scholarly journals PROGESTERONE BLOCKADE OF ESTROGEN-INDUCED LH RELEASE IN ANESTRUAL EWES

1978 ◽  
Vol 58 (2) ◽  
pp. 329-331 ◽  
Author(s):  
B. E. HOWLAND ◽  
L. M. SANFORD ◽  
W. M. PALMER
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Lh Release ◽  
Stimulating Hormone

A release of luteinizing hormone (LH) was induced in anestrual ewes following an injection of 50 μg or 1 mg estradiol-17 β (E2). Daily injections of 30 mg progesterone, ending 4 h before estrogen, were completely effective in blocking the induced LH release if begun at least 1 day before 50 μg E2 or 3 days before 1 mg E 2. Ewes releasing LH had an accompanying release of follicle-stimulating hormone.

LEVELS OF FOLLICLE-STIMULATING HORMONE, LUTEINIZING HORMONE, OESTRADIOL-17β AND PROGESTERONE, AND FOLLICULAR GROWTH IN THE PSEUDOPREGNANT RAT

1975 ◽  
Vol 64 (1) ◽  
pp. 37-47 ◽  
Author(s):  
R. WELSCHEN ◽  
P. OSMAN ◽  
J. DULLAART ◽  
W. J. DE GREEF ◽  
J. TH. J. UILENBROEK ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Blood Levels ◽  
Normal Cycle ◽  
Antral Follicles ◽  
A Value ◽  
Wide Range ◽  
Lh Release ◽  
Competitive Protein Binding ◽  
Stimulating Hormone

SUMMARY Throughout a period of pseudopregnancy the peripheral blood levels of progesterone, oestradiol-17β, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), as well as the size-distribution of ovarian antral follicles were estimated in the rat. The progesterone concentrations, as measured by a competitive protein-binding technique, exceeded metoestrous values (25 ng/ml plasma) from day 3 of pseudopregnancy onwards. The highest levels were found on days 6 and 8 (91 ng/ml). From day 8 onwards the levels decreased gradually but were still above metoestrous values on the day of pro-oestrus after pseudopregnancy. Concentrations of oestradiol-17β, as measured by radioimmunoassay, were within the range of those at metoestrus (about 5 pg/ml plasma) until day 10. Thereafter levels increased to a value of 57 pg/ml. Concentrations of FSH, measured by radioimmunoassay, were within the range of metoestrous values until day 10 (about 100 ng NIAMD-rat-FSH RP-1/ml serum), but declined to a level of 33 ng/ml on day 12. Concentrations of LH, measured by radioimmunoassay, were generally within the wide range of metoestrous values (9–60 ng NIAMD-rat-LH RP-1/ml serum), but concentrations found on days 4, 8 and 10 were significantly lower than those found on preceding or subsequent days. Histological determination of the number of follicles present in various volume-classes, showed an increase in antral follicles on days 1 and 2, comparable to the increase observed during metoestrus and dioestrus 1 of the normal cycle. There was no change in the follicles between days 3 and 10 and they resembled those of early dioestrus. Preovulatory growth had occurred by day 12. Injection of human chorionic gonadotrophin (HCG) on days 2, 4 or 6 showed that ovulation could be induced only in some of the larger follicles. On the basis of these results it is suggested that during pseudopregnancy the high progesterone levels present result in a decreased plasma LH level which is insufficient to cause full maturation of the follicles and to stimulate oestrogen secretion to the levels required for induction of an ovulatory surge of LH release.

THE SECRETION OF IMMUNO-REACTIVE LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE BY THE HUMAN FOETAL PITUITARY IN ORGAN CULTURE

1971 ◽  
Vol 49 (2) ◽  
pp. 335-NP ◽  
Author(s):  
G. V. GROOM ◽  
M. A. GROOM ◽  
I. D. COOKE ◽  
A. R. BOYNS
Keyword(s):  
Growth Hormone ◽  
Tissue Culture ◽  
Luteinizing Hormone ◽  
Organ Culture ◽  
Morphological Change ◽  
Gestational Age ◽  
Follicle Stimulating Hormone ◽  
Unstimulated Control ◽  
Lh Release ◽  
Stimulating Hormone

SUMMARY Foetal human pituitaries of 8–18 weeks gestational age were maintained in tissue culture for up to 6 days. No morphological change was observed in the tissue during this period. Radioactive glucosamine was continuously incorporated into medium protein and the levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and growth hormone in the medium increased with the duration of the culture. Theophylline stimulated the release of both LH and FSH consistently over the 6 days, and the total amount of each hormone released over this period was significantly greater than that in unstimulated control cultures. Cyclic adenosine 3′,5′-monophosphate stimulated FSH release to some extent but had no significant effect on LH release.

ADMINISTRATION OF ANTISERUM AGAINST OVINE FOLLICLE-STIMULATING HORMONE OR OVINE LUTEINIZING HORMONE AT PRO-OESTRUS IN THE RAT: EFFECTS ON FOLLICULAR DEVELOPMENT DURING THE ONCOMING CYCLE

1976 ◽  
Vol 70 (2) ◽  
pp. 301-306 ◽  
Author(s):  
R. WELSCHEN ◽  
J. DULLAART
Keyword(s):  
Luteinizing Hormone ◽  
Histological Study ◽  
Follicle Stimulating Hormone ◽  
Follicular Development ◽  
Antral Follicles ◽  
Lh Release ◽  
Ovulatory Follicles ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Stimulating Hormone

SUMMARY Cyclic rats received at 13.00 h on the day of pro-oestrus a single i.v. injection of one of the following antiserum preparations: AOLH (raised in rabbits against NIH-LH-S17); AOFSH (raised against NIH-FSH-S9) or pAOFSH (AOFSH preincubated with 195 μg NIH-LH-S16/ml). Rats were killed at day 1, 3 or 5 after injection, and the ovaries prepared for histological study of the antral follicles. After AOLH, ovulation and resumption of meiosis in oocytes in pre-ovulatory follicles were prevented but follicular development during the following cycle appeared undisturbed. After either AOFSH or pAOFSH, blockade of ovulation was never observed but the formation of antral follicles normally occurring between mid-pro-oestrus and mid-oestrus was postponed by about one day. The later development of antral follicles might reflect a supranormal compensatory secretion of endogenous gonadotrophin because the development does not occur in AOFSH- or pAOFSH-treated rats hypophysectomized 24 h after injection and subsequently treated with pregnant mare serum gonadotrophin in dosage approximating the amount of gonadotrophin secreted endogenously during dioestrus. The results imply (1) that the pre-ovulatory surge of LH release is not essential for follicular development during the oncoming cycle whereas (2) a surge of FSH release is required for the formation of the new cohort of antral follicles that is normally seen at the start of a new cycle.

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