Both oral and transdermal estrogen increase growth hormone release in postmenopausal women : A clinical research center study

• Published in: The journal of clinical endocrinology and metabolism Vol. 81; no. 6; pp. 2250 - 2256
• Main Authors: FRIEND, K. E, HARTMAN, M. L, PEZZOLI, S. S, CLASEY, J. L, THORNER, M. O
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 01-06-1996
• Subjects: Administration, Cutaneous; Administration, Oral; Aged; Aged, 80 and over; Biological and medical sciences; Estradiol - administration & dosage; Estradiol - blood; Estradiol - pharmacology; Estrone - blood; Female; Gonadotropins - blood; Growth Hormone - blood; Growth Hormone - metabolism; Hormones. Endocrine system; Humans; Insulin-Like Growth Factor I - metabolism; Lipids - blood; Luminescent Measurements; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Postmenopause - metabolism; Pulsatile Flow; Sex Hormone-Binding Globulin - metabolism; Human; Replacement therapy; Transdermal system; Menopause; STH; Estrogen; Oral administration; 17β-Estradiol; Estradiol; Ovarian hormone; Biological activity; Protein hormone; Chemotherapy; Adenohypophyseal hormone; Postmenopause; Clinical trial; Female; Sex steroid hormone
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.81.6.2250

To determine if the mode of 17 beta-estradiol (E2) administration affects growth hormone (GH) concentrations, eight postmenopausal women were studied under the following conditions: (1) control (no E2), (2) oral E2 (Estrace, 1 mg every 12 h for 2 weeks) and (3) transdermal E2 (Estraderm patch, 0.1 mg, two patches changed daily for 2 weeks). Blood was collected every 5 min for 24 h and assayed for serum GH concentrations using a sensitive chemiluminescence assay. Serum E2 levels were comparable during both E2 treatment regimens when measured with a specific chemiluminescence assay. The 24-h integrated GH concentrations (IGHC, min . micrograms/L) increased in all eight subjects from (mean +/- SE) 494 +/- 102 during control to 860 +/- 111 (P < 0.05) and 832 +/- 149 (P < 0.05) during oral and transdermal E2, respectively. Both E2 treatments significantly increased GH pulse height, individual pulse area, incremental pulse amplitude, interpeak valley concentration, and interpeak valley nadir (as measured by Cluster algorithm) when compared with control. No significant differences were observed in the number of GH pulses per 24 h. Insulin-like growth factor-I (IGF-I, micrograms/L) concentrations decreased from 165 +/- 19 (control) to 109 +/- 11 (oral E2, P < 0.05) and 122 +/- 15 (transdermal E2, P < 0.05). No statistically significant differences in attributes of pulsatile GH release or IGF-I concentrations were observed between the oral and transdermal E2 treatments. We conclude that both oral and transdermal E2 treatment increase serum GH concentrations in postmenopausal women. This increase is manifested by larger GH pulses and higher basal (interpulse) GH levels, not by changes in pulse frequency. Both routes of E2 administration decrease serum IGF-I concentrations, which may attenuate IGF-I negative feedback on pituitary somatotrophs and hypothalamic somatostatin secretion, resulting in enhanced pulsatile GH release.