Progesterone-Like Activity of a Series of 19-Nortestosterones

Interactions Between Oestradiol and Progestogens in the Uterus of the Mouse

“…In a recent study, Edgren, Peterson, Johnson & Shipley (1961), were able to obtain only partial blockage of oestrogenic interruption of pregnancy in rats with progesterone. Thus it seemed desirable to re-investigate the problem, using a wide range of doses of progesterone and also certain of the 19-nortestosterones, which are potent progestogens (Saunders, Colton & Drill, 1957). They are also reported as being potent anti-oestrogens in tests involving uterine weight increase in immature mice (Edgren, Calhoun, Elton & Colton, 1959), a property which may not be completely correlated with their progestational potency (Edgren et al 1959).…”

History of the first oral contraceptive

“…This mechanism of action was later confirmed by a variety of experimental and clinical studies (Drill, 1966). Related studies were published (Saunders et a!., 1957a;1957b;Saunders and Drill, 1958;Drill and Riegel, 1958;Drill, 1959aDrill, , 1959b, demonstrating, among other things, that norethynodrel produced a reversible contraceptive effect in the rat (Saunders and Drill, 1958).…”

Effects of Progestogenic Substances on the Uterine Secretion of Spayed Rats Primed with Oestradiol

“…On one side they have been shown to display marked differences in their ability to induce progesterone-like effects in different tests, e.g. in the complete secretory transformation of the endo metrium of oestrogen-sensitized rabbits either by systemic, or by local administration, or in the maintenance of pregnancy in spayed rats or rabbits [McG inty and Djerassi, 1958;Saunders et al. 1957;Edgren et a i, 1966], On the other hand, an estrogen-like activity of some representatives of this group such as norethynodrel.…”