ABSTRACT
Hormone replacement therapy (HRT) is increasingly being used for various indications in healthywomen. However, there are concerns about its use in women with certain existing clinical conditions. This stems largely and inappropriately from the adverse side-effects seen with the synthetic high-estrogen dose oral contraceptives used in the 1960s. Among these side-effects was impairment of glucose tolerance, resulting in cautions being issued against their use in diabetics. Oral contraceptive therapy and postmenopausal HRT resemble each other in that both involve administration of estrogens, usually in combination with a progestogen. However, they are entirely different in that the former requires supraphysiological estrogenic activity for suppression of ovulation, whereas the latter only requires that a state of hormone deficiency be alleviated. As well as suppressing ovulation, excessive estrogen action induces metabolic disturbances which lead to impairment of carbohydrate metabolism. Principal among these is an increase in corticosteroid activity 1 , which causes resistance to the glucoregulatory actions of insulin. These changes are not seen with physiological estrogen replacement. In fact, to the contrary, physiological estrogen replacement appears to be associated with an improvement in carbohydrate metabolism.
