Dr. Squat - Dr. Fred Hatfield

From Medline
"
Resource: MEDLINE
Title: From growth hormone-releasing peptides to ghrelin: discovery of new modulators of GH secretion.
Author: Lengyel AM
Citation: Arquivos Brasileiros de Endocrinologia e Metabologia 50(1):17-24, 2006 Feb
50(1):17-24, 2006 Feb
Year: 2006
Abstract: Growth hormone (GH)-releasing hormone and somatostatin modulate GH secretion. A third mechanism has been discovered in the last decade, involving the action of GH secretagogues. Ghrelin is a new acylated peptide produced mainly by the stomach, but also synthesized in the hypothalamus. This compound increases both GH release and food intake. The relative roles of hypothalamic and circulating ghrelin on GH secretion are still unknown. Endogenous ghrelin might amplify the basic pattern of GH secretion, optimizing somatotroph responsiveness to GH-releasing hormone. This peptide activates multiple interdependent intracellular pathways at the somatotroph, involving protein kinase C, protein kinase A and extracellular calcium systems. However, as ghrelin induces a greater release of GH in vivo, its main site of action is the hypothalamus. In this paper we review the available data on the discovery of ghrelin, the mechanisms of action and possible physiological roles of GH secretagogues and ghrelin on GH secretion, and, finally, the regulation of GH release in man after intravenous administration of these peptides."
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Apparently the full text is available but i have yet to actually get a hold of it. This seems to be an interesting one for us... i'll keep looking...

" Resource: MEDLINE
Title: Nocturnal ghrelin, ACTH, GH and cortisol secretion after sleep deprivation in humans.
Author: Schussler P
Add.Author / Editor: Uhr M
Ising M
Weikel JC
Schmid DA
Held K
Mathias S
Steiger A
Citation: Psychoneuroendocrinology 31(:915-23, 2006 Sep
31(:915-23, 2006 Sep
Year: 2006
Abstract: Ghrelin is an endogenous ligand of the growth hormone (GH) secretagogue (GHS) receptor. It is hypothesised to play a key role in energy balance stimulating food intake and body weight. Besides GH-releasing hormone (GHRH) and somatostatin, it is thought to be a regulating factor of GH release. Ghrelin also appears to be involved in sleep regulation. We showed recently that ghrelin promotes slow-wave sleep and the nocturnal release of GH, cortisol and prolactin in humans. Similarly, promotion of non-rapid-eye-movement (NREM) sleep was reported in mice after systemic ghrelin. If ghrelin is a factor that induces and/or maintains sleep, it should be enhanced after a period of sleep deprivation (SD). To clarify this issue, nocturnal ghrelin, GH, ACTH and cortisol plasma concentrations were determined and simultaneously sleep electroencephalogram (EEG) was recorded (2300-0700 h) during sleep before and after 1 night of total SD in 8 healthy subjects. Compared to baseline, ghrelin levels increased earlier by a non-significant trend, already before the beginning of recovery sleep. Further a non-significant trend occurred, suggesting higher ghrelin secretion in the first half of the night. The ghrelin maximum was found significantly earlier after SD than at baseline. GH secretion during the first half of the night and total night after SD were elevated. ACTH and cortisol were also elevated,"

"Resource: MEDLINE
Title: Nocturnal ghrelin levels--relationship to sleep EEG, the levels of growth hormone, ACTH and cortisol--and gender differences.[erratum appears in J Sleep Res. 2006 Mar;15(1):107 Note: Weikel, Jotta [corrected to Weikel, Jutta]].
Author: Schuessler P
Add.Author / Editor: Uhr M
Ising M
Schmid D
Weikel J
Steiger A
Citation: Journal of Sleep Research 14(4):329-36, 2005 Dec
14(4):329-36, 2005 Dec
Year: 2005
Abstract: Ghrelin, an endogenous ligand of the growth hormone (GH) secretagogue receptor, stimulates sleep, appetite and weight gain as well as the secretion of GH, adrenocorticotropic hormone (ACTH), cortisol in humans and rodents. The interaction between nocturnal ghrelin levels, sleep EEG and the secretion of these hormones was not investigated systematically so far. Furthermore conflicting data exist on gender differences in nocturnal ghrelin secretion. We examined simultaneously sleep EEG and the nocturnal levels of ghrelin, GH, ACTH and cortisol in young and middle-aged normal human subjects (eight males, eight females). A significant interaction between gender and the course of ghrelin concentration was observed to the interval between 20:00 and 23:00 hours. In males a continuous increase of ghrelin levels before sleep onset was found. In females, however, a rise of ghrelin during the night was missed. We found a trend suggesting a lower time spent in stage I sleep in subjects with high nocturnal ghrelin levels. Other systematic interactions between plasma ghrelin, sleep EEG and other hormones were not found. No peak in plasma ghrelin levels resembling the GH surge was observed. We suggest that under naturalistic conditions plasma ghrelin levels show no distinct interaction with sleep."

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OK there is some food for thought... Im not sure what to make of ghrelin yet... let alone know what the hell i should *do* to make IT do stuff that i want

Wikipedia time perhaps..