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15

A hormone is defined as "a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism" (I'm just taking Wikipedia definition). Hormones work by binding to specific receptors present on their target cells so, if there is something in the environment that mimics the hormone, by ...


11

Yes. Menopause is common for long-lived mammals. For instance, in the wild, killer whales go in a sort of menopause as reported in 2009 by Ward et al. Front Zool. 2009 Feb 3;6:4. So it is not due to captivity. According to a Nature review, reproductive cessation has also been documented in non-human primates, rodents, whales, dogs, rabbits, elephants and ...


10

Short answer: yes. Although clearly the infradian changes in steroid hormones in females are quite "obvious", other changes are less evident, but happen nonetheless in males as well as in females. Most of the hormones produced by endocrine organs such as the hypothalamus (a region at the base of the brain) or the hypophisis are not secreted in a continuous ...


10

Although male testes are responsible for huge testosterone secretion, testosterone can be produced by other organs both in males and females. So, women do have testosterone. Similarly, estrogen is also produced in men and not only in women. In addition, both sexes produce the androgen and the estrogen receptors, so endogeneous or external testosterone will ...


10

I'll point you to this article by A. Tuiten et al. To quickly answer your question, yes, testosterone does have an enhancing effect on the sexual behaviour of human healthy adult females. The (admittedly small) study indicated that after an dose of testosterone was given to the women there was found: a statistically significantly [sic] increase in ...


9

Fetal testis produces testosterone from cholesterol. There is a peak of production around 15 weeks of gestation (the "masculinization programming window"). So the genotype of the fetus can affect testosterone levels directly via effects on the biosynthesis of the hormone, or indirectly by defective regulation of the pathway's activity. However, exposure to ...


9

Some assumptions made in the question. There is an implicit assumption in your question which I don't think to be correct: you assume that any reaction of the human organism to stress (let's substitute "fright" by "stress" in your question) is a physiological reaction, meaning that this reaction somehow helps the organism to overcome the stressful ...


8

That book was likely crap, but in short the answer is yes, probably there is a genetic basis in the metabolism, with human 'types' that could benefit from a personalized nutrition. The discipline studying these relationship is called nutrigenomics, and the main concept is similar to what is being told for personalized medicine. The bad news is that ...


8

There is a good open access review about the effects of different hormones on sexual arousal. In most instances, the hormone is acting on the brain, which signals the information to gonads and genitals via nerves (i.e., the hypothalamic-pituitary-gonadal axis). However, in a study in which I have participated, we found a more direct and probably ancient ...


7

In short, because the easiest way to get the protein coding sequence of the gene is to create cDNA based on the mRNA, and insulin mRNA is only expressed in pancreatic cells. Insulin gene consists of two exons. That means, amplifying the genome will not give us a coding sequence -- two pieces of that sequence will be interrupted by a large, non-coding ...


6

I found this - Celec et al. (2003) Circatrigintan cycle of salivary testosterone in human male. Biological Rhythm Research 34: 305-315 Conclusion. We believe that this is the first study demonstrating the existence of circatrigintan and circavigintan rhythms of testosterone in human males. Our findings might have implications in human physiology ...


6

Well... I'm excited that my first contribution to this site will include a study of strippers! http://whywereason.wordpress.com/2011/06/29/menstruation-attraction-why-females-shouldnt-flirt-while-menstruating-and-why-bears-can-smell-the-menstruation/ I have read other, more detailed analysis of this (and similar) research that suggests strongly that our ...


6

From what I have gathered, I would think that humans do have receptors that are able to detect pheromones. For example, some studies that have indicated human responses to pheromones. Of these pheromone responses, some have been traced to the olfactory mucosa and olfactory epithelium. The trace amine-associated receptors (TAAR) for which humans have 7 ...


6

An hormone is not different from most other molecules. To have an effect on a cell it binds to a (more or less specific) receptor, located either on the plasma membrane or inside the cell, and it initiates an intracellular cascade of events1. There are several ways an hormone can have different effects: there can be multiple receptors for the same ...


6

In general the answer is yes. However, the degree in which this is true and the degree in which the human body can adjust and adapt to new food types is larger misjudged. I am of the opinion that metabolism is largely controlled by the microbiome. It is largely recognized that the gut biome does adjust depending on diet and will also vary depending on drug ...


