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Growth hormone response to GHRH, GHRP‐6 and GHRH+GHRP‐6 in patients with polycystic ovary syndrome
Author(s) -
Micić Dragan,
Kenderesˇki Aleksandra,
Popović Vera,
Sˇumarac Mirjana,
Zorić Svetlana,
Macut Djuro,
Dieguez Carlos,
Casanueva Felipe
Publication year - 1996
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1996.8380848.x
Subject(s) - medicine , endocrinology , polycystic ovary , insulin , insulin resistance
OBJECTIVE Despite improved diagnostic facilities and advanced in vitro studies, the primary causes of the polycystic ovary syndrome (PCOS) have not been resolved. A defect in the regulation of GH secretion has been suggested in PCOS but the available data are limited and the underlying mechanisms remain unknown. In recent years considerable attention has been devoted to non‐classic GH secretagogues and, in particular, to the series of hexapeptides of which GH‐releasing peptide (His‐ D ‐Trp‐Ala‐Trp‐ D ‐Phe‐Lys‐NH 2 , known as GHRP‐6) is the most representative. GHRP‐6 seems to be a promising tool for exploring GH secretory mechanisms and it has been reported that GHRH+GHRP‐6 is a powerful stimulus to GH secretion. Our aim was to investigate the GH responses to GHRH, GHRP‐6 and the administration of GHRH+GHRP‐6 in two groups of patients (normal weight and obese) with PCOS in comparison with matched control groups.DESIGN All subjects were studied three times on different days with GHRH (100 μg i.v.), GHRP‐6 (90 μg i.v.) and GHRH+GHRP‐6 (100μg+90μg).PATIENTS Sixteen women with PCOS and 22 healthy controls were studied. They were divided into four groups according to BMI: Group A (non‐obese PCOS, n =6, age 21.8±1.7 years, BMI 22.1±0.8 kg/m 2 ); Group B: (obese PCOS, n =10, age 12.7±1.3 years, BMI 32.9±2.1 kg/m 2 ); Group C (non‐obese healthy women, n =13, age 26.8±1.5 years, BMI 21.8±0.6 kg/m 2 ) and Group D (obese healthy women, n =9, age 29.4±4.2 years, BMI 35.7±1.3 kg/m 2 ).MEASUREMENTS Serum GH was measured using a time‐resolved fluoroimmunoassay (Delphia, Pharmacia).RESULTS After GHRH administration significant differences were found between GH peaks in Groups A and B (82.4±16.4 vs 20±4.8 mU/l P <0.05) and in AUC for GH between Groups A and B (4667±1061 vs 847±236, P <0.05) while there were no differences between the same groups in GH peak or AUC after GHRP‐6 administration. There were no significant differences in peaks or AUC for GH after GHRH between Groups A and C, nor between Groups B and D. There were significant differences in GH peaks after combined administration of GHRH+GHRP‐6 between Groups A and B (211±26.4 vs 108±17.6, P <0.05) as well as between GH AUC in Groups A and B (12068±2323 vs 5997±1342, P <0.05). There were no differences in GH peaks or AUC for GH after GHRH+GHRP‐6 administration between Groups A and C or Groups B and D.CONCLUSIONS The impaired GH response to GHRH found in obese PCOS patients is a consequence of obesity and could be a functional defect, since it can be overridden with GHRP‐6 administration.