Mechanism of reproductive deficiency in spontaneously hypertensive rats.
Spontaneously hypertensive rats (SHR) show multiple endocrine disorders. In the present work, specific reproductive modifications were analysed using normotensive Wistar-Kyoto rats (WKY) as controls. SHR showed delayed vaginal opening and first estrus presentation, regular vaginal cycles and released a normal number of ova each cycle. When compared with controls, SHR showed a decrease in the percentage of successful pregnancies (69% vs. 86% in WKY) and in the litter size (7.83 +/- 0.5 vs. 10.41 +/- 0.5). In SHR, progesterone plasma levels were significantly increased during the days 1-14 of pregnancy, and on the 5th day of pregnancy the plasma concentrations of LH but not of FSH were enhanced. Mortality during the first month of life was higher in SH (50%) than in control (24%) strain. When the SH females were mated with Wistar or WKY males, the percentage of pregnancies rose up to 95%. On the contrary, Wistar or WKY females mated with SH males showed a decrease in the percentage of pregnancies (62.5% and 50%, respectively). Besides, the litter sizes were significantly reduced in Wistar females mated with SH males. Newborn SH suckled immediately after birth from a WKY mother showed a significant reduction in the mortality during the first month of life (8% vs. 50%). In conclusion, our results suggest that changes in fertilization and/or implantation processes of SH rats were responsible for the reduced pregnancy rate, whereas the increased neonatal mortality could be due to lactation activity of SH mothers.
Pinilla
L
L
Department of Physiology, Faculty of Medicine, Cordoba University, Spain.
Rodriguez-Padilla
M L
ML
Sanchez-Criado
J
J
Gaytan
F
F
Aguilar
E
E
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000502:physiology; D008098:Litter Size / Q000502:physiology*; D008297:Male; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D011374:Progesterone / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012733:Sex Differentiation / Q000502:physiology; D013091:Spermatogenesis / Q000502:physiology
D011374:Progesterone; D005640:Follicle Stimulating Hormone