The aim of this paper is to elucidate the cause of death after 90 min of normothermic partial (2/3) ischemia of the liver and to examine the effects of glucagon, somatostatin, insulin, prednisolone and oral administration of polymyxin B (PB). The animals 24 hr after partial ischemia for 90 min were divided into two groups; namely, animals with normal appearance and those with moribund state. There were no significant differences in the plasma level of S-GOT, S-GPT, amino acids, NH3 or insulin, or in morphometrically estimated volume ratio of necrotic hepatocytes between the two groups of rats. The blood glucose level, however, was significantly decreased (31 +/- 28 mg/100 ml, n = 6) in the moribund rats with a higher incidence of positive Limulus gelation tests as compared with the rats with normal appearance (149 +/- 19, n = 5). The 1-day and 1-week survival rates of the animals were 42/62 (69%) and 32/61 (53%), respectively. A glucagon injection (1.5 mg/kg, after ischemia) was effective to elevate the 1-day survival rate (14/14), but failed to increase the 1-week survival rate (11/14). On the other hand, a somatostatin injection (100 micrograms/kg, after ischemia) or PB treatment (15 mg/kg/day x 5-9, before ischemia) succeeded to increase the 1-week survival rate (20/22 p less than 0.01 and 17/17 p less than 0.01, respectively), although no significant amelioration in transaminase levels or volume ratio of necrosis was demonstrated. It could be seen that a moribund state after partial ischemia was accompanied by severe hypoglycemic shock, and that the injection of somatostatin after ischemia or the annihilation of gram-negative bacteria by means of oral administration of polymyxin B before ischemia prevented the occurrence of the hypoglycemic shock.