Growth hormone response to thyrotrophin releasing hormone in women with polycystic ovarian syndrome

Recent clinical studies have suggested that women with polycystic ovarian s yndrome (PCOS) may have disturbances of growth hormone (GH) kinetics and th e GH/insulin-like growth factor (IGF)-I system. The knowledge that in vario us metabolic abnormalities there is a paradoxical sensitivity of pituitary somatotrophs to thyrotrophin-releasing hormone (TRH) administration led to this investigation of the GH secretory response to TRH in women with PCOS, Twenty-four women with PCOS and 18 control women were studied. TRH was give n as a single i.v. injection (time 0) and blood samples for GH measurements were obtained at -15, 0, 15, 30, 60 and 90 min. The GH responses were expr essed as the area under the curve (AUC) or the differences from the basal v alue (Delta max), The GH response to TRH(mean +/- SEM) was greater in women with PCOS (Delta max 2.47 +/- 1.73 versus 0.47 +/- 0.06 ng/ml, P < 0.05 an d GH AUC 8.05 +/- 2.10 versus 2.58 +/- 0.18 ng/ ml/90 min, P < 0.05), Accor ding to GH response to TRH, two PCOS subgroups were identified: (i) normal responders (n = 14) who showed Delta max GH response (0.36 +/- 0.06 ng/ml)a nd GH AUC (1.93 +/- 0.64 ng/ml/90 min) similar to that in the controls and (ii) over-responders (n +/- 10) who showed a paradoxical increase in GH con centrations in response to TRH Delta max GH response 5.43 +/- 1.27 ng/ml an d GH AUC 16.62 +/- 3.51 ng/ml per 90 min) that was significantly higher tha n in normally responding PCOS patients (P < 0.0001) or in controls (P < 0.0 001), These data demonstrate an enhanced GH response to TRH administration in a subgroup of women with PCOS.