The effect of alloxan-induced diabetes on triamine lesions in the ventromedial hypothalamus.

It has been demonstrated that the ventromedial hypothalamus (VMH) of alloxan-induced diabetic mice is protected from subsequent gold thioglucose (GTG)-induced lesions. Another compound, 3,3'-methyliminobis-(N-methylpropylamine) (MIMPA), a triamine structurally unrelated to GTG, has been shown to cause similar VMH lesions in mice. We chose to investigate the effect of alloxan-induced diabetes on VMH lesion formation in MIMPA-treated mice. In this study CF-1 female mice were made diabetic by a simple intravenous (IV) injection of alloxan and subsequently treated with MIMPA by subcutaneous injection (SC). Contrary to studies which showed that GTG-induced VMH lesions are insulin dependent, an insulin deficiency did not inhibit MIMPA-induced lesions in the VMH of mice. Our data suggests, albeit GTG is suspected to induce VMH necrosis by attaching to glucoreceptors and insulin-sensitive neurons, MIMPA works by a different and as yet unknown mechanism. We conclude that MIMPA-induced lesions in the VMH of mice are not insulin dependent.

Beta-thioglucose inhibits gold thioglucose lesions in the ventromedial hypothalamus.

Gold thioglucose (GTG) has been known to be an obesity causing agent for over 40 years. GTG works by affecting dendrites in the mouse ventromedial hypothalamus (VMH) producing a permanent VMH lesion and subsequent hyperphagia and obesity. We have investigated the effect of beta-thioglucose (BTG), a glucose antimetabolite, on GTG-induced lesions in the VMH of mice. Twenty-eight female CF-1 mice were used in this study. Seven micron sections were made of the mouse VMH, mounted on glass slides, and stained with hematoxylin and eosin. A previous report of BTG action on GTG-induced lesions has not supported a competitive inhibition between these two drugs. Our data demonstrate that at 1/2 hour, 6 hours, and 12 hours post BTG, BTG completely inhibited GTG-induced lesions in the VMH.