Hormones
Hormones: Complex molecules produced by the body which act as chemical messengers to the body's cells. They are made by the endocrine glands of various organs, including the pituitary gland, parthyroid gland, thyroid gland, pancreas, hypothalamus, adrenal glands, stomach, small intestine, and gonads (males). These proteins, in response to the proper signal, are secreted and then exert influence on they are carried through the bloodstream to exert influence of target tissues, which may be a great distance away. They act by chemically stimulating a cell to increase or decrease its functional activity or to increase or decrease the secretion of another hormone.
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Sleep, Appetite, and Obesity: What Is the Link?
There is a well-documented relationship between short sleep duration and high body mass index (BMI). In the largest study, a survey on sleep duration and frequency of insomnia in more than 1.1 million participants, increasing BMI occurred for habitual sleep amounts below 7–8 hours [1]. A recent prospective study found an association between sleep curtailment and future weight gain [2]. The mechanism linking short sleep with weight gain is unknown, but Mignot and colleagues' study in this month's PLoS Medicine [3] adds to the growing evidence implicating leptin and ghrelin, the two key opposing hormones involved in appetite regulation.
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The Effect of Ingested Macronutrients on Post-Meal (Postprandial) Ghrelin Response: A Critical Review
Ghrelin is a powerful orexigenic gut hormone with growth hormone releasing activity. It plays a pivotal role for long-term energy balance and short-term food intake. It is also recognized as a potent signal for meal initiation. Ghrelin levels rise sharply before feeding onset, and are strongly suppressed by food ingestion. Postprandial ghrelin response is totally macronutrient specific in normal weight subjects, but is rather independent of macronutrient composition in obese. In rodents and lean individuals, isoenergetic meals of different macronutrient content suppress ghrelin to a variable extent. Carbohydrate appears to be the most effective macronutrient for ghrelin suppression, because of its rapid absorption and insulin-secreting effect. Protein induces prolonged ghrelin suppression and is considered to be the most satiating macronutrient. Fat, on the other hand, exhibits rather weak and insufficient ghrelin-suppressing capacity. The principal mediators involved in meal-induced ghrelin regulation are glucose, insulin, gastrointestinal hormones released in the postabsorptive phase, vagal activity, gastric emptying rate, and postprandial alterations in intestinal osmolarity.
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Selye's General Adaptation Syndrome
When Hans Selye was experimenting on rats by inflicting stress them either by injecting them with hormones or chemicals, making surgical incisions or exposing them to extreme temperatures, he noticed that the rats were all displaying the same group of symptoms. At first he believed that he had discovered a new hormone1; however, several years of further testing by injecting the rats with other substances, such as formaldehyde, revealed the same results. Even exposure to cold, cutting their spinal cords and forced exercise produced the same effects. The effects occurred in a predictable sequence that is now known as the General Adaptation Syndrome2 (GAS).
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Athletes are Not the Predominant AAS Users
Rule violations among elite-level sports competitors and tragedies among adolescents have largely defined the issue of non-medical anabolic-androgenic steroid (NMAAS) use for the public and policy makers. However, the predominant and oft-ignored segment of the NMAAS community exists in the general population that is neither participating in competitive sports nor adolescent. A clearer profile of NMAAS users within the general population is an initial step in developing a full understanding of NMAAS use and devising appropriate policy and interventions. This survey sought to provide a more comprehensive profile of NMAAS users by accessing a large sample of user respondents from around the United States.
Continue Reading » Athletes are Not the Predominant AAS Users
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