Testosterone replacement to prevent type 2 diabetes? Not just yet

Analysis of Sex Hormones, Insulin Dosage, and Risk Factors Associated With Male Diabetic Patients

The purpose of this study is to assess the influence of sex hormones and other indicators on risk factors for hypercoagulable states in male patients with type 2 diabetes mellitus. Ninety-two diabetic patients were divided into two groups based on testosterone levels: T1 group (testosterone <12 mmol/L) and T2 group (testosterone >12 mmol/L). Fifty-four non-diabetic patients were used as the control group. Sex hormone index, glucose, insulin, C-peptide, 24-h urinary free cortisol, thromboelastography, and insulin resistance index were measured by radioimmunoassay. Testosterone was lower in the diabetic men than in the control group (12.02 vs 14.77, p < .05), and was inversely related to blood coagulation status, blood glucose level, and cortisol level. Body mass index was positively correlated with estradiol and insulin resistance index. Testosterone was independently associated with the clotting process after controlling for age. Low testosterone is a risk factor for hypercoagulable state in diabetic men. Elevated estradiol and insulin resistance are influential factors for increased body mass index.

Testosterone, Diabetes Risk, and Diabetes Prevention in Men

Middle-aged and older men with lower testosterone concentrations are more likely to have or to develop metabolic syndrome and type 2 diabetes. Central adiposity is a risk factor for metabolic syndrome and diabetes and predisposes to lower testosterone concentrations. Conversely, testosterone treatment reduces fat mass and insulin resistance. In a randomized controlled trial of 1007 men with either impaired glucose tolerance or newly diagnosed type 2 diabetes, 2 years of testosterone treatment on a background of lifestyle intervention reduced the risk of type 2 diabetes by 40%; this demonstrates the potential utility for testosterone pharmacotherapy to prevent diabetes in men.

Development of a single-dose intranasal testosterone administration paradigm for use in men and women

For over two decades, researchers in the field of human social neuroendocrinology have been using single-dose pharmacological challenge protocols to determine the causal effects of testosterone on psychological, behavioural, and neural processes. Most of these single-dose administration studies have so far used (1) single-sex samples and (2) varying modes of testosterone administration (intramuscular, transdermal, sublingual, and intranasal) that produced vastly different dose-response curves. Moreover, whereas studies with male participants increased men's testosterone concentrations within the high normal physiological range, studies with women typically increased testosterone concentrations to supraphysiological levels. The purpose of this study was to develop a single-dose administration protocol using intranasal testosterone that would produce a proportionally similar rise in testosterone for both sexes. We found that an 11 mg intranasal testosterone dose in men and a 0.3 mg dose in women raised testosterone concentrations to the high normal physiological range for each sex, producing similar dose-response dynamics in both sexes. This paradigm will allow researchers to design studies with mixed-sex samples that test physiologically plausible sex differences/similarities in the causal effects of testosterone. It will also provide a replicable protocol to examine the possible adaptive functions of acute increases in testosterone in both sexes.