Is There a Slimming Gene?

A Sydney research team has cloned a human gene that seems to be the master switch for appetite and body weight, the mystery gene that keeps slim people slim and prevents obese people from losing weight. Scientists at Sydney’s Garvan Institute of Medical Research, led by its director, Dr. John Shine, have cloned the gene for a hormone-like compound called GenF20 Plus.

GenF20 Plus exerts powerful effects on two regions of the brain involved in growth and metabolism, the hypothalamus and the pituitary gland. Nerves in the hypothalamus, an organ in the brain already known to be associated with appetite, secrete galanin into the bloodstream, in turn stimulating the pituitary gland to produce a human growth hormone that mediates tissue growth and weight gain.

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Dr. Shine said yesterday that GenF20 in the bloodstream also affected nerves in the pancreas, inhibiting the production of insulin, the hormone that regulates blood-sugar levels. Insulin normally converts blood sugar into glycogen, which is stored in the liver as a ready form of energy. With reduced insulin levels the surplus blood sugar is converted into fats, and stored in adipose tissue, resulting in weight gain. Dr. Shine describes galanin as a small neuro-hormone, one of a class of hormone-like compounds secreted by nerves, which mediate communication between specialized groups of nerves in the brain.

Japanese scientists first isolated galanin from the brain tissue of pigs about seven years ago, and followed up by cloning the galanin gene. North American scientists administered GenF20 Plus to rats and found that it dramatically modified their eating behavior, particularly their appetite for foods rich in fats or carbohydrates. Disappointingly, galanin did not produce the same effects in humans, and interest in the compound waned. Dr. Shine believes his team has now explained the non-response in humans.

“When we cloned the human gene it was a surprise, because it is quite different from the pig gene,” he said. Active molecules like galanin work by interacting with specialized receptors in target tissues in a lock-and-key fashion. Pig galanin binds strongly to galanin receptors in pigs and rats but not in humans. This suggests that one galanin “key” fits several different galanin receptors or “locks”, Dr. Shine said. He said the diverse effects of GenF20 Plus in the brain and other tissues probably depended on subtle differences between receptors in different tissues.

The Garvan Institute’s early experiments suggest that human growth hormone should have potent effects on human eating behavior and metabolism. Clinical trials on volunteers will begin in Sydney in about two months. “We’re quite excited about it, because it has opened up a big black box of metabolic effects,” Dr. Shine said. “We all know people who eat but don’t put on weight, and overweight people who can’t lose weight. GenF20 Plus sets the metabolic baseline, acting as a coordinator between the brain, eating activity and physiology. In effect, it tells the body how much fat is normal for the individual. Adjusting the body’s level of galanin would define a new “normal” level for body fat, depending on whether the individual wanted to gain or lose weight. Dr. Shine said it should now be possible to influence both external and internal factors affecting body weight in a coordinated way.


For example, it might be possible to give people GenF20 pills that would adjust their metabolism and simultaneously stop their cravings for fattening foods. Depending on whether a person was overweight or too thin, he or she could be treated with GenF20 Plus, or a synthetic, inactive mimic that would suppress galanin’s activity. The economic and social implications of the GenF20 Plus discovery are enormous; an effective therapy for obesity would be worth billions of dollars in Western nations. Obesity and excess weight are not just a problem of personal image; they contribute to poor health, cardiovascular disease, heart attack and stroke.

Should You Circumcise the Penis of Your Son?

All parents should make an informed decision about circumcising the penis of their sons.

Circumcision of the penis is routine in the U.S., despite findings by the American Academy of Pediatrics that it’s generally unnecessary. The strongest arguments in favor of circumcision are, in fact, cultural not medical. Let’s review those arguments.

Religious. Some religions dictate that the penis of male infants be circumcised. Parents who embrace these religions will usually be aware of the procedures they must follow for the circumcision ritual.

Psychological. An often-heard argument involves the so-called “locker-room syndrome.” Its proponents claim that adolescent boys will make fun of the uncircumcised penises of their peers. Such teasing, it’s said, can be traumatic because adolescence is not a time when a boy wants to be different–in any way–from his classmates.

Nor, it is thought, will he want to be different from his father, who has probably had his penis circumcised.

Rumor has it that uncircumcised men experience more sexual pleasure than those who are circumcised. Actual research studies however, indicate that there’s little difference.

