Hypogonadism is a term referring to underactivity of the sexual organs or gonads, sometimes called the male menopause. Hypogonadic men produce smaller than normal amounts of testosterone in their testicles resulting in deficient blood levels of the hormone.
Testosterone is an anabolic steroid. Testosterone creates and maintains the virile functioning of the male sexual organs and all other organs: potency in the gonads, strength in the muscles, energy in the mind and vitality of all the cells and tissues where testosterone plays a role.
By their late teens, males are at their lifetime high levels of testosterone, typically 800 to 1200 ng/dl when blood testing is done.
In adult males, approximately 90 to 95 per cent of testosterone is produced in specialized cells in the testicles called Leydig cells.
Primary hypogonadism denotes testicular Leydig cells have lost the capacity to secrete the hormone at youthful levels. This can be seen in chronic disease states, such as rheumatoid arthritis, renal failure, cirrhosis of the liver, chronic obstructive pulmonary disease, hemochromatosis, AIDs, cancer, by the use of chemotherapy drugs or immune-suppressants.
In this case, gonadotrophins LH and FSH in the brain become raised to a high level, indicating an ongoing effort by the pituitary and the hypothalamus to stimulate testicular activity. High gonadotrophins combined with low testosterone is normally an indicator of classic testicular failure with low testosterone production.
Secondary hypogonadism denotes that the Leydig cell capacity may be unimpaired, but the control glands in the brain are not asking them to use that capacity. The pituitary ought to be dispatching hormonal messengers but if levels of FSH and LH remain low, this would suggest that the problem lies with the central control centre in the pituitary and hypothalamus in the brain not sending requests for more testosterone.
In middle-aged men, it seems secondary hypogonadism is the more common cause of testosterone deficiency. Simply replacing testosterone has no effect or can continue downregulation of testosterone and sperm production.
It is therefore not surprising that only about 5 per cent of impotent men find treatment with testosterone supplementation to be effective and papers concluding that hormonal imbalance is not the major reason for male decline are misleading and inaccurate.
Secondary hypogonadism can be caused by suppressed pituitary or hypothalamic function or brain disorders such as tumours, infarction, trauma, vascular defects, hyperprolactinemia, isolated deficiency of luteinizing hormone or follicle-stimulating hormone, nutritional deficiency or starvation, alcoholism, massive obesity, glucocorticoid drugs, Kallman’s syndrome, radiation, etc.
Besides these straightforward testosterone deficiencies in primary and secondary hypogonadism, there is much-nuanced testosterone deficiency which is far more common and clinically relevant. I discuss this issue in a separate article.