The study I refer to shortly after the last break (download the podcast), was conducted by a group of researchers from the Instituto de Ciencias Biomedicas at the Universidad de Chile in Santiago de Chile, dealt with the modulatory effects of testosterone (and aldosterone) on intracellular calcium response in skeletal muscle cell cultures and not the subsequent consequences on contractile force of hypertrophy and could thus only serve as a point of departure for future investigations to either confirm or refute this idea (Estrada. 2010).
Nicotine exposure, brain aromatase and gender-specific implicationsWith the advent of new technologies, esp. the direct observation of aromatase activity in primate brains (Lidstrom, 1998; Kim, 2009; Biegon, 2010), our understanding of the peripheral effects of certain substances on hormone metabolism, one of the latest such insights pertains to the effects of nicotine exposure on the expression of the aromatase enzyme in the brain.
|Table 1: Comparison of the effects of nicotine exposure and the effects of an aromatase inhibitor (at different time points in life) on sexual behavior, anxiety and depression, hot flashes, and weight gain in men and women (Biegon. 2012)|
If you take a look at the overview in table 1, you will however realize that other effects as the anxiolytic effects of acute nicotine exposure in adult women or the weight loss effect (which is certainly another reason women like to smoke) stand in direct opposition to the hypothesis that the majority of nicotines beneficial and negative side-effects were mediated by its effects on the aromatase enzyme. Fortunately, for most smokers, this appears to apply to the pro-Alzheimer's effects of low brain aromatase (Hiltunen. 2006), as well - at least, if we go by the conflicting results of the latest epidemiological studies, which contradict earlier findings that did even suggest that smokers would have a lower risk of Alzheimer's disease.
Alzheimer's, dementia, etc. are yet only examples of the far reaching effects brain aromatase and its regulation by nicotine and other substances such as aromatase inhibiting drugs, but also all sorts of environmental toxins with endocrine side-effects could have - so you can easily expect more interesting study results in the future.
Other news that did not make it into the showAs I have mentioned in the introduction, we did cover a hell lot of ground, so that most of the other studies are directly related to the luteinizing hormone negative feedback and thus no real "news" - I skipped discussing those, since I though that everyone listening will get the main message and did not want to bore those of you who are not interested in this topic with a show solely on the effects of nutrient deprivation and exercise on the endocrine milieu. But enough of the excuses, there is still more:
- Right-left digit ratio (2D:4D) predicts testosterone response to exercise in 79 professional Rubgy players (Kilduff. 2012) - In the analysis, researchers from the Swansea University at the Sports Science, Talbot Building in Singleton Park, Swansea, UK, found that despite significant differences in basal testosterone levels, the 2D:4D ratio, which is generally regarded as an indicator of in-utero androgen exposure was significantly associated with a lower testosterone response to repeated sprint-agility tests in the 25 subjects who participated in the active arm of the study.
- Caffeine prevents weight gain and cognitive impairment by high fat diet (Moy. 2012) - This is not news? Just read on, you will soon realize that it is news! Firstly, the scientists from the University of Albany identified an ameliorative effect of caffeine on the diet-induced reduction of hippocampal expression of the brain-derived neurotrophic factor (BDNF) as the underlying mechanism behind it's neuroprotective effect (the same stuff that's also increased by exercise, by the way).
And secondly, the rodents received only a single, weekly intraperitoneal injection that would be equivalent to ~250mg in a human being (I double checked, the study says: "All animals received either caffeine (20 mg/kg) or saline (volume-matched), i.p., once weekly."; my emphasis in Moy. 2012). If that's not a mistake, chronic caffeine consumption may not even be necessary to see a hell-lot of the anti-diabetes and anti-neurological damage effects of coffee - just 2 cups once per week that's it!
Figure 2: Assuming this is not a mistake in the study caffeine once a week would be enough to boost the BDNF levels of junk-food and normal eaters alike (Moy. 2012)
And if you look closely at the data in figure 2 you see that even "normal" people may benefit from this regimen.
- Insulin has anti-Alzheimer's effect - Yeah you read me right. It reduces the formation of ameliod beta plague (read more)
- Yet more plant extracts with natural anti-cancer activity: Chamaejasmenin B and neochamaejasmin C isolated from the root of Stellera chamaejasme L known in TCM as Rui Xiang Lang D (read more)
- Want to father a Nobel Laureate and in your early to late 30s? Than its about time you procreate! Study finds U-shaped curve for father's age and intellectual abilities of the offspring peaking at 32-37 years or so (read more)
- ...plus the rest I did not mention (read all)
- Biegon A, Kim SW, Alexoff DL, Jayne M, Carter P, Hubbard B, King P, Logan J, Muench L, Pareto D, Schlyer D, Shea C, Telang F, Wang GJ, Xu Y, Fowler JS. Unique distribution of aromatase in the human brain: in vivo studies with PET and [N-methyl-11C]vorozole. Synapse. 2010 Nov; 64(11):801-7.
- Biegon A, Alia-Klein N, Fowler JS. Potential contribution of aromatase inhibition to the effects of nicotine and related compounds on the brain. Front Pharmacol. 2012;3:185.
- Daniell HW. Osteoporosis and smoking. JAMA. 1972 Jul 31;221(5):509.
- Estrada M, Liberona JL, Miranda M, Jaimovich E. Aldosterone- and testosterone-mediated intracellular calcium response in skeletal muscle cell cultures. Am J Physiol Endocrinol Metab. 2000 Jul;279(1):E132-9.
- Hiltunen M, Iivonen S, Soininen H. Aromatase enzyme and Alzheimer's disease. Minerva Endocrinol. 2006 Mar;31(1):61-73.
- Korkor AB, Eastwood D, Bretzmann C. Effects of gender, alcohol, smoking, and dairy consumption on bone mass in Wisconsin adolescents. WMJ. 2009 Jul;108(4):181-8.
- MacMahon B, Trichopoulos D, Cole P, Brown J. Cigarette smoking and urinary estrogens. N Engl J Med. 1982 Oct 21;307(17):1062-5.
- Moy GA, McNay EC. Caffeine prevents weight gain and cognitive impairment caused by a high-fat diet while elevating hippocampal BDNF. Physiol Behav. 2012 Dec 6.
- Nusbaum ML, Gordon M, Nusbaum D, McCarthy MA, Vasilakis D. Smoke alarm: a review of the clinical impact of smoking on women. Prim Care Update Ob Gyns. 2000 Sep 1;7(5):207-214.
- Pant S, Shapiro CL. Aromatase inhibitor-associated bone loss: clinical considerations. Drugs. 2008;68(18):2591-600.
- Roselli CE, Abdelgadir SE, Ronnekleiv OK, Klosterman SA. Anatomic distribution and regulation of aromatase gene expression in the rat brain. Biol. Reprod. 1998; 58, 79–87.
- Roselli CE, Resko JA. Cytochrome P450 aromatase (CYP19) in the non-human primate brain: distribution, regulation, and functional significance. J. Steroid Biochem. Mol. Biol. 2001; 79, 247–253.