Steroid receptors in the endometrium of women using long acting progestin contraceptive [Norplant]

Norplant is a progesterone only contraceptive subdermal implant which releases continuous low lose of progestin. It is long lasting, effective and reversible. Since, progesterone has an antiestrogenic effect which involves inhibition of estrogen receptors, this prolonged progestin may have an effect on the steroid receptors content of the endometrium. This work involved study of the estrogen and progesterone receptors in the endometrium of norplant users by immunohistochemical staining of paraffin embedded endometrial biopsy. The study included three groups of norplant users each formed of 20 cases. The first group had norplant for one year, the second for two years and the third for three years. A control group of 20 cases who were not under any hormonal therapy was also included. The results showed that in control cases proliferative endometrium had estrogen and progesterone receptors significantly higher than secretory endometrium. There was significant inhibition of both receptors in the proliferative endometrium of norplant users than control cases. In secretory endometrium, the receptors were not significantly different in norplant users and control. The period of norplant use did not affect the steroid receptors content. It was concluded that norplant has a depressive effect on the level of endometrial estrogen and progesterone receptors. This may be an additional mechanism to its contraceptive action and may affect future pregnancy

Effects of Norplant [subdermal implants] on serum levels of beta-endorphin: prolactin and gonadotropin

50 parous women were enrolled in a longitudinal study of the effect of Norplant subdermal [long acting levonorgestrel] implant on serum levels of gonadotropins [FSH and LH], prolactin [PRL] and beta- endorphin [beta-Ed] for 5 years user. All of them had children. 40 women only completed the study. 10 married parous women not using hormonal contraception volunteers as control. The Norplant users and the control were similarly studied. Starting by day 5 of their cycle until the next menses, three samples were taken [postmenstrual, midcycle and premenstrual phases]. These samples were collected at the end of one, two up to five years since insertion of Norplant. There was definite improvement in the bleeding pattern with time. Marked inhibition were noticed in the serum levels of LH and FSH surge during the first three years, then elevated to be in the range of normal levels in the last two years. Serum PRL and beta-Ed levels lost there normal cyclicity and sustained at a low or high tonic levels all over the study. This study suggested that, Norplant acts mainly by inhibiting the ovulation through suppressing the LH and FSH surge while, the anovulation may be the cause of cesation of normal pulsatility for both serum beta-Ed and PRL