Effects of parathyroidectomy in pregnant rats on the luteinizing hormone and follicle-stimulating hormone response to synthetic luteinizing hormone-releasing hormone in the infantile offspring.

Abstract

Effects of parathyroidectomy (PTx) in the rat at the 5th day of gestation on the functional development of gonadotrophin secretion in the infantile offspring was examined. A single subcutaneous injection of 10 micrograms/kg of luteinizing hormone-releasing hormone (LHRH) induced a significant increase in serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) in control- and PTx-F1 male and female rats already at 3 days of age. The response in female rats was greater than in males at all ages examined. In the control- and PTx-F1 rats, age-related increase in the responsiveness to LHRH was observed in both sexes for LH but only in females for FSH. However, LH and FSH release by LHRH in the PTx-F1 female rats was significantly lower than that in control females at 14 and 22 days of age. In the PTx-F1 male rats, only FSH response to LHRH showed a tendency to decrease at 22 days of age. Serum calcium levels in 3-day-old PTx-F1 male and female rats were significantly lower than those in controls but only a slight decrease was observed in the PTx-F1 rats at other ages. The present results indicated that a low serum calcium environment during fetal life in the rat affects the functional development of pituitary responsiveness to LHRH, particularly in females.