Prolactin is a pretty bad hormone to have elevated at any time. It’s shown to be involved in all kinds of diseases and also (very) negatively affects your body physique wise.
Prolactin can be detrimental to your physique through a few mechanisms as I’ll discuss below.
#1 Prolactin suppresses steroidogenesis
Prolactin inhibits the release of GnRH in the hypothalamus. GnRH starts the whole steroidogenic cascade that ultimately signals the testes to produce testosterone and other steroids. Low GnRH leads to low LH and low androgen production.
This explains why a large percentage of people with high prolactin have low androgens, and this leads to a loss of lean body mass.
Prolactin can slow down muscle gain during a bulk and speed up muscle loss during a cut by inhibiting steroidogenesis.Tweet
#2 Prolactin lowers insulin sensitivity
It does so by reducing adiponectin levels. Reduced insulin sensitivity will lead to elevated blood sugar and inappropriately elevated lipolysis, which is the first step to becoming diabetic.
High blood sugar, as a result of insulin resistance, also promotes the release of prolactin in a feed forward loop.
#3 Prolactin promotes leptin resistance
One of the major causes of obesity is elevated leptin and leptin resistance. Leptin resistance occurs first and as a result the body produces more and more leptin to compensate.
Nevertheless, leptin resistance promotes fat gain and slows the metabolic rate.
Furthermore, leptin promotes thermogenesis (which is the process of burning energy to produce heat), metabolic rate (the increase of energy expenditure), steroidogenesis, etc.
Injecting leptin in fat loss clinics does promote fat loss, but it’s not the best strategy for fat loss because it doesn’t address the leptin resistance, and most of the time, adding more leptin just promotes more resistance.
#4 Prolactin inhibits lipolysis
Fat are released from fat stores through lipolysis. Most fat loss drugs/supplements try to boost fat loss by promoting lipolysis.
And as a side note, promoting lipolysis doesn’t lead to fat loss if that lipolysis is induced by a fast metabolism or physical activity.
This means that prolactin can result in stubborn fat, or the “skinny fat look”, because it lowers lipolysis and limits the amount of fat that can be oxidized (R).
#5 Prolactin increasing lipogenesis
Lipogenesis is the creation of new fat from glucose or amino acids. This disrupts proper energy production from glucose and converts glucose to fat instead of being used for energy production.
The extra fat is then stored in fat cells, which increases fat gain. Then the extra produced fat messes even further with the proper handling of glucose (Randle cycle – substrate compitition) in the body, as seen in diabetics (R).
#6 Prolactin promotes water retention
A few hormones responsible for water retention is aldosterone, vassopressin, oxytocin and ACTH.
Prolactin increases all of them and contributes to a bloated, water retention look (R).
Water retention/edema puts the cell in an inappropriate anabolic state, and not the good kind. The kind that increases the synthesis of fat. This process is also involved in prostate cancer, and lowering prolactin is actually been realized as a candidate for treating prostate cancer.
#7 Prolactin promotes fat storage
Not only does prolactin inhibit lipolysis and promote lipogenesis, it also promotes the storage of the new fat or fat from a meal in adipose tissue.
So if a normal person stores about 50% of ingested fat, someone with high prolactin might stores 80% of the ingested fat. This will lead to fat gain so much faster.
It does so by increasing enzymes (such as GLUT4 and PPARγ) in the fat tissue that promote the storage of glucose and fat; thus promoting visceral and subcutaneous fat gain (R).
#8 Prolactin reduces dopaminergic tone
Dopamine promotes energy production, physical activity, exploration, creativity, novelty, happiness, mental well-being, problem solving, ambition, staying disciplined, etc. (R).
Low dopamine leads to low physical activity, fatigue, addiction and overeating on highly palatable food (R).
And you can just imagine how overeating on palatable food, a.k.a. junk food, leads to fat gain.
When people are treated with dopamine agonists, such as cabergoline and bromocriptine, they show a reduction in total body fat mass, waist to hip ratio, BMI, waist circumference, waist-hip ratio, plasma glucose (by improving insulin sensitivity) and leptin levels (by improving leptin sensitivity) (R). This occurs without changing their diet or lifestyle. Just by lowering prolactin.
#9 Prolactin reduces blood flow
Proper blood flow is needed to supply tissue with oxygen, nutrients, hormones, etc., and reduced blood flow, especially to fat stores, will slow fat loss in that area.
Prolactin reduces blood flow by inhibiting adrenergic receptors, so by using a β-adrenergic agonist will restore normal blood flow.
Moral of the story
Prolactin speeds up fat gain and/or can slow down fat loss. It can even promote diabetes, metabolic syndrome, auto-immune diseases and a whole bunch of other nasty stuff.
All in all, prolactin contributes to a soft, smooth and undesirable physique that isn’t pleasant to have.
If you know of someone who can benefit from this knowledge, please share this article for more awareness.