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Problem Set : Chemical signals in Animals. 1. Define : 1. Autocrine : 2. Paracrine : 3. Endocrine: 4. Hormone : 2 a.Testosterone is a male sex hormone (androgen), which controls development of male sex organs and many other male secondary sex characteristics. The average blood testosterone level in men in their thirties is 700ng/dl. How many nanograms of testosterone would a healthy 70kg, 35 year old man have on average in his body? Amount of blood (in litres) in the body is 8% of body weight (in Kg). b. In young men, infections such as mumps or viral infections, removal of the testes due to cancer or trauma, and certain genetic abnormalities may cause Testosterone Insufficiency i.e testosterone serum level below 350 ng/dl. By how much (in nanograms) does the testosterone level in the person mentioned in 2a have to decrease for him to have the condition mentioned in 2b? 3. Sexual selection arises from differences in mating success between individuals in a population. Male birds defend territories and sing during the breeding season to attract mates. Increases in testosterone levels result in increases in aggression and singing. a. Baseline testosterone levels in male birds are around 0.1ng/mL. If 2 ng/mL of testosterone in the blood causes 8 singing events per hour, and the most successful males are singing 40 times per hour, what is the concentration of testosterone in the blood of these most successful males? 10 ng/mL b. Assume a female bird requires at least 24 singing events per hour to illicit a mating response. You capture a male and find out he has a testosterone concentration of 5.3 ng/mL. How often is this male singing and is he likely to attract a female? 21 times per hour. No c. While continuous increases in testosterone seem to be favored by sexual selection, elevated testosterone levels inhibit the immune system, and can cause susceptibility to disease. If testosterone levels of 10.7 ng/mL are enough to lead to a disease, what is the maximum number of singing events per hour a male can achieve before becoming susceptible to disease? 42 singing events per hour would be the highest. 4. Anabolic-androgenic steroids (AAS), are a class of steroid hormones related to the hormone testosterone. They increase protein synthesis within cells, which results in the buildup of cellular tissue (anabolism), especially in muscles. Synthetic AAS is widely (and sadly!) misused by sportsmen across the world as a performance enhancement drug in-spite of being banned by the sports governing bodies for various ethical and medical reasons. a. List a few medical issues that you think could arise from the use of synthetic anabolic–androgenic steroids. b. Methandrostenolone (Dianabol, Danabol, DBOL) is an anabolic steroid originally developed by John Ziegler and released in the US in the early 1960's by Ciba. DBOL binds to the androgen receptor in our cells and initiates the expression of genes, protein synthesis ultimately resulting in yielding muscle strength in a short space of time. If you were to test the effects of this drug in a mouse whose androgen receptor gene is mutated and hence inactive, what would be your expected results? Why? c. Russian research, based on rat studies, concluded that the most effective dose of DBOL was 0.5mg per kilo of bodyweight. If so, how many moles of DBOL should be consumed by an athlete who weighs 70kgs to extract maximum benefit? The chemical formula of DBOL is C20H28O2 . Atomic mass of carbon, hydrogen and oxygen are 14 amu, 1 amu and 16 amu respectively. d. If an athlete consumes 30mg of DBOL, how many molecules of DBOL is he ingesting? If the half-life of DBOL is 6 hours, how many molecules of DBOL would be present in his blood 24 hours after ingestion? If 1X10 19 molecules of DBOL in blood is the cut-off to test positive in a drug test conducted by WADA (World Anti-Doping Agency), will this athlete test positive 24 hours post-DBOL consumption? 5. Take home question: Find three sports figures who were tested positive for performance enhancing drugs. Research and find the drug they used, its mechanism of action and the associated side-effects. Knowing their harmful effects would you recommend or condemn their use? Write down your findings in less than 500 words and submit it to your TA.