A study of luteinizing hormone secretion in the cow

Reproduction ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 135-136 ◽  
Author(s):  
L. Cummins ◽  
M. Blockey ◽  
J. Brown ◽  
Goding
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion

Androgenic and oestrogenic steroid participation in feedback control of luteinizing hormone secretion in male sheep

1983 ◽  
Vol 102 (4) ◽  
pp. 499-504 ◽  
Author(s):  
M. J. D'Occhio ◽  
B. D. Schanbacher ◽  
J. E. Kinder
Keyword(s):  
Luteinizing Hormone ◽  
Pulse Generator ◽  
Hormone Secretion ◽  
Pulse Interval ◽  
Serum Concentrations ◽  
Luteinizing Hormone Secretion ◽  
Lh Release ◽  
Lh Secretion ◽  
Additional Feedback ◽  
Male Sheep

Abstract. The acute castrate ram (wether) was used as an experimental model to investigate the site(s) of feedback on luteinizing hormone (LH) by testosterone, dihydrotestosterone and oestradiol. At the time of castration, wethers were implanted subdermally with Silastic capsules containing either crystalline testosterone (three 30 cm capsules), dihydrotestosterone (five 30 cm capsules) or oestradiol (one 6.5 cm capsule). Blood samples were taken at 10 min intervals for 6 h 2 weeks after implantation to determine serum steroid concentrations and to characterize the patterns of LH secretion. Pituitary LH response to exogenous LRH (5 ng/kg body weight) were also determined at the same time. The steroid implants produced serum concentrations of the respective hormones which were either one-third (testosterone) or two-to-four times (dihydrotestosterone, oestradiol) the levels measured in rams at the time of castration. Non-implanted wethers showed rhythmic pulses of LH (pulse interval 40–60 min) and had elevated LH levels (16.1 ± 1.6 ng/ml; mean ± se) 2 weeks after castration. All three steroids suppressed pulsatile LH release and reduced mean LH levels (to below 3 ng/ml) and pituitary LH responses to LRH. Inhibition of pulsatile LH secretion by all three steroids indicated that testosterone as well as its androgenic and oestrogenic metabolites can inhibit the LRH pulse generator in the hypothalamus. Additional feedback on the pituitary was indicated by the dampened LH responses to exogenous LRH.

Opioid Control of Luteinizing Hormone Secretion in Patients with Hirsutism and Hyperandrogenemia

1987 ◽  
Vol 23 (2) ◽  
pp. 117-121 ◽  
Author(s):  
Felice Petraglia ◽  
Susanna Golinelli ◽  
Gerardo d’Ambrogio ◽  
Giuseppina Comitini ◽  
Fabio Facchinetti ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion

Effects of valproate-induced alteration of the GABAergic system on pulsatile luteinizing hormone secretion in ovariectomized women

1996 ◽  
Vol 135 (3) ◽  
pp. 293-298 ◽  
Author(s):  
Joaquin Lado-Abeal ◽  
Jose L Liz ◽  
Carlos Rey ◽  
Manuel Febrero ◽  
Jose Cabezas-Cerrato
Keyword(s):  
Luteinizing Hormone ◽  
Sodium Valproate ◽  
Pulse Generator ◽  
Hormone Secretion ◽  
Gabaergic System ◽  
Luteinizing Hormone Secretion ◽  
Serum Lh ◽  
Nutrition Service ◽  
Significant Difference ◽  
Lh Secretion

