Inhibin secretion during the rat estrous cycle: relationships to FSH secretion and FSH beta subunit mRNA concentrations.
نویسندگان
چکیده
Serum inhibin and FSH and FSH beta subunit mRNA levels were measured at 3h intervals throughout the 4 day estrous cycle in female rats and hourly between 1000 and 2400 h of proestrus. On proestrus, serum inhibin concentrations fell during the late morning-early afternoon, then increased transiently during the late afternoon gonadotropin surges. Inhibin levels decreased during the late evening of proestrus, coincident with the FSH surge-related rise in FSH beta mRNA levels. Serum inhibin remained relatively stable during estrus and early metestrus, but rose during the late evening of metestrus and remained elevated until early diestrus. FSH beta mRNA levels were elevated on late estrus and early metestrus and declined during the evening of metestrus as serum inhibin levels increased. These data show that concentrations of serum inhibin change during the estrous cycle and that a general inverse relationship exists between serum inhibin and FSH levels and FSH beta mRNA concentrations in the pituitary. This suggests that inhibin may inhibit FSH beta gene expression and FSH secretion during the 4 day cycle in female rats.
منابع مشابه
Betaglycan localization in the female rat pituitary: implications for the regulation of follicle-stimulating hormone by inhibin.
Activin-stimulated FSH synthesis and secretion from the pituitary gonadotrope is negatively modulated by ovarian inhibin; however, the cellular mechanism of inhibin antagonism is unknown. Inhibin and activin share a common beta-subunit through which inhibin can compete with activin for binding to the activin type II receptor and prevent activin signal transduction. Although the affinity of inhi...
متن کاملPachytene spermatocytes in co-culture inhibit rat Sertoli cell synthesis of inhibin B-subunit and inhibin B but not the inhibin -subunit
This study investigates the effects of spermatogenic germ cells on inhibin -subunit and B-subunit expression, and inhibin -subunit and inhibin B production by rat Sertoli cells in vitro. Sertoli cells isolated from 19-day-old rats were cultured for 48 h at 32 C, in the presence or absence of FSH (2·3–2350 mIU/ml), and in the presence of pachytene spermatocytes, round spermatids or cytoplasts of...
متن کاملChanges in the reproductive functions of mice due to injection of a plasmid expressing an inhibin alpha-subunit into muscle: a transient transgenic model.
Inhibin is a gonadal hormone composed of an a-subunit and one of two beta-subunits (betaA, betaB), and its primary role is to inhibit FSH secretion by the pituitary. To investigate the roles of inhibin alpha in the reproductive system, an expression plasmid, pCMV-rINA, with the rat inhibin alpha cDNA fused to the cytomegalovirus promoter, was introduced into muscle by direct injection. Inhibin ...
متن کاملA mathematical model for the actions of activin, inhibin, and follistatin on pituitary gonadotrophs.
The timed secretion of the luteinizing hormone (LH) and follicle stimulating hormone (FSH) from pituitary gonadotrophs during the estrous cycle is crucial for normal reproductive functioning. The release of LH and FSH is stimulated by gonadotropin releasing hormone (GnRH) secreted by hypothalamic GnRH neurons. It is controlled by the frequency of the GnRH signal that varies during the estrous c...
متن کاملRegulations of gonadotropin secretion by circulating inhibin, estradiol, and progesterone in cyclic hamsters.
The physiological importance of gonadal hormones in feedback control of gonadotropin secretion during the estrous cycle in golden hamsters was investigated with immunoneutralization methods. Anti-inhibin serum (inhibin-AS) treatment always induced a drastic increase in follicle-stimulating hormone (FSH) secretion and occasionally raised luteinizing hormone (LH) secretion. Anti-estradiol-17β ser...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Life sciences
دوره 47 19 شماره
صفحات -
تاریخ انتشار 1990