Secretion patterns of luteinising hormone, follicle-stimulating hormone and 17β-oestradiol during oestrus and the mid-luteal phase of the oestrous cycle in mithun (Bos frontalis)

2006 ◽  
Vol 18 (6) ◽  
pp. 619 ◽  
Author(s):  
A. Dhali ◽  
D. P. Mishra ◽  
M. Karunakaran ◽  
A. Mech ◽  
C. Rajkhowa
Keyword(s):  
Luteal Phase ◽  
Luteinising Hormone ◽  
Regulatory Mechanism ◽  
Follicle Stimulating Hormone ◽  
Peripheral Circulation ◽  
Oestrous Cycle ◽  
Pulsatile Secretion ◽  
Basal Plasma ◽  
Lh Release ◽  
Stimulating Hormone

The present study reports the pulsatile secretion of gonadotrophins and 17β-oestradiol (OE2) on the day of oestrus and at the mid-luteal phase of the oestrous cycle in mithun (Bos frontalis). The frequency of luteinising hormone (LH) and follicle-stimulating hormone (FSH) pulses was found to be greater (P < 0.05) on the day of oestrus than at the mid-luteal phase. In contrast, the amplitude of the LH and FSH pulses was greater (P < 0.01) at the mid-luteal phase than on the day of oestrus. A synchronised (P < 0.01) LH and FSH secretion pattern was found only at the mid-luteal phase. A pulsatile secretion pattern for OE2 in the peripheral circulation was evident for both phases of the oestrous cycle. The frequency of the OE2 pulses did not differ significantly in different phases of the oestrous cycle. In contrast, the amplitude of the OE2 pulses and the basal OE2 concentration were found to be greater (P < 0.01) at the mid-luteal phase than on the day of oestrus. A synchronised (P < 0.01) LH and OE2 secretion pattern was observed in both phases of the oestrous cycle. In contrast, a synchronised (P < 0.05) FSH and OE2 secretion pattern was found only on the day of oestrus. In conclusion, a different pattern of LH and FSH secretion was observed in both phases of the oestrous cycle, mainly on the day of oestrus, which indicates a differential regulatory mechanism of LH and FSH release. In addition, as in cattle, OE2 exerts a positive feedback on LH and FSH release on the day of oestrus and on LH release at the mid-luteal phase of the oestrous cycle in mithun. Also, as in cattle, the greater basal plasma OE2 concentration and increased amplitude of OE2 pulses exert a negative feedback on FSH release at the mid-luteal phase of the oestrous cycle.

scholarly journals Concurrent Pulsatile Secretion of Luteinizing Hormone and Follicle-Stimulating Hormone during Different Phases of the Estrous Cycle and Anestrus in Beagle Bitches

1999 ◽  
Vol 60 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Hans S. Kooistra ◽  
Auke C. Okkens ◽  
Mart M. Bevers ◽  
Corrie Popp-Snijders ◽  
Bas van Haaften ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Estrous Cycle ◽  
Follicle Stimulating Hormone ◽  
Pulsatile Secretion ◽  
Stimulating Hormone

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.

Relationships between follicle-stimulating hormone, follicle growth and ovulation rate in sheep

1996 ◽  
Vol 8 (2) ◽  
pp. 279 ◽  
Author(s):  
RC Fry ◽  
MA Driancourt
Keyword(s):  
Follicle Stimulating Hormone ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Follicle Growth ◽  
Group I ◽  
Group 3 ◽  
Group 2 ◽  
Group 1 ◽  
Stimulating Hormone

The changes in follicle-stimulating hormone (FSH) concentration required to affect follicle growth and ovulation rate within individual ewes were examined. Relationships between peripheral FSH concentrations during the late-luteal and follicular phase and subsequent ovulation rates were investigated in 22 ewes from 4 breeds over 3 successive cycles (Experiment 1). Ewes were grouped as follows: Group 1 (n = 6), ewes exhibiting the same ovulation rate at each oestrous cycle: Group 2 (n = 5), ewes with three different ovulation rates at each oestrous cycle; and Group 3 (n = 11), ewes with the same ovulation rate at two oestrous cycles and a different ovulation rate on one occasion. Data from ewes in Group 1 and 3 provided estimates on the variation in FSH concentrations between cycles which were not large enough to alter ovulation rate (range, 0-67% variation in FSH concentration). In Group-2 ewes, there was no consistent association between increases in ovulation rate and the proportional increases in FSH concentrations. Differences in FSH concentrations were often less than those that did not alter ovulation rate in Group-I ewes. Furthermore, only 3 of 11 Group-3 ewes demonstrated high FSH concentrations associated with high ovulation rate (or low FSH concentrations and low ovulation rate) when compared with the concentrations found at the two cycles in which ovulation rate was similar. Hence, there was little evidence that FSH concentrations during the late-luteal and follicular phase are associated with changes in ovulation rate within individual ewes. In Experiment 2, follicles of similar size obtained from the same ewe (FecBFec+ and Romanov) showed markedly different responses in vitro to graded doses of FSH as measured by aromatase activity. It is concluded that, within a ewe, the large variability between gonadotrophin-dependent follicles in their requirement for FSH prevented the expression of any thresholds of ovarian response to FSH.

THE EFFECT OF CYPROTERONE ACETATE ON THE PLASMA GONADOTROPHIN RESPONSE TO GONADOTROPHIN RELEASING HORMONE

1976 ◽  
Vol 81 (3) ◽  
pp. 680-684 ◽  
Author(s):  
Richard A. Donald ◽  
Eric A. Espiner ◽  
R. John Cowles ◽  
Joy E. Fazackerley
Keyword(s):  
Testosterone Level ◽  
Cyproterone Acetate ◽  
Luteinising Hormone ◽  
Follicle Stimulating Hormone ◽  
Plasma Testosterone ◽  
Plasma Testosterone Level ◽  
Releasing Hormone ◽  
Lh Release ◽  
Gonadotrophin Releasing Hormone ◽  
Male Patients

ABSTRACT Cyproterone acetate (100–150 mg daily) was administered to 8 male patients with excessive libido. Within 3 months a significant fall (P < 0.02) in plasma testosterone was demonstrated. The plasma luteinising hormone (LH) and follicle stimulating hormone (FSH) responses to gonadotrophin releasing hormone (LH/FSH-RH) were also significantly impaired (P < 0.05). A direct correlation between the resting plasma testosterone level and the LH response to LH/FSH-RH was demonstrated (r = 0.743). It is concluded that the fall in plasma testosterone levels in patients receiving cyproterone acetate may be attributed to suppression of LH release, rather than an antiandrogen effect on the testis or hypothalamus.

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