Afferent input from rat slow skeletal muscle inhibits  bioassayable growth hormone release

Gosselink, K. L.; Grindeland, R. E.; Roy, Roland R.; Zhong, Hui; Bigbee, A. J.; Edgerton, V. Reggie

doi:10.1152/jappl.2000.88.1.142

Cited by 17 publications

(32 citation statements)

References 28 publications

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“…A more likely cause is muscle proprioception, which promotes GH release more than lactate (20,21). Eccentric FERG actions may increase proprioception to yield a delayed, yet greater, GH release 30 minutes postexercise (21). Because the current study did not measure proprioception, this mechanism is speculative but deserves inquiry.…”

Section: Discussionmentioning

confidence: 86%

“…Performance of both concentric and eccentric actions within a single workout, as done with the current CE3 protocol but not in prior acute studies (14,28,29), may impede GH release, though this is unproven. A more likely cause is muscle proprioception, which promotes GH release more than lactate (20,21). Eccentric FERG actions may increase proprioception to yield a delayed, yet greater, GH release 30 minutes postexercise (21).…”

Section: Discussionmentioning

confidence: 99%

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Blood Lactate and Hormonal Responses to Prototype Flywheel Ergometer Workouts

Caruso

Coday²,

Monda³

et al. 2010

Journal of Strength and Conditioning Research

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The purpose of the study was to compare blood lactate and hormonal responses with flywheel ergometer (FERG) leg presses for preliminary assessment of workouts best suited for future in-flight resistance exercise. Comprised of 10 repetition sets, the workouts entailed 3 sets of concentric and eccentric (CE3) actions, or concentric-only actions done for 3 (CO3) or 6 (CO6) sets. Methods employed included assessment of blood lactate concentrations ([BLa-]) before and 5 minutes postexercise. Venous blood was also collected before and at 1 and 30 minutes postexercise to assess growth hormone, testosterone, cortisol concentrations ([GH], [T], [C]) and [T/C] ratios. [BLa-] were compared with 2 (time) x 3 (workout) analysis of variance. Hormones were assessed with 2 (gender) x 3 (time) x 3 (workout) analysis of covariances. Results showed [BLa-] had a time effect. Growth hormone concentration showed gender x workout, gender x time, and workout x time interactions, whereas [T] had a 3-way interaction. [C] had gender, time, and workout effects. [T/C] yielded a gender x time interaction. It was concluded that, because CO6 and CE3 yielded similar anabolic hormonal data but the latter had a lower [C] 30 minutes postexercise, CE3 served as the best workout. Although the FERG was originally designed for microgravity, the effort put forth by current subjects was like that for workouts aimed at greater athletic performance and conditioning. Practical applications suggest that eccentric actions should be used for FERG workouts geared toward muscle mass and strength improvement.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Blood Lactate and Hormonal Responses to Prototype Flywheel Ergometer Workouts

Caruso

Coday²,

Monda³

et al. 2010

Journal of Strength and Conditioning Research

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“…When rats are subjected to metabolic challenges such as fasting or cold exposure, GH measured by immunoassay (IGH) is unchanged, whereas pituitary GH measured by tibial bioassay (BGH) decreases (6). Previous experiments in our and other laboratories have shown that BGH is a pituitaryderived, biologically active peptide, which exists in humans (10,18,19,20, unpublished observations), rats (5,6,12,13), cattle (7), and cats (unpublished observations).…”

mentioning

confidence: 73%

“…Whereas BGH is known to respond to metabolic perturbations (6), recent data indicate that stimulation of proprioceptive neuromuscular afferents may be an additional pathway through which BGH is regulated. Gosselink et al (12,13) recently showed rapid BGH release from the rat pituitary in response to a short bout of electrical stimulation (15 min or less) of lowthreshold axons of the promixal ends of severed tibial and peroneal nerves, which innervate predominantly fast muscles. Neither muscle-derived nor other metabolic factors appeared to be involved in facilitating BGH release under these conditions, because stimulating the distal ends of these cut nerves for the same amount of time had no effect on plasma or pituitary BGH concentrations (13).…”

