What is Dopamine?
Dopamine is an important neurotransmitter in the brain and body, having a role in emotion, motor control, focus maintenance, working memory, and reward and pleasure pathways. An imbalance in dopamine levels can be linked to addiction, depression, apathy, Parkinson’s disease, ADHD, schizophrenia, and psychosis.
What is Testosterone?
Testosterone is a sex hormone produced primarily in the gonads and secondarily in the adrenal glands. It is responsible for libido, vitality, bone density, fat distribution, muscle strength and mass, facial and body hair, sperm production in males, and red blood cell production. Unbalanced testosterone levels can lead to decreased sexual desire, changes in sleep, reduced muscle mass, and reduced self-esteem.
Dopamine-Testosterone bidirectional relationship
Dopamine and testosterone have a bidirectional relationship that is especially important for male sexual function. Dopamine can influence testosterone, and testosterone can influence dopamine. Studies have shown that microinjecting dopamine agonists into the medial preoptic area of rats can increase sexual activity, and that castrated male rats had no interest in fornicating and no dopamine release in the medial preoptic area until they were given testosterone injections, which increased their dopamine release in the area. This demonstrates how dopamine and testosterone are both necessary for libido, and how they work together to regulate each other.
A study conducted by Li et al. (1992) revealed the effect of dopamine on testosterone production. In this study, dopamine agonist was administered in rat brains, resulting in a 67% increase in GnRH mRNA. This mRNA is involved in the replication of DNA for the production of GnRH, which is essential for the synthesis of testosterone. Therefore, the study concluded that dopamine is necessary for the production of testosterone.
The Hypothalamic-Pituitary-Gonadal Axis
The production of testosterone is controlled via a specific feedback loop called the hypothalamic-pituitary-gonadal axis. The hypothalamus secretes a gonadotropin-releasing hormone (GnRH), which signals the pituitary gland to secrete luteinizing hormone (LH), which in turn signals the gonads to produce testosterone.
Consult with an HRT specialist for dopamine & Testosterone levels checkup
If you are a man with low libido, it is vital to have your testosterone and neurotransmitter levels checked. Your doctor may recommend targeted nutritional therapy if dopamine levels are low, as this may help to restore them and support a healthy sex life.
Dominguez JM, Hull EM. Dopamine, the medial preoptic area, and male sexual behavior. Physiol Behav 2005;86: 356-368
Li S, Pelletier G. Role of dopamine in the regulation of gonadotropin-releasing hormone in the male rat brain as studied by in situ hybridization. Endocrinology 1992;131(1):395–399.
Putnam SK, Du J, Sato S, Hull EM. Testosterone Restoration of Copulatory Behavior Correlates with Medial Preoptic Dopamine Release in Castrated Male Rats. Hormones and Behavior 2001;39(3):216–224.
Sexual health. Testosterone therapy: Potential benefits and risks as you age. Available at: http://www.mayoclinic.org/healthy-lifestyle/sexual-health/in-depth/testosterone-therapy/art-20045728. Accessed March 4, 2016.