Lado-Abeal J, Liz JL, Rey C, Febrero M, Cabezas-Cerrato J. Effects of valproate-induced alteration of the GABAergic system on pulsatile luteinizing hormone secretion in ovariectomized women. Eur J Endocrinol 1996;135:293–8. ISSN 0804–4643 It is well established that valproate increases hypothalamic concentrations of γ-aminobutyric acid (GABA). Although little research has been done on the role of GABA in the control of pulsatile luteinizing hormone (LH) secretion in humans, our group recently found that administration of valproate had no significant effect on pulsatile LH secretion in late follicular and mid-late luteal phase normal women. However, the results of several studies of rats suggest that GABAergic regulation of LH secretion may depend on steroid levels. The objective of this work was to determine whether regular administration of sodium valproate inhibits pulsatile LH secretion in ovariectomized women. Twelve women who had undergone ovariectomy for causes other than malignant tumors were each studied in two 8 h sessions, in each of which blood samples were taken every 5 min. The first session was the control; for the second, 400 mg of sodium valproate was administered every 8 h during the seven preceding days and at 08.00 h and 14.00 h on the day of the study session. Serum valproate was determined by repolarization fluorescence spectrophotometry, and LH, estradiol and progesterone by radioimmunoassay. The serum LH series were subjected to a deconvolution procedure to reconstruct the pattern of pituitary LH secretion. Luteinizing hormone pulses were identified by the authors' nonparametric method. Control and post-valproate results were compared with regard to number of pulses, pulse duration, the quantity of LH secreted in each pulse, interpulse interval and mean serum LH level. There was no statistically significant difference between control and post-valproate results for any of the variables considered. It is concluded that sustained serum valproate levels do not alter pulsatile secretion of LH in ovariectomized women. This implies that, in humans, GABA is probably not a decisive factor in the regulation of the GnRH pulse generator. J Cabezas-Cerrato, Endocrinology and Nutrition Service, General Hospital of Galicia, c/Galeras s/n 15705, Santiago de Compostela, La Coruña, Spain

Pulsatile luteinizing hormone secretion pattern in hyperandrogenemic women

1994 ◽  
Vol 44 (1) ◽  
pp. 94-95
Author(s):  
M.A. Graf ◽  
P. Bielfeld ◽  
W. Distler ◽  
C. Weiers ◽  
W.N. Kuhn-Velten
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion

EFFECT OF HYPOTHALAMIC DEAFFERENTATION ON THE CONTROL OF LUTEINIZING HORMONE SECRETION

1970 ◽  
Vol 46 (1) ◽  
pp. 1-7 ◽  
Author(s):  
S. TALEISNIK ◽  
M. E. VELASCO ◽  
J. J. ASTRADA
Keyword(s):  
Luteinizing Hormone ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Hormone Secretion ◽  
Feedback Effect ◽  
Luteinizing Hormone Secretion ◽  
Ovarian Steroids ◽  
Medial Hypothalamus ◽  
Lh Release ◽  
Positive Feedback Effect

SUMMARY The influence that the interruption of the neural afferents to the hypothalamus exerts on ovulation and on the release of luteinizing hormone (LH) was studied in the rat. Animals with retrochiasmatic sections interrupting the neural connexions between the medial hypothalamus and the preoptic area (POA) showed constant oestrus and failed to ovulate. Animals in which the dorsal neural afferents to the POA were transected had oestrous cycles and ovulated normally. The positive feedback effect of progesterone on LH release in spayed animals primed either with 20 μg. oestradiol benzoate or 2·5 mg. testosterone propionate 3 days before was studied. Transection of the dorsal afferents to the POA favoured an increase in plasma LH, but in animals with retrochiasmatic sections the response was abolished. However, the negative feedback effect of ovarian steroids operated after both types of transection because an increase in plasma LH occurred after ovariectomy. It is concluded that the negative feedback effect of ovarian steroids acts on the medial hypothalamus which can maintain a tonic release of gonadotrophins in the absence of steroids. In contrast, the POA involved in the positive feedback effect of progesterone is concerned with the phasic release of LH.

Pulsatile immunoreactive and bioactive luteinizing hormone secretion in adolescents with chronic renal failure

1991 ◽  
Vol 5 (4) ◽  
pp. 566-571 ◽  
Author(s):  
F. Schaefer ◽  
C. Seidel ◽  
R. Mitchell ◽  
K. Sch�rer ◽  
W. R. Robertson ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion

Effects of alarin on food intake, body weight and luteinizing hormone secretion in male mice

Neuropeptides ◽  
2012 ◽  
Vol 46 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Gregory S. Fraley ◽  
Emily Leathley ◽  
Nicole Lundy ◽  
Emily Chheng ◽  
Issurah King ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Male Mice ◽  
Luteinizing Hormone Secretion
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