Prolactin

links: Hormones Neuropeptide reference: Prolactin: Structure, Function, and Regulation of Secretion (Freeman et al., 2000) (practicaly a textbook) 4-11-2021

Prolactin #

AKA luteotropic hormone (LTH). Neuropeptide secreted from the Pituitary Gland.

• Ideal is 4-7ng/dL in men, 10-12 for women. Stimulatory when its level increases within the normal range, and inhibitory when over the normal range. Very delicate, it seems.

• Excessive amounts can lead to asexual tendencies.

• High amounts seen in tumors/Cancer

• I don’t think it’s even necessary for survival. RPF

• More reliable than cortisol as a biomarker of prolonged stress.

• Promotes storage to adipose tissue by increasing certain enzymes (GLUT4, PPARγ, etc. which promote storage of glucose and fat)

• Prolactin decreases beard growth, libido, desire, temp, and increases Acne, Muscle loss, and Hair Loss. It mimics androgen-induced skin symptoms.

• Activates Sebum

• Inhibits Lipolysis and blood flow and increases Lipogenesis, and fat storage

• Promotes Water retention by increasing Aldosterone, Vasopressin, oxytocin, and Adrenocortocotropic Hormone.

• Diagnosis and management of hyperprolactinemia (2003)

  • Can result from Hypothyroidism.

• Prolactin modulation of dehydroepiandrosterone sulfate secretion

  • Increase/decrease in plasma PRL is correlated with corresponding DHEA-S concentrations.

• Prolactin has a direct effect on adrenal androgen secretion

  • PRL potentiates ACTH’s effect on DHEA(-S) - they say prolonged elevation is necessary for prolactin to have an effect on the secretion of adrenal androgens; prolactin alone has no effect.

• Associated with elevated Parathyroid Hormone and vice versa.

• Increases Androgen Receptor density, including in the prostate, consistent with an enhanced secretory activity.

• Increases 5-AR activity, as does DHEA.

• Progesterone and 5α-DHP lower prolactin

• Raised by Melatonin and Estrogen

• Increases Estrogen Receptors. R

• Lowers Progesterone production.

• Stimulates Parathyroid Hormone release and vice versa.

• Long-term hyperprolactinemia reduces the ability of tuberoinfundibular neurons to synthesize Dopamine. Tuberoinfundibular Pathway. R

• D2 is needed for suppression of prolactin, not D1.

• Lowers Insulin and Leptin sensitivity via reducing Adiponectin levels.

Hypoprolactinemia #

• HYPOPROLACTINEMIA AS RELATED To SEMINAL QUALITY AND SERUM TESTOSTERONE
  • <6 ng/mL is hyporpolactinemia, and >26 is hyper.
  • Increases testicular responsiveness to Luteinizing Hormone. Increases oxygen uptake by spermatozoa: enhancing sperm motility.
  • Hyperprolactinemia, and hypoprolactinemia alike for at least some of these, is associated with male infertility, hypogonadism, impotence, oligozoospermia, and azoospermia.
  • The reason why Pineapples and similar fruits supposedly make your cummies tastier is because of its acidic pH. Can’t help but think the Citric Acid content also plays a role.
  • 67% of the hypo group had low serum Testosterone, while only 33% in the hyper group.

Effect of a Dopamine Agonist on Luteinizing Hormone Receptors, Cyclic AMP Production and Steroidogenesis in Rat Leydig Cells (Dirami and Cooke, 1997) #

• Mesulergine 2mg/kg/day for rats (HED = 22.6 @ 70kg) in food @ 1,5,12 wk. The results are pretty brutal. But this might be a very high dose. Metergoline for instance is like 4-8mg.

Effects of chronic bromocriptine-induced hypoprolactinemia on plasma testosterone responses to human chorionic gonadotropin stimulation in normal men (Oseko et al., 1991) #

• Bromocriptine 5mg oral daily for 8 weeks in five men age 20-35.
• I don’t really know what hCG ‘stimulation’ is…

Effects of prolactin on the sensitivity of the testis to LH #