Fasted hypophysectomized (Hpx) rats (85-110 g) were utilized 3 or more weeks after the operation. Impairment of the oral glucose tolerance test (OGTT) was observed using a 15, 30 and 50% glucose (G) solution (1 ml/100 g bw). The impairment of the OGTT was greater with increased load of glucose. Neither 6, 18 or 24 hr of fasting, nor force feeding twice daily with 500 mg G in addition to the regular diet, altered the impairment in the OGTT when compared with control (C) rats. IVGTT (250 mg/100 g bw) also showed a significant impairment in the Hpx rats (p < 0.001). Bovine growth hormone (GH), 0.1 mg/rat/e.o. day, for 3 weeks, produced a normalization of the OGTT in the Hpx rats. Excess of GH (0.5 mg/rat/day) injected after operation for period of 2-7 days accelerated the onset of the impairment in the OGTT that appears regularly 3 weeks after operation. During the OGTT, the highest values of circulating insulin were significantly delayed in Hpx rats and the free fatty acids were significantly lower in the Hpx rats. Conclusion: The absence of the pituitary gland has a “diabetogenic” effect on the GTT. Paradoxically, an excessive amount of GH is also diabetogenic. (Endocrinology88: 1141, 1971)

This content is only available as a PDF.
You do not currently have access to this article.