Propionate Tolerance Test for Determination of Insulin Secretion in a Hyperglycemic japanese Black Steer

Abstract

ABSTRACT. A propionate tolerance test (PTT) was used to determine the pathophysiology of a Japanese Black steer with hyperglycemia. In the hyperglycemic steer, a low insulin secretion was confirmed by a glucose tolerance test (GTT), so that the hyperglycemic steer was diagnosed as insulin-dependent diabetes mellitus. Although the plasma insulin concentration in the control cattle increased in response to propionate stimulation, a low insulin response to PTT was observed in the diabetic steer. The fact that both PTT and GTT determined that the diabetic steer had low insulin secretion suggests that the PTT might be an effective diagnostic tool for diabetes mellitus in cattle. KEY WORDS: cattle, diabetes mellitus, propionate tolerance test.J. Vet. Med. Sci. 69(9): 985-987, 2007 Diabetes mellitus is uncommon in cattle whose blood glucose concentration is regulated within a narrow range. Although there are a few individual reports of diabetes mellitus in cattle [1][2][3][4][7][8][9], most of them deal mainly with histopathological findings of diabetic cattle [11][12][13][14]. Therefore, only a few clinical features of diabetes mellitus in cattle have been clarified. To determine the pathophysiology of diabetes mellitus, the intravenous glucose tolerance test (GTT) is commonly carried out in cattle as well as other animals, and diabetes mellitus is classified as either insulindependent or non-insulin dependent [5,6]. In ruminants, the blood glucose concentration is maintained at a stable level, because it is regulated by fermentation in the rumen and by gluconeogenesis from volatile fatty acids in the liver. Therefore, cattle are poorly adapted to hyperglycemia, and hyperglycemia caused by GTT might induce metabolic abnormality in diabetic cattle to make their condition worse. Since glucose metabolism in ruminants is quite different from that in monogastric animals, an alternative method of diagnosis of diabetes mellitus in cattle seemed to be needed. In this report, we conducted a propionate tolerance test (PTT) to determine the pathophysiology of a hyperglycemic steer, because propionate injection is known to directly stimulate insulin secretion and to be a major glycogenic substrate for ruminants [10].A one-year-old Japanese Black steer, weighing 220 kg and in an emaciated condition, was presented with a 2-month history of chronic serous diarrhea, weight loss, dehydration, and depression. Its rectal temperature, heart rate, and respiratory rate were 39.4°C, 65 beats/min, and 18 breaths/min, respectively, and they were considered normal. The steer's water intake increased, and the frequency and strength of its rumen contractions decreased. The steer demonstrated neither the abnormal behavior associated with neurologic manifestations nor the posture peculiar to abdominal pain.A routine hematological examination, including a complete blood count and blood biochemistry, was performed using an automatic analyzer (Celltac, MEK-5258, Nihon Kohden, Tokyo, Japan, and FDC 3500V, Fuji Medical Systems, Tokyo, Japan). The st...

Pre- and postnatal nutrition in sheep affects β-cell secretion and hypothalamic control

“…Propionate has been shown to be an insulin secretagogue in addition to glucose (Sano et al 1993), and it is likely that the high-fat diet, in general, reduced b-cell responsiveness to major secretagogues such as glucose and propionate. Interestingly, propionate has also been used as a diagnostic tool in ruminants to identify diabetic animals (Takasu et al 2007), where a reduced insulin response was observed just as we had observed in the present study. The reduced b-cell responsiveness would also be an important factor explaining why the HCHF lambs even 2 h after injection continued to have markedly elevated glucose concentrations compared with the NORM lambs.…”

Positive correlations of age and parity with plasma concentration of macrophage migration inhibitory factor in Japanese black cows

“…The limit of detection was 0.025 ng/ml and the intra- and inter-assay CVs were 3.3% and 8.7%, respectively, at 0.50 ng/ml. This assay has been used to measure changes in blood insulin concentrations in Japanese Black steer before and after glucose treatment [ 22 ].…”