Monday, August 17, 2009

Growth hormone replacement in adults: interactions with other pituitary hormone deficiencies and replacement therapies

Helena Filipsson and Gudmundur Johannsson

H Filipsson, Endocrinology, Göteborg, Sweden
G Johannsson, Endocrinology, Medicin, Gothenburg, SE-413 45, Sweden

Correspondence: Gudmundur Johannsson, Email:

Severe growth hormone deficiency (GHD) in adults has been described as a clinical entity. Some of the features associated with GHD could, however, be due to unphysiological and inadequate replacement of other pituitary hormone deficiencies. This may be true for glucocorticoid replacement that lacks a biomarker making dose titration and monitoring difficult.

Moreover, oral oestrogen replacement therapy decreases insulin growth factor 1 (IGF-I) levels compared to transdermal route, which attenuates the responsiveness to GH replacement therapy in women. In addition, in untreated female hypogonadism, oral oestrogen may augment the features associated with GHD in adult women. Important interactions between the hormones used for replacing pituitary hormone deficiency occur. Introducing GH replacement may unmask both an incipient adrenal insufficiency and central hypothyroidism.

Therefore, awareness and proper monitoring of these hormonal interactions are important in order to reach an optimal replacement therapy. This review will focus on the complex hormonal interactions between GH and other pituitary hormones in GHD and in GH replacement.