Effects of Hypophysectomy and the Insulin-Like and Anti-Insulin Pituitary Peptides on Carbohydrate Metabolism in Yellow Avy/A (BALB/c × VY)F1 Hybrid Mice

AbstractThe amino-terminal portion of human growth hormone, residues 1–43 (hGH1–43), has insulin-potentiating action, while a hyperglycemic pituitary peptide (HP), which co-purifies with human growth hormone (hGH), is antagonistic to the action of insulin. The effects of hGH, hGH1–43, and HP on glucose metabolism were assessed in young (4–5 weeks) and adult (6–8 months) hypophysectomized yellow Avy/A mice which lacked any interfering endogenous pituitary hormones, and compared with age-matched intact obese yellow Avy/A and lean agouti A/a mice. Treatment with hGH1–43 or HP did not promote body growth in hypophysectomized yellow mice; but after 2 weeks of treatment with hGH, there was a significant increase in body weight (P < 0.05). Treatment with HP raised blood glucose and lowered insulin concentrations in obese yellow mice, but not in agouti or hypophysectomized yellow mice. The severely impaired glucose tolerance of the hypophysectomized yellow mice was improved by acute (60 min) and chronic (3 days) ...