This review will summarize the properties of five variant forms of human growth hormone: a disulfide dimer, a glycosylated form, 20 KD-hGH, and two peptides made up of portions of 22 KD-hGH. The two pituitary peptides (hGH_1-43 and hGH_44-191) have, respectively, insulin-potentiating and anti-insulin properties. Both have been detected in serum. The shorter peptide may prove to be useful in decreasing the amount of exogenous insulin required by diabetics. The larger, strongly anti-insulin peptide, may be involved in diabetic retinopathy. We believe that this peptide is the long sought after diabetogenic substance of the pituitary gland.