18,19-Dinorpregn-4-en-20-yn-3-one, 13-ethyl-17-[(1-oxohexyl)oxy]-, (17α)- (9CI)

Levonorgestrel butyrate is a manufactured hormone used in a number of birth control methods. In pill form, it is useful within 120 hours as emergency birth control. It becomes less effective the longer after sex and only works before pregnancy has occurred. It is also combined with an estrogen to make combined oral birth control pill. Within an IUD, it is effective for long term prevention of pregnancy. An implantable form of levonorgestrel is also marketed in some countries.

The effects of the synthetic progestin levonorgestrel (LNG) on basal and LH-stimulated progesterone production were studied in collagenase-dispersed luteal cells obtained from 9-day pregnant rats. Luteal cells responded to ovine LH (oLH) with an increase in progesterone output which was maximal at a dose of 100 ng/ml. On the other hand, a dose of 10 microM LNG suppressed the stimulation of progesterone secretion induced by oLH, dibutyryl-cAMP and pregnenolone._x000D_ _x000D_ Reference: J Steroid Biochem Mol Biol. 1994 Aug;50(3-4):161-6. https://pubmed.ncbi.nlm.nih.gov/8049144/

The effects of levonorgestrel (LNG) on serum levels of reproductive hormones and their receptor mRNA expression in the ovary and uterus of Mongolian gerbils were examined. The results show that serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) increased, whereas serum estradiol (E2) and progesterone (P4) decreased profoundly after LNG treatment. The findings suggest that LNG impairs reproductive hormone receptor expression at the molecular level in Mongolian gerbils._x000D_ _x000D_ Reference: Exp Anim. 2011;60(4):363-71. https://pubmed.ncbi.nlm.nih.gov/21791876/

Levonorgestrel hexanoate is a manufactured hormone used in a number of birth control methods.