Effects of neonatal growth on adult blood pressures of borderline hypertensive rats.
We conducted this study to test the hypothesis that there are long-term effects of litter-size manipulations during the preweaning period on growth and adult blood pressure of rats. Litter size of genetically homogeneous borderline hypertensive rats, which were produced by cross-mating male Wistar-Kyoto rats with female spontaneously hypertensive rats, was manipulated from 10 to 16 days of age. In addition, a subset of males and females was castrated within the first 30 hours of life. Body weights were measured at several preweaning and postweaning ages, and tail-cuff blood pressures were recorded at 90 days of age. Intact and castrated pups of both sexes that were reared in small (n = 4) litters from 10 to 16 days of age gained nearly twice the weight of animals reared in large (n = 9 to 12) litters during this period. Intact males from small litters had significantly higher adult blood pressures than those from large litters. These long-term effects remained even in groups matched for adult weight and length. Neonatal castration of males completely blocked the consequences of litter-size manipulation on adult blood pressure, suggesting either an organizational or activational role for androgens. Neither intact nor neonatally castrated females exhibited differences in adult blood pressure as a function of litter-size manipulation.
Myers
M M
MM
Department of Psychiatry, College of Physicians and Surgeons of Columbia University, New York, NY, USA.
Handler-Matasar
S R
SR
Shair
H N
HN
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development*; D001794:Blood Pressure; D001835:Body Weight; D002369:Castration; D005260:Female; D006824:Hybridization, Genetic; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012727:Sex Characteristics