Delayed onset of persistent estrus in aged rats raised from parathyroidectomized mothers

Ovarian carbonyl reductase delayed onset of persistent estrus in the offspring of parathyroidectomized mother rats

We investigated the effects of maternal parathyroidectomy on day 5 of pregnancy on the ovarian carbonyl reductase (CR) in the offspring of rats. Changes in the ovarian CR of the offspring were examined at 4 and 8 months of age. In 8-month-old female offspring, the ovarian weight and the ovarian CR activity were significantly higher in rats from parathyroidectomized mothers than in rats from sham-operated mothers, and the offspring of the parathyroidectomized mothers showed the regular 4-day estrous cycles at 8 months of age, while the offspring of the sham-operated mothers were in the state of persistent estrus. Furthermore, intense immunostaining was found in the theca interna cells and the interstitial gland cells in the ovary of rats from the parathyroidectomized mothers, whereas in the ovary of the age-matched normal rats, immunostaining was faint. These results suggest that the maternal parathyroidectomy affect the activity and localization of CR in the ovary of female offspring.

Blood pressure response to norepinephrine and angiotensin II in the offspring of parathyroidectomized mother rats

1. The basal blood pressure and the drug-stimulated pressor response were studied in male offspring in the sixth generation (5d-PTx-F6) of rats parathyroidectomized on day 5 of pregnancy. 2. The systolic blood pressure in conscious 5d-PTx-F6 rats measured by a tail cuff was significantly higher (P less than 0.001) than in control rats. 3. Venous plasma renin activity was significantly lower (P less than 0.001) in the 5d-PTx-F6 rats. Plasma levels of calcium, sodium, and potassium in the 5d-PTx-F6 rats and in the controls did not differ. 4. Systolic arterial pressure response to intravenously (i.v.) administered angiotensin II (150 ng/kg) in the 5d-PTx-F6 rats was significantly greater than in the controls (P less than 0.05), when blood pressure was measured directly through a pressure transducer under anaesthesia. 5. Pressor responses to norepinephrine (5 micrograms/kg, i.v.) in the 5d-PTx-F6 rats were significantly lower (P less than 0.05) than in the controls, when blood pressure was measured directly under anaesthesia. 6. The findings suggest that the 5d-PTx-F6 rats undergo functional alterations of the renin-angiotensin and sympathetic nervous systems for cardiovascular regulations.