variants were less responsive to greater amounts of exercise in stronger women [ 45 ]. The use of oral contraceptive (OC) in untrained women also seemed to influence the GH response during exercise when assessed by these assay methods, with higher abundance of high molecular weight GH in both resting and post exercise states in the OC group [ 46 ]. In contrast, other studies only confirmed that in the basal state all GH isoforms tend to be higher in females, but the 20 K–22 K-GH ratio was not different between sexes.…”

Section: Gh Isoform Secretion In Healthy and Diseasementioning

confidence: 99%

Growth hormone: isoforms, clinical aspects and assays interference

Schweizer

Ribeiro‐Oliveira

Bidlingmaier

2018

Clin Diabetes Endocrinol

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The measurement of circulating concentrations of growth hormone (GH) is an indispensable tool in the diagnosis of both GH deficiency and GH excess. GH is a heterogeneous protein composed of several molecular isoforms, but the physiological role of these different isoforms has not yet been fully understood. The 22KD GH (22 K-GH) is the main isoform in circulation, followed by 20KD GH (20 K-GH) and other rare isoforms. Studies have been performed to better understand the biological actions of the different isoforms as well as their importance in pathological conditions. Generally, the non-22 K- and 20 K-GH isoforms are secreted in parallel to 22 K-GH, and only very moderate changes in the ratio between isoforms have been described in some pituitary tumors or during exercise. Therefore, in a diagnostic approach, concentrations of 22 K-GH accurately reflect total GH secretion. On the other hand, the differential recognition of GH isoforms by different GH immunoassays used in clinical routine contributes to the known discrepancy in results from different GH assays. This makes the application of uniform decision limits problematic. Therefore, the worldwide efforts to standardize GH assays include the recommendation to use 22 K-GH specific GH assays calibrated against the pure 22 K-GH reference preparation 98/574. Adoption of this recommendation might lead to improvement in diagnosis and follow-up of pathological conditions, and facilitate the comparison of results from different laboratories.

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Influence of oral contraceptive use on growth hormone in vivo bioactivity following resistance exercise: Responses of molecular mass variants

Cited by 11 publications

References 29 publications

Immunoreactive and bioactive growth hormone responses to resistance exercise in men who are lean or obese

Immunoreactive and bioactive growth hormone responses to resistance exercise in men who are lean or obese

Acute resistance exercise stimulates sex-specific dimeric immunoreactive growth hormone responses

Growth hormone: isoforms, clinical aspects and assays interference

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