Simultaneous increases of leptin and gonadotropin-releasing hormone following exogenous estrogen administration in women with normally menstrual cycle.
The aim of this study was to investigate whether administration of exogenous estrogen affects the changes of leptin and GnRH levels in women with normal menstrual cycle. A total of 18 women received a bolus intravenous injection of 20 mg conjugated estrogen (premarin group) at 0800 during the fifth day of menstrual cycle, while another 18 women were administered 20 mL of normal saline as the control group. Fasting blood samples were collected at 0, 4, 8, 24, 28, 32, 48, 56, 72 and 96 hours after injection for analyses of leptin, GnRH, estrone (E(1)), estradiol (E(2)), LH and FSH. Both the mean plasma levels of E(1) and E(2) were significantly increased from 4 hours and significantly sustained elevated levels up to 72 hours after injection of premarin. Simultaneous significant increases of leptin and GnRH levels were observed at 28, 32 and 48 hours after injection, while the controls remained constant. The mean LH and FSH levels were initially suppressed and then significantly increased at 56 and 72 hours after premarin administration. Leptin appears to be involved in the regulation of positive feedback mechanism of estrogen by conveyance of metabolic signal to affect the release of GnRH in hypothalamus, while its participation in the modulation of negative feedback remains unknown.
Lin
Kuo-Cherng
KC
Department of Obstetrics and Gynecology, Changhua Christian Hospital, Institute of Medical Research, Chang Jung University, Changhua 500, Taiwan.
Sagawa
Norimasa
N
Yura
Shigeo
S
Itoh
Hiroaki
H
Fujii
Shingo
S
D000328:Adult; D004967:Estrogens / Q000008:administration & dosage*; D004966:Estrogens, Conjugated (USP) / Q000008:administration & dosage*; D025461:Feedback, Physiological / Q000187:drug effects; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D005498:Follicular Phase / Q000187:drug effects* / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000097:blood*; D006801:Humans; D007031:Hypothalamus / Q000502:physiology; D020738:Leptin / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood; D010053:Ovary / Q000502:physiology; D010902:Pituitary Gland / Q000502:physiology
D004967:Estrogens; D004966:Estrogens, Conjugated (USP); D020738:Leptin; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone