EurekaMag.com logo
+ Translate

Regulation of gonadotropin release by luteinizing hormone-releasing hormone and estrogen in chimpanzees


, : Regulation of gonadotropin release by luteinizing hormone-releasing hormone and estrogen in chimpanzees. Endocrinology 105(1): 269-275

Plasma LH [luteinizing hormone] and FSH [follicle stimulating hormone] levels were determined by RIA [radioimmunoassay] before and after an i.v. bolus of LHRH [luteinizing hormone releasing hormone] in adult female chimpanzees. The pre-LHRH concentration of 17.beta.-estradiol (E2) was determined by RIA. Menstruating and postpartum chimpanzees (mean E2, 29.8 and 45.0 pg/ml, respectively) showed a monophasic LH response characterized by a 2- to 3-fold increase in LH levels within 15 min of LHRH injection, followed by a slow decline. In animals which had elevated estrogen levels, namely midfollicular animals (mean E2, 73.6 pg/ml), menstruating animals pretreated with 5 .mu.g estradiol benzoate for 2 days (mean E2, 283.2 pg/ml), and postpartum chimpanzees administered 50 .mu.g mestranol/day for 7 days, LH showed a reduced or similar initial rise, followed by a plateau or slight decline during the first 60 min after LHRH but, thereafter, a progressive secondary increase that continued throughout the second 60 min. This secondary augmentation was greatly exaggerated when a long acting LHRH analog (desGly10-[D-Trp6, Pro9, NEt[ethylamide]]LHRH) was administered. FSH responses were inhibited during the first 2 h when estrogen levels were elevated, except in animals administered the long acting analog which showed a secondary augmentation of FSH after 3 h. The relative gonadotropin increment after LHRH administration in the chimpanzee is similar to the human; estrogen can differentially modulate the LH and FSH responses to LHRH, partly by preferential augmentation of LH release, as seen in this study 1 h after LHRH challenge.

(PDF same-day service: $19.90)

Accession: 041210819

PMID: 376298

DOI: 10.1210/endo-105-1-269

Submit PDF Full Text: Here


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Graham C.E.; Gould K.G.; Collins D.C.; Preedy J.R.K., 1979: Regulation of gonadotropin release by luteinizing hormone releasing hormone and estrogen in chimpanzees pan troglodytes. Plasma LH [luteinizing hormone] and FSH [follicle stimulating hormone] levels were determined by RIA [radioimmunoassay] before and after an i.v. bolus of LHRH [luteinizing hormone releasing hormone] in adult female chimpanzees. The pre-LHRH concen...

Gosselin R.E.; Hobson W.C.; Vale W., 1979: Inhibition of luteinizing hormone releasing hormone or estrogen induced gonadotropin surges by luteinizing hormone releasing hormone analog in chimpanzees. Biology of Reproduction 20(SUPPL 1): 109A

Glass, M.R.; Shaw, R.W.; Williams, J.W.; Butt, W.R.; Logan-Edwards, R.; London, D.R., 1976: The control of gonadotropin release in women with hyper prolactinemic amenorrhea effect of estrogen and progesterone on the luteinizing hormone and follicle stimulating hormone response to luteinizing hormone releasing hormone. The effect of the administration of estradiol benzoate and of progesterone on the subsequent response to LHRH [luteinizing hormone-releasing hormone] was investigated in women with hyperprolactinemia. There was an amplification in the release of L...

Irvin, H.J.; Zaied, A.A.; Day, B.N.; Garverick, H.A., 1981: Gonadotropin releasing hormone induced luteinizing hormone release in suckled beef cows 1. the effects of days post partum and estradiol 17 beta concentrations on the release of luteinizing hormone following administration of gonadotropin releasing hormone. Twenty suckled Charlois .times. Hereford beef cows (5 cows/group) were assigned at random to receive 100 .mu.g GnRH [gonadotropin releasing hormone] i.m. at either 2-3, 7-8, 15-16 or 31-32 days postpartum, groups 1 through 4, respectively. Blood s...

Irvin, H.J.; Pflantz, V.M.; Morrow, R.E.; Day, B.N.; Garverick, H.A., 1981: Gonadotropin releasing hormone induced luteinizing hormone release in suckled beef cows 2. the effects of exogenous corticoids and estradiol benzoate on luteinizing hormone release by gonadotropin releasing hormone. In experiment I, 24 suckled beef cows were assigned to 4 treatment groups (6 cows/group). Group I cows calved spontaneously. Parturition was induced in Groups 2, 3 and 4 with 20 mg dexamethasone (DEX) 8-12 days prior to expected calving date. Addi...

Petersen, S.L.; Cheuk, C.; Hartman, R.D.; Barraclough, C.A., 1989: Medial preoptic microimplants of the antiestrogen, keoxifene, affect luteinizing hormone-releasing hormone mRNA levels, median eminence luteinizing hormone-releasing hormone concentrations and luteinizing hormone release in ovariectomized, estrogen-treated rats. Abstract We examined the temporal changes in plasma luteinizing hormone (LH) levels, median eminence luteinizing hormone-releasing hormone (LHRH) concentrations and LHRH mRNA levels in estrogen-treated, ovariectomized rats with empty or antiestrog...

Jackson, G.L., 1975: Blockage of estrogen-induced release of luteinizing hormone by reserpine and potentiation of synthetic gonadotropin-releasing hormone-induced release of luteinizing hormone by estrogen in the ovariectomized ewe. These experiments tested the effects of reserpine on estrogen-induced LH release and the effects of estrogen on gonadotropin-releasing hormone-induced LH release in ovariectomized ewes. Injection of 50, 200, or 500 mug of estradiol benzoate (EB) i...

Jackson, Gl, 1975: Bolockage of estrogen-induced release of luteinizing hormone by reserpine and potentiation of synthetic gonadotropin-releasing hormone-induced release of luteinizing hormone by estrogen in the ovariectomized ewe. Endocrinology 97 (5) 1300-1307

De-Koning, J.; Van-Dieten, J.A.M.J.; Van-Rees, G.P., 1977: Effect of pre incubation with different concentrations of luteinizing hormone releasing hormone on subsequent luteinizing hormone release caused by supramaximally active amounts of luteinizing hormone releasing hormone role of luteinizing hormone releasing hormone induced protein synthesis. Anterior pituitary glands from intact diestrous female rats were incubated for 2 consecutive periods of 3 h. During the 1st period various submaximally active amounts of luteinizing hormone-releasing hormone (LH-RH) were added to the media, wherea...

Hobson, W.; Fuller, G.B., 1977: Luteinizing hormone releasing hormone induced gonadotropin release in chimpanzees. The ability of LH-RH (125 .mu.g i.v.) to induce LH [luteinizing hormone] and FSH [follicle-stimulating hormone] release was studied in 5 male and 11 female adult chimpanzees. LH peaks were found after LH-RH [LH-releasing hormone] treatment in all...