Study to Determine the Effects of Human Growth Hormone and Pioglitazone in Overweight, Prediabetic Adults

Effects of GH and Pioglitazone in Viscerally Obese Adults With IGT

The purpose of the study was to determine the effects of growth hormone and an insulin sensitizer drug in pre-diabetic adults with excessive amounts of abdominal fat. Participants received a combination of two drugs: (1) recombinant human growth hormone (or its placebo) and (2) pioglitazone (or its placebo). We measured the abdominal fat content and blood sugar levels of participants before and after 40 weeks of treatment.

Treatment with recombinant human growth hormone (GH) has been shown to reduce visceral adipose tissue (VAT) and improve insulin sensitivity in normoglycemic adults, but glucose levels may rise transiently. Pioglitazone, a thiazolidinedione (TZD) drug, counters the short-term diabetogenic effect of GH in rodents, but combined use of these drugs has not been evaluated in humans.

The purpose of this study was to determine the effects of GH and a TZD, alone and in combination, on glucose metabolism, visceral adiposity and insulin sensitivity in abdominally obese adults with impaired glucose tolerance. The hypothesis that combined treatment attenuates GH-induced increases in glucose concentrations, reduces VAT, and improves insulin sensitivity over time was tested. Sixty-two adults received GH and pioglitazone for 40 weeks in a double-blind, randomized, placebo-controlled trial.

Inclusion Criteria:

• Age between 40 and 75 years
• BMI > 27 kg/m2
• Waist circumference >100 cm for men and > 88 cm for women
• Impaired glucose tolerance (documented by a 75 gram OGTT)

Exclusion Criteria:

• Diabetes mellitus
• Malignancy
• Premenopausal women who are breastfeeding or decline contraception
• Congestive heart failure
• ALT > 3 times upper normal limit