6

Yes, something can be both a hormone and an enzyme. There are a group of hormones known as peptide hormones. These are proteins (such as enzymes) that act as hormones indirectly (and maybe directly too?). A hormone is a chemical secreted by a cell that has some effect on another cell elsewhere in the body. In this case, the chemical just happens to be an ...


4

The human/animal digestive tract breaks down food chemically (with low pH/acid), enzymatically (like proteases and glycolytic enaymes which break down protein and sugars respectively), as well as symbiotically (bacteria participates in the breakdown of some compounds in the gut). The results are released into the blood stream for the most of the body to ...


4

The real answer is probably more than you want, but its easy to do better than the list above. I took a look through GEO for human circadian expression data and surprisingly I only found 2. Looking at GSE2703 - the rhesus circadian expression experiment, they have shown 355 genes that are rhythmically expressed. This is not a great experiment because ...


4

I have to say that this seems like a really odd approach to figuring out your diet. The question of whether insulin increases satiety has been more specifically studied in the literature, as has the satiety generated by equicaloric portions of various kinds of foods, as have the actual effects of various specific diets in human feeding studies. If you do a ...


4

The release of the hormone melatonin is responsible for the feeling of sleepiness. It is released by the pineal gland and production starts when the light fades, as it's production is inhibited by light stimulation of the retina, the onset of the production is called dim-light melatonin onset. Artificial supplementation can increase sleep quality and ...


3

Let's assume that pleasure from sexual intercourse might be indicative of some sort of orgasm. Then this would suggest that any evidence of autoerotic behaviour would point to the existence of orgasm, or certanly physical pleasure. I found this quotation on the Wikipedia page for Animal sexual behavior, amongst a lot of information about mammals : Many ...


3

On the analytics of melatonin I have here a german language text by the RKI with references. Translated quote: Assay of melatonin is done by serum or sputum using RIA or ELISA. Alternatively, to infer the nightly amount of melatonin secretion it is possible to look for the melatonin catabolic metabolite 6-hydroxy melatonin sulfate (6-OHMS) in ...


3

The gases NO, H2S, CO even have a function in the human body! Nitric oxide is produced in endothel and neurons as messenger, and in macrophages as cause of nitrosative stress for imprisoned bacteria. Hydrogen sulfide is produced in cysteine catabolism and functions as messenger (only recently discovered). Carbon monoxide appears to act as messenger, too. ...


3

IU stands for "International Units" and it is an arbitrarily chosen unit of measure used mostly to quantify hormones, vitamins or various substances found in the blood. The idea is well explained by the Wikipedia article on international units) Many biological agents exist in different forms or preparations (e.g. vitamin A in the form of retinol or ...


3

There is no evidence that postnatal hormone exposure can change the sexual sexual preference of an individual. However atypical hormonal stimulation of the fetus can induce homosexuality. Homosexuality does not develop without a variety of social factors which are up-to-date mostly unexplained. But can develop without hormonal stimulation. As real life ...


3

Prolactin (PRL) is a pleiotropic hormone. More than 300 different functions have been described for it (Bole-Feysot et al., 1998), although probably the most well known/studied1 is the maturation of the mammary gland during pregnancy and subsequent stimulation of milk production. One of the fairly well known situations when PRL increases is after an acute ...


2

As to your main question, I imagine the Paul Allan Brain Atlas has what you're looking for. In 3D even. Human Brain Map D1 Receptor D2 Receptor Also comes in mouse flavored. Offhand, I cannot be of assistance for the second question.


2

There's two phases of a menstrual cycle, before ovulation known as the follicular phase and after ovulation known as the luteal phase. The second phase is not very variable, it's the same length almost always as it is governed by how long the corpus luteum (remnants of the follicles after the ovum bursts out) survives. The first part is variable and is what ...


2

You are mistaken in that the "lipid hypothesis" has no physiological basis like the carbohydrate biological pathways. Lipids and carbohydrates are produced and catabolized mutually from each other in the body. It's all the calories that matter (okay, proteins have a few too). Once the fat is in the body it gets turned into an energy source but it appears you ...



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