SERUM AND PITUITARY LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE AND PROLACTIN LEVELS IN GONADECTOMIZED MALE, FEMALE AND ANDROGENIZED FEMALE RATS TREATED WITH OESTRADIOL BENZOATE

Abstract

SUMMARY: Changes in serum concentrations and pituitary content of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin, determined by radioimmunoassay, were studied after oestradiol benzoate (OEB) administration to gonadectomized male and female rats and to gonadectomized females androgenized with 50 μg testosterone propionate on the 5th day post-partum. Oestradiol benzoate (0·05–50 μg) was given once a day for 7 days beginning 3 weeks after removal of the gonads. A rise in serum LH concentration was produced by 0·05 μg OEB in all animals, but a reduction was found with the larger doses. Serum FSH increased in females injected with 0·05 μg OEB, but males and androgenized females had decreased FSH levels with all doses. The prolactin concentrations increased in the sera of all animals treated with 0·05 μg or 0·5 μg oestrogen. Males showed no further increases with larger doses. A very large increase was found in females given 5 μg but 50 μg did not have this stimulatory effect. Dose-dependent increases in serum prolactin were noted in androgenized females. Pituitary prolactin content increased in females and androgenized females treated with oestrogen; a slight, but significant, increase was found only in the males given 50 μg. Pituitary LH was increased only in the animals receiving a large amount of oestrogen (5 or 50 μg). Glandular FSH increased in the males and androgenized females given 0·5 μg OEB, but in all animals a reduction in this gonadotrophin was found after giving 50 μg of the oestrogen. The results indicate that androgenization alters the normal female hypothalamo-hypophysial response to oestrogen but it does not induce the response pattern of the male.