Experimental induction of fasting hypoglycaemia and fatty liver syndrome in three Yorkshire terrier pups.

Eight hours fasting in Yorkshire terrier pups resulted in marked variation of blood glucose, showing both hypo- en hyperglycaemia. Prolonged fasting in three Yorkshire terrier pups resulted in hypoglycaemia with concomitant ketosis and steatosis of the liver. The hypoglycaemia was associated with decreasing insulin and increasing glucagon and cortisol levels. This is in contrast to fasting adult dogs, which maintain glucohomeostasis and show only slightly decreased insulin levels, normal glucagon levels and a moderate increase of plasma ketone bodies. The reaction to an eight hour fasting period in the Yorkshire terrier pups is thought to be related to inadequate gluconeogenesis and diminished insulin production and/or release. The different reaction to prolonged fasting, compared to adult dogs and pups of larger breeds, seems related to inadequate gluconeogenesis and results in hypoglycaemia, a ketogenic hormonal setting and steatosis of the liver. Frequent feeding of a high-energy, protein-rich diet to both mother and pups may prevent toy-breed pups from developing hypoglycaemia and may help them to overcome periods with a decreased intake of energy.