The relationship between serum testosterone and luteinizing hormone (LH) levels in male patients. Source: Dutta, 2017.

A Working Group on low testosterone in overweight and obese men: is it a good idea to suppress LH with testosterone replacement therapy in asymptomatic men?

If overweight or obese men have no symptoms of hypogonadism, further alteration of their hormonal profile with a testosterone replacement therapy is a questionable decision.

Circadian testosterone fluctuation in athletes and in sedentary. A Test.

Which of the two curves is “better”? And which curve of testosterone do you want to have?

Mean serum levels of glucose, insulin, prolactin, LH, and total testosterone in metabolically healthy eugonadal men before and 3 h following an oral mixed meal load. Source: Gagliano-Jucá, 2018.

Both oral glucose and a mixed meal lower testosterone in healthy men.

Is it possible that elevated fasting blood glucose chronically suppresses testosterone levels by acting at GnRh releasing neurons? This is not excluded. Thus, if we take the same example of Shawn Baker, we can see low levels of testosterone. And while there may be other factors that influence Shawn’s testosterone levels, a causal link between Shawn’s high fasting blood glucose and low testosterone can not be excluded.

A laborious but wrong diagram of testosterone regulation in obesity.

A Test of Physiological Literacy: Explain why the diagram below is wrong.

Delayed ejaculation and loss of sensitivity during sexual intercourse are relatively common symptoms in people who follow the popular carnivore, ketogenic and low carb diets.

Objective symptoms of low testosterone on carnivore, ketogenic, low carb, or other restrictive diets.

Delayed ejaculation (DE) is one of the objective symptoms of hypogonadism.

Baseline values for testosterone, LH, FSH. Source: Pearce and Tremellen, 2019, For: "Low testosterone in overweight men: why luteinizing hormone does not go up to compensate?"

Low testosterone in overweight men: why luteinizing hormone does not go up to compensate?

A Test of Physiological Literacy.

Figure 1. GT1 cells maintained in high glucose concentrations demonstrate lower amplitude of GnRH secretion during the initial 45 minutes of sampling Presented data represent a single experiment (six replicates per condition) following 72 hour exposure of cells to respective glucose concentrations GnRH secretion by cells maintained in high and low glucose media, presented as box-whiskers plots. The box represents the interquartile range, the horizontal line represents the median and whiskers the range. Note the higher amplitude of GnRH secretion at 0, 15, 30 and 45 minutes in cells maintained at low glucose concentrations. The differences are of statistical significance at 30 minute sampling interval (*).

Glucose-induced toxicity in GnRH releasing neurons in vitro.

Normally, when testosterone drops, the feedback mechanism should stimulate LH secretion to compensate for the drop in testosterone level. This, however, is not observed systematically after meals.

The perils of postmenopausal hormonal profile.

Last update and review: November 11, 2019. Physiologically literate people have solid reasons to be optimistic about male reproductive … More

Physiological Literacy, Male Longevity: Even flawed medical textbooks represent overall correctly the fact the men at 80 continue producing the same amount of sperm, 100% of the maximal level. The same is true for testosterone in healthy.

Testosterone and sperm production in octagenarian males.

There is a piece of Physiological Literacy that should inspire optimism in every man who learns it. Indeed, it turns … More