I am a type 2 diabetic. Low SHBG is par for the course with type 2 diabetes and so is hypogonadism. I was building muscle with a total-T of 240, a free-T of 8.2, and an SHBG of 22. I had no low-T symptoms other than lack of libido and non-responsiveness to phosphodiesterase 5 (PDE5) inhibitors. I underwent coronary artery bypass graft surgery last fall, which resulted in the removal of testosterone replacement therapy (TRT). It is now believed that hypergonadal diabetic non-response to PDE5 inhibitors is due to Rho kinase overexpression (the Rho-associated protein kinase 1, or ROCK1 isomer to be exact). Rho kinase works in the opposite direction of nitric oxide synthase (NOS). It keeps corpus carvenosum in its contracted state by increasing Ca2+ (NOS activity results in the reduction of Ca2+); therefore, even though nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) are increased while PDE5 is inhibited with the use of a PDE5 inhibitor, an erection does not occur because of ROCK1 overexpression keeps the corpus cavernosum from relaxing. If my experience is any gauge, addressing hypogonadism does fix non-response to PDE5 inhibitors in diabetics. With 60mg of Axiron, my total T was only 398 and my free T was only 12.6 on my last visit to my endo, but I have the libido I had in my twenties and erection firmness like I had in my teens with a PDE5 inhibitor (I may not look it, but I am in my mid-fifties). I have also put on 10lbs of muscle since my avatar was shot (my total-T was 240 and free-T was 8.2 when that photo was shot). I am prime example of why total-T is not as important as free-T in a lot guys. My endo told me that my problems would go away when I reached a free-T of 12, and she was right.
