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25 Cards in this Set
- Front
- Back
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Define androgenic
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Produce masculine characteristics.
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Define anabolic
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promoting synthesis and growth. Opposite of catabolism.
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What is the most potent androgen and where is it made.
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Testosterone. 50x greater in adults than children. Some produce in adrenal cortex (females mainly) but leydig cells make 95% for males. 0.6 microgram/ml for males and 0.03 for females.
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What does LH do?
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LH stimulates testosterone to be produced by the Leydig cells. The testosterone produced acts on leydig cells and sertoli cells to promote spermatogenesis.
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What does FSH do?
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FSH binds to Sertoli cell receptors and promotes spermatogenesis. Spermatogenesis maintained by testosterone once an initial FSH stimulus is applied.
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In general terms describe the levels of testosterone throughout life.
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A couple of surges during gestational development for sex characteristics than right before and after birth. It's then low until puberty and then slowly declines for old age.
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What is testosterone converted to in the cell?
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Dihydrotestosterone by 5a reductase. This is the active hormone in most cells. DHT has much higher affinity and the receptor complex in more readily transported to the nucleus.
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Where is testosterone the active steroid and not DHT.
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Hypothalamus and the pituitary.
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How does testosterone work as a drug
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Not very well. High first pass effect. If injected, it is rapidly metabolized. You also get mixed anabolic and androgenic effects.
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What are the alterations that can be done to testosterone?
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There are three. 17a substitution is tybe B (methyltestosterone) and type C (mesterolone) is ring substitution. These are orally active but not metabolized to testosterone. They are toxic and cancerous. Type A is 17B esterification. Absorption is delayed and is injected this is metabolized to testosterone.
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What is the drug of choice for hypogonadism whether due to chromosomal or something else?
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Enanthate and cypionate because of long half lives. Normal puberty if properly handled. If secondary or tertiary problem you can give gonadotropins like LH and FSH. Androgens not added till puberty.
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If you have seminiferous tubule disease what will be the level of FSH.
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It will be high because sertoli cells are in the tubules. Also, sertoli cells release inhibin when stimulated by FSH that acts on pituitary to stop FSH output.
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What is androgens effect on erythropoiesis.
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Stimulates erythropoietin synthesis and directly recruits stem cells for RBC development. Useful in many anemias EXCEPT aplastic whne it can cause hepatocellular carcinoma.
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Hereditary angioneurotic edema. What is it and how do we treat it?
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Lack of an active inhibitor of the first component of compliment. We use androgens like 17a-alkylated (Danazol) that increase synthesis of inhibitor of complement. ODD-men and women respond equally.
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What is the problem using androgens for growth delay in children?
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They calcify the epiphyseal plates.
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What are some side effects of steroid abuse.
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Virilizing effects in young males and females. Spermatogenesis inhibition b/c you negative feedback other hormones. Small balls. Plasma T levels go down (not with 17B esters though). T can be converted to estrogen by an aromatase in liver giving guys boobs. Roid rage, liver problems, and typical lipid changes.
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How should long acting GnRH analogs be given for positive stimulation.
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Pulsatile form. Continuous can actually lead to suppression.
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How should long acting GnRH analogs be given for inhibition.
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You should give it continuously but it will have an initial flare. Why not use antagonists?? The only ones we have are toxic.
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Ketoconazole
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Inhibits androgen synthesis. Blocks P450s. Requires high doses and can increase estrogen:T ration giving boobs.
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Finasteride
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5a-reductase inhibitors. Used in BPH and maybe prostate carcinoma. Can block hirsutism in women.
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Flutamide and Cyproterone Acetate
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block effect of androgens on target tissue. Useful for excess androgen in women and advanced prostate carcinoma. Often coupled with GnRH agonist.
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Leuprolide acetate and Goserelin
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Long-acting GnRH analogs
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Spironolactone
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Blocks T production but I don't know how.
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How does male contraception work in theory?
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Inhibit Testosterone production by testes and give replacement testosterone at a level low enough for the periphery but not high enough for spermatogenesis.
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Gossypol
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Cottonseed extract. Destroys seminiferous tubules. Normal testosterone. Reversible if taken away. If sperm still produced it decreases their motility (use intravaginally??)
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