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  • Author: Ruth Andrew x
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Lack of regulation of 11β-hydroxysteroid dehydrogenase type 1 during short-term manipulation of GH in patients with hypopituitarism

Helga A Sigurjonsdottir, Ruth Andrew, Roland H Stimson, Gudmundur Johannsson and Brian R Walker

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 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), thereby reducing cortisol regeneration in liver and adipose tissue. We aimed to measure acute effects of GH on 11β-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 9,11,12,12-2H4-cortisol (d4-cortisol) infusion, urinary cortisol/cortisone metabolite ratios, liver 11β-HSD1 by appearance of plasma cortisol after oral cortisone, and 11β-HSD1 mRNA levels in subcutaneous adipose biopsies.

Results

GH withdrawal and reintroduction had no effect on 9,12,12-[2H]3-cortisol (d3-cortisol) appearance, urinary cortisol/cortisone metabolite ratios, initial appearance of cortisol after oral cortisone, or adipose 11β-HSD1 mRNA. GH withdrawal increased plasma cortisol 30–180 min after oral cortisone, increased d4-cortisol clearance, and decreased relative excretion of 5α-reduced cortisol metabolites.

Conclusions

In this setting, GH did not regulate 11β-HSD1 rapidly in vivo in humans. Altered cortisol metabolism with longer term changes in GH may reflect indirect effects on 11β-HSD1. These data do not suggest that glucocorticoid replacement doses need to be increased immediately after introducing GH therapy to compensate for reduced 11β-HSD1 activity, although dose adjustment may be required in the longer term.

Free access

Is there a gender difference in the associations of birthweight and adult hypothalamic–pituitary–adrenal axis activity?

Rebecca M Reynolds, Brian R Walker, Holly E Syddall, Ruth Andrew, Peter J Wood and David I W Phillips

Objective: Increased hypothalamic–pituitary–adrenal (HPA) axis activity in men of low birthweight may be an important link between early life and the adult metabolic syndrome. In animal models females are more sensitive than males to HPA axis programming, but whether gender influences susceptibility in humans is unknown.

Design: Birth cohort study.

Methods: We studied 106 women aged 67–78 years, from Hertfordshire, UK, in whom birthweight was recorded. Negative feedback sensitivity was assessed by an overnight low-dose (0.25 mg) dexa-methasone suppression test, and adrenal sensitivity by a low-dose (1 μg) ACTH1 – 24 stimulation test. Cortisol and its metabolites were analysed in a 24 h urine collection. Data were compared with previously published identical measurements in 205 men aged 66–77 years from the same cohort.

Results: In women, plasma cortisol levels after dexamethasone were lower (P < 0.0001) and peak cortisol following ACTH1 – 24 were higher (P < 0.0001) than in men, suggesting a more responsive HPA axis. As in men, women with lower birthweight had enhanced plasma cortisol responses to ACTH1 – 24 (P = 0.05 for trend) but no difference in plasma cortisol after dexamethasone or in urinary cortisol metabolite excretion. The strength of the association in women was not different from that in men; a 1 lb decrease in birthweight was associated with an incremental rise in cortisol of 12.6 nmol/l (95% confidence interval (CI) 1.4, 23.8) in men, P = 0.03, and 14.8 nmol/l (95% CI −0.4, 29.9) in women, P = 0.05 (P = 0.82 for birthweight × gender interaction). In a combined analysis of men and women adjusted for gender (n = 302), a 1 lb decrease in birthweight was associated with a 13.4 nmol/l (95% CI 4.5, 22.4) greater incremental rise in plasma cortisol, P = 0.003.

Conclusions: Associations between lower birthweight and increased HPA axis activity are similar in men and women, supporting the hypothesis that HPA axis activation is an important mechanism underlying programming of adult disease.

