Plasma and pituitary concentrations of LH, FSH and prolactin in aged female C57BL/6 mice.
Plasma and pituitary concentrations of LH, FSH and prolactin were determined by radioimmunoassay in 2-month-old (young) and 16-20-month-old (old) C56BL/6 mice. There were no statistical differences in hormonal levels between aged females in oestrus (those exhibiting a copulatory plug) and those in constant dioestrus. In the old females plasma levels of LH (P < 0.002) and FSH (P < 0.001) were significantly elevated, while levels of prolactin (P < 0.001) were significantly depressed when compared with those from young animals. Pituitary homogenates from old females also contained more gonadotrophins (P < 0.001) and less prolactin (P < 0.001) than those of the young females. A radioreceptor assay utilizing a plasma membrane of luteinized rat or mouse ovaries indicated that LH from 2-month-old animals bound better to ovarian receptors (P < 0.05) than did LH from old mice, although radioimmunoassay of the same samples gave higher (P < 0.01) plasma LH levels for the old mice. Since the radioreceptor assay is considered to be a more sensitive test for biologically active LH, the results from these two types of assays suggest that there may be an alteration in the mouse LH molecule with age.
D000375:Aging; D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010902:Pituitary Gland / Q000378:metabolism*; D011388:Prolactin / Q000097:blood / Q000378:metabolism*
D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone