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The Secular Trend is the cause of the failure of American education. This is not caused by teachers' unions, political parties that support teachers' unions, or the environment.  This is the result of a change in population dynamics, that is, again, caused by the Secular Trend.  More money, computers for students, and neither political party can change this.
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A Possible Explanation of Appetite, Obesity, Leptin Resistance, and Type 2 Diabetes.

 

Copyright 2012, James Michael Howard, Fayetteville, Arkansas, U.S.A.

 

Very briefly, I suggest appetite and a connected disorder of appetite found in obesity, leptin resistance, may be explained by the ratio of testosterone to DHEA.

 

It is my hypothesis that testosterone evolved to increase absorption of DHEA by cells / tissues.  I think DHEA was selected by evolution to increase gene activity.  Increased absorption of DHEA was stimulated by increased androgen receptors produced by testosterone.  For example, I think humans evolved because of increased maternal testosterone.  The effect is increased androgen receptors by human brains in utero.  Therefore, our brains, because of increased gene activity, are bigger.  The increased use of DHEA by our brains produced bigger brains at the expense of body development.  My point is that tissues / cells compete for available DHEA.  Optimally, a ratio of testosterone to DHEA is established for proper growth and development and maintenance.  (For more detail regarding the relationship of testosterone and DHEA: “DHEA, Estradiol, Testosterone, and the Relevance of Their Ratio …The Androgen Receptor …and the Secular Trend,” at: http://anthropogeny.com/Androgen%20Receptor%20and%20Secular%20Trend.htm ).  (Humans produce more testosterone than any of the great apes and the amount of testosterone produced by the great apes directly parallels their relatedness to humans.  See the chart at www.anthropogeny.com  .)

 

Leptin reduces appetite.  Leptin is higher in women than men.  Does testosterone reduce leptin?  Sugar and high energy foods decrease testosterone and leptin.  DHEA is higher in men than women.  I think it more likely that DHEA reduces leptin levels.  It does this by increasing leptin receptors.  I suggest that part of the gene activity induced by DHEA results in increased gene activity of various receptor molecules.  Therefore, if testosterone increases DHEA which increases leptin receptors, among others, then measurable leptin will be lower in men than women.  The ratio of higher testosterone in men increases absorption of DHEA which increases leptin receptors which decrease leptin levels.  Now, back again to evolution, lower testosterone may increase appetite in women which would be conducive to fat deposition which would be advantageous to pregnancy. 

 

Leptin resistance is characterized by high levels of leptin.  That is, leptin is not being absorbed.  I suggest this results from low levels of DHEA or low levels of DHEA in cells / tissues because of low testosterone.  Leptin is produced mainly by “white” adipose tissue.  It is known that DHEA reduces white fat production.  Therefore, a normal cycle is produced; when sufficient fat is deposited, leptin is produced to reduce appetite.  I suggest low DHEA allows increased production of white fat which increases leptin.  However, the problem is that obese people produce abnormal levels of white fat and leptin without a reduction in appetite.  Leptin increases without its normal effect.  This is leptin resistance.

 

It is known that testosterone and DHEA are low in obesity.  If testosterone is low, then DHEA does not readily enter cells.  Low DHEA reduces gene activity which, among many things, reduces receptor production, including reduced leptin receptors.  I suggest this results in increased leptin, increased fat production because of lack of appetite reduction, and a cycle which further increases fat and its production of leptin, or leptin resistance. 

 

Since testosterone and DHEA both decrease with age, aging increases fat deposition and appetite.  It is part of my work that the “secular trend” is caused by testosterone.  (You can see my explanation on the lower, left side of www.anthropogeny.com  .)  Of consequence to this discussion, the secular trend may represent an earlier rise of testosterone followed by an earlier decline of testosterone within our population.  This would result in an early reduction of testosterone and DHEA which would result in increased obesity and leptin resistance.

 

I suggest the common problem, “insulin resistance,” is caused by the exact mechanism just described above but involving insulin receptor production.  This could, therefore, explain why type 2 diabetes is increasing directly parallel to obesity.  Many, many researchers attribute the increase in type 2 diabetes to obesity because of this parallel increase.  I suggest they are simply caused by the same thing, which is the alteration in the testosterone to DHEA ratio that is occurring at an increasingly higher percentage with time within our population.

Basics
Population Applications
Welcome to my Blog
 
"Buckle your seatbelt, Dorothy, 'cause Kansas is going bye-bye!"  from "The Matrix"
 

I invite you to read some of my ideas and how they may explain some phenomena that may interest you.  This is my main website.  You may contact me via my email.  Most of what is posted here will also eventually be posted to my main website and, since our ontogeny and phylogeny are closely linked, the information in "Research Applications" and "Population Applications" will be similar.
 
