Circulating reproductive hormones and hypothalamic oestradiol and progestin receptors in infertile Zucker rats.
Plasma concentrations of LH, FSH, prolactin and progesterone were measured during the oestrous cycle in obese (fa/fa) and non obese (Fa/?) Zucker rats. In obese rats the mid-afternoon surge of LH during prooestrus was reduced compared with that in non-obese rats (P less than 0.05), and the maximum concentrations of FSH and prolactin declined more slowly during oestrus. Progesterone concentrations were higher during most of the oestrous cycle in obese rats. Oestradiol and progestin receptors were measured in the hypothalamus of female Zucker rats. Lower concentrations of oestradiol receptors were found in the preoptic area of obese rats (P less than 0.05). Concentrations of oestradiol receptors in the medial basal hypothalamus were also lower in obese rats, though the difference was not statistically significant. Concentrations of progestin receptors were similar in both phenotypes in the preoptic area and media basal hypothalamus. It seems likely that the abnormalities in reproductive hormones and oestradiol receptors contribute to the infertility of obese female Zucker rats. The underlying mechanism has still to be determined.
Whitaker
E M
EM
Department of Physiology, University of Leeds.
Robinson
A C
AC
D000818:Animals; D004971:Estrus / Q000502:physiology; D005260:Female; D006065:Gonadotropins, Pituitary / Q000097:blood*; D007031:Hypothalamus / Q000032:analysis*; D007246:Infertility / Q000503:physiopathology; D009765:Obesity / Q000503:physiopathology; D011374:Progesterone / Q000097:blood*; D051381:Rats; D011924:Rats, Zucker; D011980:Receptors, Progesterone / Q000032:analysis*; D011981:Receptors, Prolactin / Q000032:analysis*; D013997:Time Factors
D006065:Gonadotropins, Pituitary; D011980:Receptors, Progesterone; D011981:Receptors, Prolactin; D011374:Progesterone