title: Potency of progestogens used in hormonal therapy: toward understanding differential actions.
abstract: Progestogens are widely used in contraception and in hormone therapy. Biochemical and molecular biological evidence suggests that progestogens differ widely in their affinities and transcriptional effects via different steroid receptors, and hence cannot be considered as a single class of compounds. Consistent with these observations, recent clinical evidence suggests that, despite their similar progestogenic actions, these differences underlie different side-effect profiles for cardiovascular disease and susceptibility to infectious diseases. However, choice of progestogen for maximal benefit and minimal side-effects is hampered by insufficient comparative clinical and molecular studies to understand their relative mechanisms of action, as well as their relative potencies for different assays and clinical effects. This review evaluates the usage, meaning and significance of the terms affinity, potency and efficacy in different models systems, with a view to improved understanding of their physiological and pharmacological significance. This article is part of a Special Issue entitled 'Menopause'.
authors: Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7700, South Africa. Electronic address: Janet.Hapgood@uct.ac.za.
authors: J P
authors: JP
authors: Hapgood
authors: Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa.
authors: D
authors: D
authors: Africander
authors: Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa.
authors: R
authors: R
authors: Louw
authors: Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7700, South Africa.
authors: R M
authors: RM
authors: Ray
authors: Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa.
authors: J M
authors: JM
authors: Rohwer
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D015914:Estrogen Replacement Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D011372:Progestins / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D011987:Receptors, Steroid / Q000378:metabolism
chemical_list: D011372:Progestins; D011987:Receptors, Steroid
keywords: Affinity; Efficacy; Potency; Progestin; Progestogen; Steroid receptor