Effect of norethisterone oenanthate on serum gonadotrophin levels

• Published in: Contraception (Stoneham) Vol. 16; no. 6; pp. 591 - 604
• Main Authors: Fotherby, K., Howard, Geraldine, Shrimanker, K., Elder, M., Bye, P.G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.1977
• Subjects: Climacteric - drug effects; Female; Follicle Stimulating Hormone - blood; Humans; Luteinizing Hormone - blood; Norethindrone - blood; Norethindrone - pharmacology; Reproduction and population
• ISSN: 0010-7824; 1879-0518
• DOI: 10.1016/0010-7824(77)90060-9

Norethisterone oenanthate (200 mg) was injected intramuscularly into five postmenopausal women and serum levels of norethisterone, norethisterone oenanthate, FSH and LH were measured. Although the extent of suppression of gonadotrophins varied between the subjects (from 30–75% of control values for FSH and from 50–80% for LH), the degree of suppression of FSH and LH in any one subject was similar. The amount of gonadotrophin suppression was not related to the serum norethisterone levels. The half-lives for norethisterone and norethisterone oenanthate varied from 5.8–15.0 days and from 3.8–12.0 days, respectively. Three of the five women metabolised norethisterone and norethisterone oenanthate very rapidly, and in these women plasma levels of norethisterone had declined to undetectable values within eight weeks of injection.