Effect of glucose load and of insulin on the metabolism of glucose and of palmitate in sheep

Abstract

1. Simultaneous measurements of the entry rates of palmitate and glucose have been made in Merino sheep (wethers), starved for 24hr., by using constant infusions of [9,10-(3)H(2)]palmitate and [U-(14)C]glucose. 2. The infusion of glucose into the peripheral circulation of the sheep lowered the endogenous entry of both glucose and palmitate. Since palmitate is roughly metabolically representative of the free fatty acid fraction, there was no marked change in the calories available to the sheep. 3. The infusion of insulin into either the peripheral or portal circulation increased the uptake of glucose and decreased the uptake of palmitate by the tissues of the sheep. 4. The infusion of insulin into the peripheral circulation produced a depression in glucose entry after about 80min., whereas the infusion of insulin into the portal circulation produced an almost immediate depression in glucose entry. 5. The hypoglycaemia produced gave rise to an increase in free fatty acid production followed by an increase in glucose production. 6. No direct effect of insulin on the metabolism of free fatty acids has been demonstrated by the techniques used. The effect of insulin on the metabolism of free fatty acids is apparently mediated through its effect on glucose metabolism.

Effects of feeding dry propylene glycol to early postpartum Holstein dairy cows on production and blood parameters

“…to an increase in blood propionate concentration from microbial degradation of PG in the rumen (Kristensen and Raun, 2007) and/or (ii) an increase in tissue affinity for BHBA induced by PG directly or via endogenous metabolites (Kristensen et al, 2002). Insulin is a potent antilipolytic factor which reduces lipolysis in adipose tissue, thereby, reducing the release of NEFA from adipocytes to the liver (West and Passey, 1967). Kronfeld (1965) demonstrated that by intravenously injecting insulin, plasma NEFA levels were decreased in milking dairy cows.…”

Untersuchungen zum Glucosestoffwechsel von Schafen bei verschiedenen Reproduktionsstadien und bei Ketose mit Hilfe des intravenösen Glucose‐Toleranz‐Tests (IVGTT)

“…KONIG, 1985) lag. Nach dem Glucosebelastungstest wurden die Tiere taglich mit 80 g einer Mineraldiat (Korvimin@), 25g Na-Propionat, 25g Ca-Lactat und 12g KC1 ad 0, 51 Bei dem derzeit unbefriedigenden Kenntnisstand iiber den Pathomechanismus der Schafketose sollte die Therapie zunachst auf langfristige Anregung der Futteraufnahme und Pansenaktivitat sowie auf eine Unterstutzung der Glucostase-Regulation durch Glucosevorlaufer-Substitution gerichtet sein. Tagliche orale Behandlung mit einer Mischung von 80 g einer wiederkauergerechten Mineraldiat (Korviminm), 25 g Na-Propionat, 25 g Ca-Lactat und 12 g KCI ad 0,5 1 Wasser bei freier Wasseraufnahme (und Heuangebot) bis zur klinischen Besserung war bei 26 von 41 erkrankten Tieren erfolgreich (63 "A), wahrend die vorher angewandte Therapie auf der Basis taglicher intravenoser Glucosesubstitution nur bei 32 von 60 Tieren (53 "/ . )…”

Effects of feeding maize or lucerne on blood metabolites, plasma insulin, and pancreatic insulin concentrations in lambs

“…The association between the increased blood glucose concentrations and elevated plasma insulin levels in the lambs fed maize is consistent with insulin having a role in maintaining glucose homeostasis by stimulating the peripheral utilisation of glucose (West & Passey 1967;Jarrett et al 1972). This concept is supported by the findings that the lambs fed maize cleared exogenous glucose in the glucose tolerance test faster than the lambs fed lucerne.…”