The main prediction of my work that may have direct, practical information is my explanation of the Secular Trend.  This is a composite of all of my work.  If you are only interested in the most significant ideas of my work, please read my explanation of the Secular Trend, just below, and my explanation of human evolution, found in "Basics," just above.  (Picture by Mary Margaret Schisler Howard)
 
 
The Secular Trend

 
"A syndrome, the 'Secular Trend,' is occurring in America and other countries, the cause of which is often attributed to one part or another of the syndrome, itself, and more often attributed to the environment or life style.  I suggest a single cause may be involved that is biological and evidence of ongoing evolution.  The cause may be increased exposure to maternal testosterone within the population with time.  This increase in testosterone produces a decline in dehydroepiandrosterone (DHEA) because testosterone interfere with steroid sulfatase.  If the precursor of DHEA, DHEAS, is not converted to DHEA, DHEA availability is reduced.  It is the reduction in DHEA that is the basis of these problems.  High DHEAS is often found with high testosterone.  A consequence of this is reduced availability of DHEA (just above) and an earlier decline in the production of DHEA during the life span.  This produces increased morbidity during life as well as earlier mortality.

It is my hypothesis that the 'secular trend,' the increase in size and earlier puberty occurring in children, is caused by an increase in the percentage of individuals of higher testosterone. More specifically, I suggest this is due to an increase in the percentage of mothers of higher testosterone with time within the population. This exposes more fetuses to increased maternal testosterone with time within the population. This causes permanent effects in the fetus which persist throughout the life span.  I suggest this is the cause of the parallel increases in morbidity occurring within the population, such as increased infection rates, autism,obesity, hypertension, chronic obstructive pulmonary disease (COPD), cancer, breast cancer, diabetes, the metabolic syndrome, etc., including prematurity, small for gestational age, etc., including less obvious gross effects which later contribute to 'failing schools' and other adverse behavioral outcomes in children.  This includes the new (August,2011) finding of Dr. Kyung Hee Kim of The College of William and Mary that 'creativity' is also declining in children.  This could also explain the increase in negative pregnancy outcomes, re: the increase in the increasing 'newborn death rate' in the United States.
 
I have come to the conclusion that the 'increase in testosterone' may partially be due to a reduction in 'sex hormone binding globulin (SHBG)' as a number of phenomena explained by the secular trend may be based on changes in SHBG.   A decrease in SHBG increases free testosterone levels.  Low SHBG has been found in obese children who do not produce excessive testosterone.  A number of negative phenomena which may be caused by increased testosterone are found with low SHBG and a number of positive effects of reduced SHBG exist.
 
It is my hypothesis that human evolution is driven by increases in testosterone ('Androgens in Human Evolution,' Rivista di Biologia / Biology Forum 2001; 94: 345-362).  This was directly supported by research in 2003; see the chart of testosterone levels in humans and related great apes, upper left at www.anthropogeny.com .  I suggest that periodically testosterone increases excessively and the exposure to excessive maternal testosterone causes negative and evolutionarily consequential changes to the human population.  We may be experiencing this effect at this time.
 
I suggest this increase in testosterone in the population peaks earlier with time.  This earlier peak may produce an earlier decrease in the population with aging.  A number of studies reported in the medical literature have identified low testosterone as a cause of currently increasing disorders.  Therefore, the secular trend may be causing increased morbidity and mortality as a result of excessive testosterone and low testosterone within the population.  Therefore, earlier reductions in testosterone and DHEA could be occurring simultaneously, therefore, reducing the total positive effects of these two major androgens.  This could be the explanation of the severe increase in morbidity that is occurring.  Evolution is increasing earlier reproductive capacity at the expense of post-reproductive years.  The curve of the peak of our androgens is being 'skewed to the left.'
 
As I have said before, I think women of higher testosterone drive the secular trend / human evolution.  I suggest these women produce the highest percentage of premature infants. It has been reported that 'preterm boys' exhibit increased testosterone and the effects of increased testosterone compared to 'full term boys' (J Clin Endocrinol Metab 2010, 'Increased Activity of the Hypothalamic-Pituitary-Testicular Axis in Infancy Results in Increased Androgen Action in Premature Boys.,' Kuiri-Hanninen, et al., J Clin Endocrinol Metab. 2011 Jan;96(1):98-105). What this means is that the population is increasing in women of higher testosterone and this group of women may also be increasing the percentage of men of higher testosterone simultaneously. This could explain why this 'secular trend' can increase so rapidly. This mechanism could expand the percentage of these individuals within a population rapidly and drive human evolution."
 
James Michael Howard
Fayetteville, Arkansas, U.S.A.

 
 
Research Applications
Anthropogeny Blog and the Secular Trend
 
A Study of Human Ontogeny and Phylogeny  (Copyright 1985-2012)