Summary: Multiple research studies address the anti-insulinemic effect of growth hormone (GH). We report a case of a patient with anterior hypopituitarism on GH replacement who later developed type 1 diabetes mellitus (T1DM). Recombinant human growth hormone (rhGH) therapy was discontinued at the time of growth completion. Because of significantly improved glycemic control, this patient was weaned off subcutaneous insulin. He regressed from stage 3 to stage 2 T1DM and remained in this status for at least 2 years and until the writing of this paper. The diagnosis of T1DM was established based on relatively low C-peptide and insulin levels for the degree of hyperglycemia as well as seropositivity of zinc transporter antibody and islet antigen-2 antibody. Additional laboratory data obtained 2 months after discontinuing rhGH revealed improved endogenous insulin secretion. This case report calls attention to the diabetogenic effect of GH therapy in the setting of T1DM. It also demonstrates the possibility of regression from stage 3 T1DM requiring insulin therapy to stage 2 T1DM with asymptomatic dysglycemia after discontinuing rhGH.

Learning points: Given the diabetogenic effect of growth hormone, blood glucose levels should be monitored in patients with type 1 diabetes mellitus (T1DM) on insulin therapy and recombinant human growth hormone (rhGH) replacement. Clinicians should closely monitor for risk of hypoglycemia after discontinuing rhGH among T1DM patients who are on insulin treatment. The discontinuation of rhGH in the setting of T1DM may cause regression of symptomatic T1DM to asymptomatic dysglycemia requiring no insulin treatment.