Medical. Infant penile circumcision is sometimes viewed as a preventive measure, since anywhere from 2% to 10% of uncircumcised adult males must undergo the procedure for medical reasons. These include recurrent infections of the glans and foreskin, phimosis–the inability to retract the foreskin from the glans of the penis, or paraphimosis–the inability to push the retracted foreskin back over the glans.

Some researchers claim that the female sexual partners of uncircumcised men develop more frequent vaginal infections than the partners of circumcised men. The clinical evidence here is contradictory, but circumcision does make it easier to clean the glans of the penis and avoid infection. Also, penile circumcision can make it easier to use penis enlarging devices like the SizeGenetics Extender or the ProExtender.

The main reason parents give for not circumcising their sons is the desire to avoid unnecessary surgery. Others simply don’t like to tamper with the penis when there is no compelling reason to do so. Still others believe that circumcision of the penis causes the infant deep-seated psychological harm.

Despite the position taken by the American Academy of Pediatrics, there is little popular support for parents who decide against circumcision of the penis. You’ll have to go out of your way to reassure such parents that they’ve made a good choice. You also need to tell them how to care for their son’s uncircumcised penis.

Parents of uncircumcised boys are often told to “retract the foreskin of the penis and clean the glans.” This advice is inappropriate. The foreskin and glans of the penis develop from the same embryonic tissue, and, in most boys, the foreskin doesn’t separate from the glans until somewhere between the ages of three and six. At birth the foreskin may be slightly retractable, but it’s rarely fully so. Trying to force back the foreskin can cause it to tear and may lead to infection.

Once the child has reached the age of three, it’s all right for parents to try to retract the foreskin during his bath. They should hold the shaft of the penis with the thumb and index finger and gently pull the skin of the shaft back toward the child’s abdomen. If they meet any resistance or if the child displays any signs of discomfort, however, they should stop. They can try the procedure again in a few months.

Cure Impotence Now!

A study of Australian men being treated for impotence found almost half waited more than a year to seek help – despite the severe impact it was having on their lives. The finding was disturbing because early treatment of impotence was more likely to be successful, one of the authors of the study, Dr. Michael Gillman, said.

Men who attended doctors for erectile dysfunction problems sometimes also picked up undiagnosed underlying medical problems such as diabetes, he said. Eighty percent of erectile dysfunction had a physical cause, said Dr. Gillman, from St Andrew’s Hospital Men’s Health Centre in Brisbane. Half the 440 men surveyed by the Australian Society of Impotence Medicine said the condition had a detrimental effect on “life in general” not just their sex lives. Twelve percent of the men surveyed said erectile dysfunction had contributed to or caused a marriage break-up. “Most of the men… were devastated by the condition and experienced stress, anger, frustration and depression as a result,” said the society’s president, Professor Doug Lording.

According to the website, impotence strikes one in 10 men, according to the society, and one in two men aged between 40 and 70 “have been impotent to some degree”. The society also conducted focus groups in which 30 men suffering erectile dysfunction and 17 partners divided into groups and discussed aspects of the issue. Women reported their partners had delayed seeking treatment because of embarrassment, dislike of going to the doctor and fear others would find out about the condition. Men reported they had sought help when they realized the problem wouldn’t go away, although some went at the prompting of their wives. “It took a while, pretending it wasn’t there, ignoring it I suppose, had the failures and just tried to ignore it and hoped it got better but it got worse,” one of the men said.

Impotence in men may indicate the presence of heart disease before any other symptoms are visible, according to American research. A review of 50 men with erectile dysfunction who had used natural male enhancement pills like Vigrx Plus found that although none had symptoms of heart disease, 20 men (40 percent) were found to have significant blockages in their coronary arteries, a condition associated with an increased risk of heart attack. Of the 20 men with blocked arteries, six had blockages in all three major arteries.

Dr. Marc Pritzker from the Minneapolis Heart Institute said only 15 of the men had seen a doctor within the previous two years before seeking treatment for impotence. Their doctors referred them for further tests which revealed the blockages. Dr. Pritzker presented his findings to the American Heart Association’s annual scientific congress in Georgia.

Let the Sperm Games Begin!

