Effect of hypertension on reproductive organ weights in various strains of rats

The testes of Wistar Kyoto (WKY) and Spontaneously Hypertensive (SHR) rats have been shown to have differences in regional vascular resistance. In addition, myocardial hypertrophy tends to be more pronounced and occur more frequently in WKY and SHR female rats than in their male counterparts. Therefore, we sought to determine whether hypertension had any effect on reproductive organs and whether this effect was the same among strains. We removed the testes or uterus from Sprague Dawley (SD; n = 30 male and 30 female), WKY (n = 23 male and 16 female), and SHR (n = 27 male and 34 female) rats, weighed these animals and organs, and calculated the reproductive organ:body weight ratio (mean +/- 1 standard deviation x 10-3 g). The testes:body weight ratio of WKY (6.5 +/- 0.8) animals was significantly (P= 0.05) less than those of SD (7.6 +/- 1.1) and SHR (8.0 +/- 0.5) rats. The uterus:body weight ratio of the SD rats (1.7 +/- 0.4) was significantly (P = 0.05) less than those of WKY (2.4 +/- 0.6) and SHR (2.3 +/- 0.6) rats. Compared with WKY rats, male SD rats had a higher testes:body weight ratio whereas female SD rats had a lower uterus: body weight ratio. Whereas the SHR testes:body weight ratio was significantly higher than that of WKY rats, this effect was not seen for the uterus: body weight ratio. The effect of hypertension on reproductive organs should be taken into consideration when choosing a species, gender, or organ for study. As well, data compared across genders or strains must be evaluated carefully to ensure valid comparisons.