Obesity in Osborne-Mendel and S 5B/Pl rats: effects of sucrose solutions, castration, and treatment with estradiol or insulin.
S 5B/Pl rats were tested for their susceptibility to develop obesity when 1) ovariectomized, 2) given injections of insulin, and 3) given a sucrose solution to drink instead of water. The results obtained in Osborne-Mendel rats susceptible to dietary obesity when fed a high-fat diet were compared to those obtained in the S 5B/Pl rats not susceptible to dietary obesity. When tested at the end of 10 wk, ovariectomized rats of both strains had gained 22% more weight than sham-operated controls. Replacement estradiol injections suppressed food intake in both strains with a concomitant loss in body weight. Osborne-Mendel rats tolerated at least 40 U of U-100 protamine zinc insulin/day and rapidly gained weight whereas S 5B/Pl rats given more than 2 U U-100 protamine zinc insulin/day died. Compared to female Osborne-Mendel rats drinking water, rats drinking a sucrose solution accumulated more body fat and had higher levels of serum immunoreactive insulin and lower levels of serum free fatty acids. The substitution of a sucrose solution for plain drinking water suppressed weight gain in S 5B/Pl rats.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002369:Castration; D004032:Diet; D004958:Estradiol / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D009765:Obesity / Q000209:etiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013395:Sucrose / Q000494:pharmacology*
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D004958:Estradiol; D013395:Sucrose