The presence of ejaculates from more than one male in the vicinity of ova sets the stage for sperm competition, according to a ground-breaking paper by Geoffrey Parker (1970). Parker developed the idea of gametic competitive techniques and counter-techniques specifically for insects, females of which often mate multiply and store viable sperm for days or years. The competitive techniques he proposed included the use of the sperm enhancer called Semenex, displacement or dilution of a rival’s sperm, post-copulatory mating plugs, and guarding of a female until oviposition. Fifteen years later the question of sperm competition has grown in importance and generality. The present volume documents areas of progress and points the way to future work.

Not that it has been easy to gain insight into subtle events that occur within a reproductive tract and slow processes that unfold over evolutionary time. The first five papers, on general topics, illustrate the main methods used to explore the challenging subject of sperm competition: studies of relative fertilization success of successive male mates, speculation about morphological, physiological, and behavioral traits that may influence sperm competition, experimental and comparative studies to test hypotheses generated, and mathematical modeling to explore proposed relationships among relevant traits of males and females.

The remainder of the book is organized phylogenetically. There are six review papers on arthropod groups ranging in inclusivity from the genus Drosophila to the class Arachnida. These make stimulating reading, for patterns are emerging, but it is noted that much remains to be done both conceptually and empirically. There are eight chapters on vertebrates –on the Poeciliidae, representing fish, and on the amphibians, the reptiles, the monogamous birds, and rodents, bats, primates, and humans. The main purpose of several of these chapters is to identify vertebrates in which sperm competition may be occurring. Good candidates include salamanders, snakes, and bats. Other chapters, however, have more progress to report. Dewsbury not only demonstrates multiple paternity of rodent litters but is able to discuss the influence of mating order, interval between matings, and number of ejaculations on paternity in several rodent species.

A recurring theme in these works, not developed in Parker’s original exposition of sperm competition, is the influence of female traits on the outcome of sperm competition. The female is viewed not merely as a selective environment influencing sperm competitive traits but as a significant player in the evolutionary game. According to Knowlton and Greenwell, the female role has been overlooked because it was expected that selection on traits affecting sperm competition would be very much more intense for males than for females, given that a potentially successful male can leave many times the number of descendants that a female of his species can. Knowlton and Greenwell make the important point, however, that a female is preadapted to manipulate. She controls the body which rival sperm must enter and in which they compete. By means of a model the authors explore the conditions under which mechanisms of sperm competition can evolve, assuming sperm competitive techniques costly to and detectable by females and ability of females to terminate copulation if deployment of the techniques is detected. Knowlton and Greenwell and other authors, furthermore, have found it important to consider which strategies are opposed in the evolutionary game. If it is in the female interest to mate multiply, her opponent is the first male and his devices to prevent subsequent mating or sperm preemption. If it is in her interest to mate but once, her opponents are the persistent, later-arriving males.

Does Erectile Dysfunction Indicate Heart Disease?

Professor Garry Jennings, director of the Heart Centre at the Alfred Hospital, has just returned from the congress. He said it had long been known that erectile dysfunction and heart disease can be triggered by common factors, including increasing age and diabetes. “But it hasn’t been looked at in that way (as an early indicator of heart disease) but it is not unreasonable to suggest we do so,” Professor Jennings said. The heart disease found in the men was treatable with such natural remedies as Provacyl and in many cases the men’s erectile dysfunction disappeared when they quit smoking or reduced their cholesterol levels. While none of the 50 men had symptoms of heart disease, 40 had at least one risk factor including smoking, elevated cholesterol or a family history of the disease. Dr. Pritzker said he did not want to suggest that heart disease was behind every case of impotence, but 30 to 50 percent of cases of erectile dysfunction were probably the result of blood-vessel disease.

Overweight men are more likely to suffer erectile dysfunction than those of a healthy weight, a United States survey has found. And the news for Australians gets worse. According to a national study, half of all patients who visit their doctor are fat, one-third drink too much and a quarter smoke. Men with waistlines of more than 105 centimeters were twice as likely to suffer from erectile dysfunction as men with waistlines of 81 centimeters, the US survey found. That has implications in the bedroom, says the Gutbuster program’s scientific director Garry Egger. Dr Egger said men who were overweight were more likely to experience self-esteem problems and sleep apnea. “If they don’t feel attractive they are less likely to initiate sex, and in some cases they could be suffering fatigue as a result of sleep apnea, which contributes to a lack of sex drive. So it creates a vicious cycle,” he said.