Pituitary, ovarian and endometrial effects of graded doses of medroxyprogesterone acetate administered on cycle days 7 to 10.
Eighteen apparently healthy women with normal menstrual cycles were studied during a control cycle and then during a treatment cycle, in which graded doses (2.5, 5.0 and 10 mg/day) of medroxyprogesterone acetate (MPA) were administered orally on cycle days 7 to 10. In both the control and the treatment cycle peripheral blood was drawn daily for the assay of luteinizing hormone (LH), estradiol (E2) and progesterone (PROG) and an endometrial biopsy was taken on cycle day 11. The lowest dose of MPA (2.5 mg X 4) did not influence the various cycle characteristics. Administration of higher doses (5.0 or 10 mg X 4) resulted in a lengthening of the duration of E2-peak (P less than 0.05), an increase in the area under the E2-peak (P less than 0.05), a decrease in the area under the PROG-curve (P less than 0.05) and a reduction in the height of the LH-peak (P less than 0.05). Furthermore, in 5 of these 12 subjects there was no ovulatory-like PROG-pattern during the cycle in which MPA was administered for 4 days. Morphometric analysis of the endometrial biopsy specimens revealed that the administration of MPA increased the diameter of endometrial glands (P less than 0.01) and the number of vacuolated glandular cells (P less than 0.001), decreased the number of glandular (P less than 0.01) and stromal (P less than 0.05) mitoses and reduced pseudostratification (P less than 0.001). There was no change in the number of endometrial glands and in glandular epithelial height. No leukocytic infiltration was observed. Dating of the biopsies indicated that all control biopsies were proliferative and all, but one (a suppressed proliferation including predecidual reaction), biopsies obtained after MPA administration were early secretory. The most conspicuous effect of MPA administration was a marked increase in subnuclear vacuolation, which could be demonstrated even at the lowest dose (P less than 0.01).
D000328:Adult; D004717:Endometrium / Q000033:anatomy & histology / Q000187:drug effects*; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008525:Medroxyprogesterone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D017258:Medroxyprogesterone Acetate; D008597:Menstrual Cycle / Q000187:drug effects; D010053:Ovary / Q000187:drug effects*; D010902:Pituitary Gland / Q000187:drug effects*; D011374:Progesterone / Q000097:blood
D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D017258:Medroxyprogesterone Acetate; D008525:Medroxyprogesterone