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confidence: 99%

Bioassayable growth hormone release in rats in response to a single bout of treadmill exercise

Bigbee

Gosselink²,

Roy

et al. 2000

Journal of Applied Physiology

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Plasma growth hormone (GH) measured by immunoassay [immunoassayable GH (IGH)] and by tibial bioassay [bioassayable GH (BGH)] increases in humans in response to exercise. In rats, however, IGH does not change in response to exercise. The objective of this study was to determine the BGH response to an acute exercise bout in rats. The rats ran on a treadmill at a rate of 27 m/min for 15 min, after which plasma and pituitary hormones, including IGH and BGH, and plasma metabolites were measured. Plasma and pituitary IGH were unchanged from control groups after the acute exercise bout, whereas plasma BGH was increased by 300% and pituitary BGH was decreased by 50%. Plasma thyroxine and corticosterone levels were significantly increased after a single exercise bout, but plasma testosterone, 3,5, 3'-triiodothyronine, glucose, lactate, and triglyceride concentrations were unchanged. Given previous results from in situ nerve stimulation studies (Gosselink KL, Grindeland RE, Roy RR, Zhong H, Bigbee AJ, Grossman EJ, and Edgerton VR. J Appl Physiol 84: 1425-1430, 1998), these in vivo results are consistent with the rapid BGH response during exercise being induced by the activation of muscle afferents.

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“…Repeated cycling trials with 1 h recovery in between produced similar lactate responses, but attenuated GH response in the second trial, leading the authors to conclude that proprioceptive feedback was a greater contributor to GH secretion than lactate (Stokes et al 2002). Gosselink et al (2000) documented GH responses through proprioceptive feedback through muscle spindles and Golgi tendon organs. Thus, proprioceptive feedback of a greater magnitude to relative loading versus absolute loading of ECC contractions may have contributed to the similar GH responses in the present study.…”

Section: Discussionmentioning

confidence: 99%

Similar hormonal responses to concentric and eccentric muscle actions using relative loading

et al. 2005

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Conventional resistance exercise is performed using sequential concentric (CON) and eccentric (ECC) contractions, utilizing the same muscle load. Thus, relative to maximal CON and ECC resistance, the ECC contraction is loaded to a lesser degree. We have recently shown that at the same absolute load, CON contractions are associated with greater growth hormone (GH) but similar total testosterone (TT) and free testosterone (FT) responses compared with ECC contractions and attributed the larger GH response to greater relative CON loading. In the present study, we have examined the same endocrine parameters to six different upper and lower body exercises using relative loading rather than absolute loading, hypothesizing that GH responses would be similar for CON and ECC actions, but TT and FT responses would be greater after ECC contractions. Seven young men with recreational weight training experience completed an ECC and CON muscle contraction trial on two different occasions in a counterbalanced fashion. The exercises consisted of four sets of 10 repetitions of lat pull-down, leg press, bench press, leg extension, military press, and leg curl exercises at 65% of an ECC or CON 1-RM with 90 s between sets and exercises. CON and ECC actions were performed at the same speed. ECC 1-RMs were considered to be 120% of the CON 1-RM for the same exercise. Blood samples were collected before, immediately after, and 15 min after the exercise. GH significantly increased across both trials but was not different between the two trials. Total testosterone was not significantly altered in response to either trial; however, free testosterone concentrations increased in response to both ECC and CON trials. Data suggest that CON and ECC muscle contractions produce similar GH, T, and free testosterone responses with the same relative loading.

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Afferent input from rat slow skeletal muscle inhibits bioassayable growth hormone release

Cited by 17 publications

References 28 publications

Blood Lactate and Hormonal Responses to Prototype Flywheel Ergometer Workouts

Blood Lactate and Hormonal Responses to Prototype Flywheel Ergometer Workouts

Bioassayable growth hormone release in rats in response to a single bout of treadmill exercise

Similar hormonal responses to concentric and eccentric muscle actions using relative loading

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