Lack of regulation of 11beta-hydroxysteroid dehydrogenase type 1 during short-term manipulation of GH in patients with hypopituitarism.

• OBJECTIVE: Evidence from long-term clinical studies measuring urinary steroid ratios, and from in vitro studies, suggests that GH administered for longer than 2 months down-regulates 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), thereby reducing cortisol regeneration in liver and adipose tissue. We aimed to measure acute effects of GH on 11beta-HSD1 in liver and adipose tissue in vivo, including using a stable isotope tracer. DESIGN: Observational studies of GH withdrawal and reintroduction in patients with hypopituitarism. METHODS: Twelve men with benign pituitary disease causing GH and ACTH deficiency on stable replacement therapy for >6 months were studied after GH withdrawal for 3 weeks, and after either placebo or GH injections were reintroduced for another 3 weeks. We measured cortisol kinetics during 9,11,12,12-(2)H(4)-cortisol (d4-cortisol) infusion, urinary cortisol/cortisone metabolite ratios, liver 11beta-HSD1 by appearance of plasma cortisol after oral cortisone, and 11beta-HSD1 mRNA levels in subcutaneous adipose biopsies. RESULTS: GH withdrawal and reintroduction had no effect on 9,12,12-[(2)H](3)-cortisol (d3-cortisol) appearance, urinary cortisol/cortisone metabolite ratios, initial appearance of cortisol after oral cortisone, or adipose 11beta-HSD1 mRNA. GH withdrawal increased plasma cortisol 30-180 min after oral cortisone, increased d4-cortisol clearance, and decreased relative excretion of 5alpha-reduced cortisol metabolites. CONCLUSIONS: In this setting, GH did not regulate 11beta-HSD1 rapidly in vivo in humans. Altered cortisol metabolism with longer term changes in GH may reflect indirect effects on 11beta-HSD1. These data do not suggest that glucocorticoid replacement doses need to be increased immediately after introducing GH therapy to compensate for reduced 11beta-HSD1 activity, although dose adjustment may be required in the longer term.

Keyword

11-beta-Hydroxysteroid Dehydrogenase Type 1

genetics

metabolism

Adipose Tissue

White

drug effects

metabolism

Adult

Aged

Drug Dosage Calculations

Gene Expression Regulation

Enzymologic

drug effects

Glucocorticoids

administration & dosage

therapeutic use

Hormone Replacement Therapy

Human Growth Hormone

therapeutic use

Humans

Hydrocortisone

blood

urine

Hypopituitarism

blood

drug therapy

genetics

urine

Male

Middle Aged

Placebos

Time Factors

Withholding Treatment

Young Adult

Publication and Content Type

ref (subject category)

art (subject category)