Preweanling rats: recovery from lateral hypothalamic damage.

Preweanling male and female albino rats sustained lateral hypothalamic area (LHA) destruction at 10 days of age. Pups with bilateral LHA destruction (Bi-LHA) displayed the lateral hypothalamic recovery syndrome (LHRS) and recovered voluntary feeding and drinking between 44-75 days of age. The Bi-LHA rats of both sexes showed permanent deficits (through 200-275 days of age) in responding to hydrational challenges and did not feed in response to 2-deoxy-D-glucose treatment. Male Bi-LHA rats' body weights were permanently depressed by 20%-25%, whereas female body weight depression was only temporary. Rats sustaining LHA destruction on one side of the brain (Uni-LHA) displayed an abbreviated LHRS, recovering voluntary feeding and drinking by 25-32 days of age. The Uni-LHA rats showed some permanent deficits in responding to hydrational challenges, yet they displayed the same sex differential for body weight regulation as the Bi-LHA rats. The results of this investigation demonstrate nearly identical effects of LHA destruction whether sustained preweaning, postweaning, or during adulthood.