Free access

Tissue-specific dysregulation of 11β-hydroxysteroid dehydrogenase type 1 in overweight/obese women with polycystic ovary syndrome compared with weight-matched controls

Alessandra Gambineri, Flaminia Fanelli, Federica Tomassoni, Alessandra Munarini, Uberto Pagotto, Ruth Andrew, Brian R Walker and Renato Pasquali

Context

Abnormal cortisol metabolism in polycystic ovary syndrome (PCOS) has been invoked as a cause of secondary activation of the hypothalamic–pituitary–adrenal axis and hence androgen excess. However, this is based on urinary excretion of cortisol metabolites, which cannot detect tissue-specific changes in metabolism and may be confounded by obesity.

Objective

To assess cortisol clearance and whole-body and tissue-specific activities of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1 (HSD11B1)) in PCOS.

Design

Case–control study.

Setting

Medical center.

Patients

A total of 20 overweight–obese unmedicated Caucasian women with PCOS, aged 18–45 years, and 20 Caucasian controls matched for age, BMI, body fat distribution, and HSD11B1 genotypes (rs846910 and rs12086634).

Main outcome measures

Cortisol metabolites were measured in 24 h urine. During steady-state 9,11,12,12-[2H]4-cortisol infusion, cortisol clearance was calculated and whole-body HSD11B1 activity was assessed as the rate of appearance of 9,12,12-2H3-cortisol (d3-cortisol). Hepatic HSD11B1 activity was quantified as the generation of plasma cortisol following an oral dose of cortisone. Subcutaneous adipose HSD11B1 activity and HSD11B1 mRNA were measured, ex vivo, in biopsies.

Results

Urinary cortisol metabolite excretion, deuterated cortisol clearance, and the rate of appearance of d3-cortisol did not differ between patients with PCOS and controls. However, hepatic HSD11B1 conversion of oral cortisone to cortisol was impaired (P<0.05), whereas subcutaneous abdominal adipose tissue HSD11B1 mRNA levels and activity were increased (P<0.05) in women with PCOS when compared with controls.

Conclusions

Tissue-specific dysregulation of HSD11B1 is a feature of PCOS, over and above obesity, whereas increased clearance of cortisol may result from obesity rather than PCOS.

Free access

A combination of polymorphisms in HSD11B1 associates with in vivo 11β-HSD1 activity and metabolic syndrome in women with and without polycystic ovary syndrome

Alessandra Gambineri, Federica Tomassoni, Alessandra Munarini, Roland H Stimson, Roberto Mioni, Uberto Pagotto, Karen E Chapman, Ruth Andrew, Vilma Mantovani, Renato Pasquali and Brian R Walker

Objective

Regeneration of cortisol by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) within liver and adipose tissue may be of pathophysiological importance in obesity and the metabolic syndrome. single nucleotide polymorphisms (SNPs) in HSD11B1, the gene encoding 11β-HSD1, have been associated with type 2 diabetes and hypertension in population-based cohort studies, and with hyperandrogenism in patients with the polycystic ovary syndrome (PCOS). However, the functional consequences of these SNPs for in vivo 11β-HSD1 expression and activity are unknown.

Methods

We explored associations of well-characterised hormonal and metabolic phenotypes with two common SNPs (rs846910 and rs12086634) in HSD11B1 in 600 women (300 with PCOS) and investigated 11β-HSD1 expression and activity in a nested study of 40 women from this cohort.

Results

HSD11B1 genotypes (as single SNPs and as the combination of the two minor allele SNPs) were not associated with PCOS. Women who were heterozygous for rs846910 A and homozygous for rs12086634 T (GA, TT genotype) had a higher risk of metabolic syndrome, regardless of the diagnosis of PCOS (odds ratio in the whole cohort=2.77 (95% confidence interval (CI) 1.16–6.67), P=0.023). In the nested cohort, women with the GA, TT genotype had higher HSD11B1 mRNA levels in adipose tissue, and higher rates of appearance of cortisol and d3-cortisol (16.1±0.7 nmol/min versus 12.1±1.1, P=0.044) during 9,11,12,12-2H4-cortisol (d4-cortisol) steady-state infusion.

Conclusions

We conclude that, in a population of Southern European Caucasian women with and without PCOS, alleles of HSD11B1 containing the two SNPs rs846910 A and rs12086634 T confer increased 11β-HSD1 expression and activity, which associates with the metabolic syndrome.