Hungry

Eat to live not live to eat

Human growth hormone is secreted almost exclusively at night during sleep---figure it out.

So it is not released due to exercise then? Or before you eat due to ghrelin as you were discussing above?

Yes---but, as you can see, the greatest amount is secreted during sleep.

Yes, exercise does stimulate its production but:

"Somatotropic cells in the anterior pituitary gland then synthesize and secrete GH in a pulsatile manner, in response to these stimuli by the hypothalamus. The largest and most predictable of these GH peaks occurs about an hour after onset of sleep with plasma levels of 13 to 72 ng/mL.[10] Otherwise there is wide variation between days and individuals. Nearly fifty percent of GH secretion occurs during the third and fourth NREM sleep stages.[11] Surges of secretion during the day occur at 3- to 5-hour intervals.[2] The plasma concentration of GH during these peaks may range from 5 to even 45 ng/mL.[12] Between the peaks, basal GH levels are low, usually less than 5 ng/mL for most of the day and night.[10] Additional analysis of the pulsatile profile of GH described in all cases less than 1 ng/ml for basal levels while maximum peaks were situated around 10-20 ng/mL.[13][14]

A number of factors are known to affect GH secretion, such as age, gender, diet, exercise, stress, AND OTHER HORMONES.[2] Young adolescents secrete GH at the rate of about 700 μg/day, while healthy adults secrete GH at the rate of about 400 μg/day.[15]



"...and other hormones." (emphasis mine)

So, it is not almost exclusively at night as you quoted. Also, how does insulin play into this? Why are you stressing 'other hormones' out of interest?

The majority of it, in most people, (particularly children) is released at night, during sleep. I stressed "other hormones" because there are a number of hormones that affect its release--ghrelin is just one of them. Insulin suppresses HGH.

p.s. Going to bed so I can get my HGH.

from what I know, growth hormone is almost zero during the day and maximizes during sleep stage 3. The quality of your sleep is much more important than the quantity.

Circadian modulation of hepatic transcriptome in transgenic rats expressing human growth hormone.
Hirao J, Niino N, Arakawa S, Shibata S, Mori K, Ando Y, Furukawa T, Sanbuissho A, Manabe S, Mori Y, Nishihara M.
Source
Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., Fukuroi, Shizuoka, Japan. hirao.jun.hw@daiichisankyo.co.jp
Abstract
The secretory profile of growth hormone (GH) is sexually dimorphic in rats. In male transgenic (TG) rats expressing human GH (hGH) that we generated, the circulating levels of both hGH and endogenous GH are flattened with no male-type pulsatility. To elucidate the regulatory role of episodic GH profile on the liver, the hepatic transcriptome of male TG rats at the middle of the light and dark phases was characterized by genome-wide analyses as compared with that of male wild-type (WT) rats. Transcripts commonly up- or down-regulated regardless of the lighting conditions in TG rats were mainly enriched in the metabolism of xenobiotics. In TG rats, the gene expression profile was functionally feminized, verifying that the sexually dimorphic profile of GH rather than genetic sexuality is a stronger sex-determining factor on the hepatic transcriptome. The common transcripts which fluctuated during the day in both TG and WT rats were enriched in circadian rhythm signaling, and physiological rhythmicity was considered to be finely interconnected with liver metabolism via sexually dimorphic GH secretion. In contrast, some genes were differentially regulated in TG rats at only one of two time points measured, and others were fluctuated daily in only one genotype. In particular, some genes involved in the GH signaling pathway were included, suggesting the signal transduction is circadian-modulated depending upon the GH profile. Our transcriptome analyses clarified the regulatory role of episodic GH profile on the liver and strengthen the functional link between sexually dimorphic GH secretion, liver metabolism, and its circadian regulation.
PMID: 20930462 [PubMed - indexed for MEDLINE] Free full text

Growth Horm IGF Res. 2010 Oct;20(5):380-5. doi: 10.1016/j.ghir.2010.08.001. Epub 2010 Aug 30.
Effect of high- and low-intensity exercise and metabolic acidosis on levels of GH, IGF-I, IGFBP-3 and cortisol.
Wahl P, Zinner C, Achtzehn S, Bloch W, Mester J.
Source
Institute of Training Science and Sport Informatics, German Sport University, Cologne, Germany. Wahl@dshs-koeln.de
Abstract
OBJECTIVE:
The purpose of the present study was to examine the acute hormonal response of a short term high-intensity training (HIT) versus a high volume endurance training (HVT) and to determine the contribution of the metabolic acidosis as a stimulus for possibly different reactions of circulating hGH, IGF-1, IGFBP-3 and cortisol.
DESIGN:
Eleven subjects participated in three experimental trials separated by one week. Two times subjects performed four 30s maximal effort exercise bouts on a cycle ergometer separated by 5 min rest each. Before the exercise subjects either received (single-blinded) bicarbonate (HIT (B)) or a placebo (HIT (P)). The third exercise trail consisted of a constant load exercise for 1h at 50% VO₂max (HVT). Venous blood samples were taken under resting conditions, 10 min, 60 min and 240 min after each exercise condition to determine hGH, IGF-1, IGFBP-3 and cortisol serum concentrations. Capillary blood samples were taken to determine lactate concentrations and blood gas parameters.
RESULTS:
Power output, mean lactate concentrations and mean pH values were significantly higher during HIT (B) compared to HIT (P). Serum cortisol and hGH concentrations were significantly increased 10 min post exercise in both HIT interventions. IGFBP-3 was only significantly increased after HIT (P), whereas IGF-1 was not affected by any of the interventions. HVT showed no significant effects on cortisol, hGH, IGF-1 and IGFBP-3 levels. Additionally it was shown that the diminished acidosis during HIT (B) attenuates the cortisol and hGH response.
CONCLUSIONS:
The present study suggests that HIT/acidosis is a stimulus for exercise-induced cortisol/hGH secretion, but not for IGF-1 and IGFBP-3 under these experimental conditions. These findings might be relevant for arrangements of interval training, due to the fact that active or passive recovery during rest periods influence the acid base status and may therefore influence the hormonal response.

Whatever, when I lab ratted it did not release during the day , only at night until early AM when cortisol started kicking.

Sara!!!!!
1. I'm not a football player.
2. ummm, don't even know where to begin.....

Love you, and sharing what knowledge I do have with you, so let's discuss this another day in messages. I'd rather have people think, than tell them what to think.