alanhu's blog

An experiment was first conducted on rats to determine how prenatal testosterone in males can change behavior. It was found that rats with more testosterone at a young age had more impulsive decisions than female rats. Then the experiment went onto to include human beings. Male children approximately around the age of 3 with prenatal testosterone were compared to female children around the age of 3. The experiment involved a rewards system where the children were given the option of obtaining an instant reward or waiting to obtain a larger reward. For example, the instant reward would include one marshmallow and if they were to wait the child would be given two marshmallows. The males would choose to have the instant prize knowing that if they waited longer they would have gotten a bigger prize more often compared to females. It showed clear signs of ADHD as the males had more signs of attention problems and overactive behavior.

The study that was conducted was done on mice and its behavior when oxytocin was injected into the mice. Before the injection, the mice were studied, especially their behaviors and how the mothers would treat its children. When oxytocin was injected into the bodies the mother's behavior changed. The mothers started acting more loving towards their children. Oxytocin is boosting the neural signal in the brain that assists in social cues and moments of distress. Oxytocin is the hormone that is released when mice are stress to assist in calming the mice down. When the mother finds that the children are under stress the oxytocin released assists in their increased attention and care towards the children.

Scientists conducted an experiment to test the levels of trustworthiness with testosterone and women. A placebo and testosterone was administered to trustworthy women and untrustworthy women. Oxytocin is a hormone that is released in a pulsatile manner, often when a person makes physical contact with someone else. When a person comes into contact with someone else the hormone is released into the bloodstream. The hormone causes relaxation, positive moods and trust. What scientists found was that the testosterone in females caused a decreased level of trust in women. Which is caused by a decrease in oxytocin levels.

Scientists had found that long term use of opioid medications can cause a change in hormone levels. 65% of males that use opioid medications long term started to develop hypogonadism. Hypogonadism is a condition that causes erectile dysfunction and infertility. It can also cause a loss in muscle mass, hair loss and eventually development of breasts. Another condition is hypocortisolism, low levels of cortisol. Cortisol is responsible for metabolism and immune response. Having low cortisol levels can cuase fatigue, weight loss and mood changes.

Estrous cycles cause changes in hormone levels in females. When hormone levels change it causes alterations within the body. At this point in time females tend to learn more, seek rewards and take in more environmental cues. Hormone levels change depending on the time and part of the day and year. Scientists found that changes in hormone levels have and effect on learning and addiction. The estrous cycle is rhymythic since it occurs for approximately a week in every single month of the year. The rhythmic increase and decrease of hormones causes interactions with neurotransmitters, such as acetylcholine and dopamine. Which increases learning and reward seeking.

Neurotoxins are chemicals that disrupt the nervous system. Neurons send neurotransmitters to other neurons, which is the form of communications organisms use to communicate within its body. Neurotoxins block the neurotransmitter receptor sites, so the signal would not be transmitted. The genes have evolved to produce a neurotoxin called clacicludine. Calcicludine is a 60-amino acid long polypeptide. The amino acid is made up of six cysteines which form three disulfide bridges. The disulfide bridges that are formed provide a stable structure for the calcicludine. The bonds inhibit any extra folding of the proteins, meaning that the protein would remain in its shape. A change in the shape of a protein would change the function of that particular protein. The three disulfide bonds that calcicludine has means that the development of the venom has become important to the survival of the eel. Calcicludine is a protein that blocks voltage-gated calcium channels.

Obesity is not only a problem within itself but it can cause more problems later on such as type 2 diabetes, heart disease and more. Knowing that a single disease can lead to may other diseases sparked my interest as there may be a solution. Ghrelin is a peptide hormone that increases a person's hunger and causes the pituitary gland to secrete a growth hormone. Blocking the receptor for ghrelin would not be a wise choice because it could also cause changes in behavior and mood. Scientists then thought about blocking the pathway of ghrelin, which led them to find the molecule YIL781. YIL781 is specifically a molecule that is released by ghrelin that causes the feeling of hunger. Therefore, ghrelin can change the intensity or probability of behaviors. Which influences the number of ghrelin being released and binding to the receptors changes throughout the day as the person eats and doesn't eat. Ghrelin would have different intensities depending on the time of day. 

Exercise assists in maintaining the health of a person. New studies have found that exercise can also assist the brain in resisting Alzheimer’s disease. Mice were used in the study to see whether irisin had a role in increasing brain function. Mice with dementia were injected with the irisin protein and was found to do better on memory tests. Irisin is created through the cleavage of FNDC5 protein. FNDC5 increases through exercising, when you exercise more it would cause more FNDC5 to be cleaved and more irisin secretion. Irisin works by causing a change in gene expression of the beta amyloid.

Progesterone is a hormone that is present in males and females, specifically fathers and mothers. It is a hormone that affects the parental instincts. When progesterone inhibitors were introduced to mice, it was found that they act less aggressively towards its young. Whereas the control showed the male mice being aggressive to its young, tearing up the litter and not being around for the young. In mothers or females, it affects the rate of reproduction and maternal behavior. It allows the female to go through changes that supports young. Such as production of milk.