Plasma levels of cortisol and corticosteroid binding globulin during use of Norplant-2 implants

Progestins used in endocrine therapy and the implications for the biosynthesis and metabolism of endogenous steroid hormones

Steroidogenesis refers to the de novo synthesis of steroid hormones from cholesterol by a number of sequential enzyme catalysed reactions in the adrenal and the gonads. In addition, circulating steroid hormone precursors are further metabolised in selected peripheral tissues. It has been suggested that the biosynthesis of endogenous steroid hormones can be modulated by progestins, used widely by women in female reproductive medicine. However, as a number of structurally diverse progestins with different pharmacological properties are available, it is possible that these synthetic compounds may vary in their effects on steroidogenesis. This review summarises the evidence indicating that progestins influence the biosynthesis of steroid hormones in the adrenal and gonads, as well as the metabolism of these endogenous hormones in the breast, highlighting the limitations to the current knowledge and directions for future research.

Implantable contraception

Although levonorgestrel contraceptive implants have been available for over 15 years, innovations have only recently led to a wider choice. These new implants offer easier insertion and removal and other advantages depending on the type of progestin. Implants prevent pregnancy by several mechanisms, including inhibition of ovulation and luteal function and alteration of cervical mucus and the endometrium. The high efficacy and ease of maintenance make implants an ideal contraceptive for many women, including adolescents, a population that uses implants infrequently but reports high satisfaction. Implants are appropriate for women who are breastfeeding, who have contraindications to estrogen, or who have diseases such as diabetes, hypertension, sickle cell anemia, or an HIV infection because implants have few metabolic or hematologic effects. Long-term use has not been associated with a decrease in BMD and generally leads to increased blood levels and iron stores. Women who wish to space their pregnancies appreciate the nearly immediate onset of action with insertion and the rapid termination of all effects with removal. All types of implants lead to menstrual changes and other side effects in some women. Adverse effects that occur in implant users more than the general population include headaches and acne. Women must be thoroughly counseled regarding the potential for menstrual alteration, side effects, and sexually transmitted infections if they do not use condoms. Despite their initial high cost, implants are a cost-effective method over several years, even when discontinued before the life of the implant.

Effect of Norplant implants on the pituitary-adrenal axis function and reserve capacity

The present work investigated the effects of Norplant implants on the pituitary-adrenal function among 15 users of Norplant implants prior to and 6 months after insertion of the implants. Serum cortisol levels and their diurnal variations, ACTH and 24-h urinary 17-ketosteroids, ketogenic steroids, 17-hydroxy steroids, and creatinine, were measured. Also, a dynamic test (the 5-h Synacthen depot = ACTH stimulation test) was done before and 6 months after implants insertion. The 9 a.m. cortisol levels were blunted (within the normal ranges) while the 6 p.m. values were unaltered. The 24-h urinary ketogenic, hydroxy, and ketosteroids were also unchanged after Norplant implants use. The ACTH stimulation test showed a decreased adrenal response which was also within normal ranges. These data should raise the question related to suprarenal response to acute or prolonged stresses, such as surgical operations or shock in women using Norplant implants.