Role of Hypothalamic Catecholamines in the Regulation of Luteinizing Hormone and Prolactin Secretion in the Ewe during Seasonal Anestrus

1989 ◽  
Vol 49 (1) ◽  
pp. 80-87 ◽  
Author(s):  
Jean-Claude Thiéry ◽  
Graeme B. Martin ◽  
Yves Tillet ◽  
Martine Caldani ◽  
Monique Quentin ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Prolactin Secretion

EFFECT OF ERGOT ALKALOIDS UPON LUTEAL FUNCTION IN THE FERRET

1974 ◽  
Vol 60 (1) ◽  
pp. 91-99 ◽  
Author(s):  
F. R. BLATCHLEY ◽  
B. T. DONOVAN
Keyword(s):  
Luteinizing Hormone ◽  
Histological Examination ◽  
Ergot Alkaloids ◽  
Prolactin Secretion ◽  
Luteal Function

SUMMARY Since ergocornine is believed to block prolactin secretion in several species, the drug was given to pseudopregnant ferrets in an attempt to define the rôle of the hormone in the control of luteal function. The effects of ergocornine, and of the more potent analogue 2-bromo-α-ergocryptine, were followed by assay of the progestin content of the blood and histological examination of the ovaries. Ergocornine was given at the time of induction of pseudo-pregnancy by an injection of luteinizing hormone (day 0), on day 1, days 0 and 1, days 0, 2, 4 and 6, or day 7, and 2-bromo-α-ergocryptine on days 0, 1, 2 and 3, or 7, 8, 9 and 10. A lasting depression of plasma progestin content occurred after the injection of ergocornine on days 0 and 1, perhaps because of interference with the formation of the luteal bodies. Other injection régimes had little effect on progestin secretion.

Role of Luteinizing Hormone in Control of Oviduct Function

2000 ◽  
Vol 35 (3-4) ◽  
pp. 129-133
Author(s):  
B Gawronska ◽  
A Stepien ◽  
AJ Ziecik
Keyword(s):  
Luteinizing Hormone

ZUR BEDEUTUNG DES HYPOPHYSÄREN LUTEINISIERUNGSHORMONS FÜR SCHWANGERSCHAFT, GEBURT UND LACTATION BEI DER RATTE

1970 ◽  
Vol 65 (3_Suppl) ◽  
pp. S5-S32 ◽  
Author(s):  
K. Loewit
Keyword(s):  
Luteinizing Hormone ◽  
Early Pregnancy ◽  
Hydroxysteroid Dehydrogenase ◽  
The State ◽  
Termination Of Pregnancy ◽  
Progesterone Level ◽  
Corpora Lutea ◽  
Regulatory Properties ◽  
Duration Of Pregnancy

ABSTRACT The role of luteinizing hormone (LH) for the maintenance of pregnancy, parturition and lactation was investigated by immunological and histochemical methods in the rat. Neutralisation of endogenous rat-LH with Rabbit-Anti-Bovine-LH-Serum (selective hypophysectomy) from days 7-12 of pregnancy resulted in reabsorption of the foetuses and the reappearance of strong 20α-hydroxysteroid-dehydrogenase (20α-OHSD) activity in the corpora lutea (CL) of pregnancy, which normally show no such activity at that time. This effect could be prevented in part by concurrent pregnenolone administration and fully by progesterone, but was not influenced by oestrogen or prolactin. It is concluded that in early pregnancy LH is the main luteotrophic hormone in the rat even though prolactin might act synergistically with it. Antiserum treatment after the 12th day of gestation had no influence on the state or duration of pregnancy or on parturition. LH-injections during the first half of pregnancy had no luteolytic effects i. e. they did not activate 20α-OHSD activity. After day 16 they advanced the reappearance of the enzyme, but delayed parturition or resulted in stillbirths. Neither LH nor antiserum seemed to alter lactation. Since progesterone prevented both the termination of pregnancy and the recurrence of 20α-OHSD activity, it should have some regulatory properties on the enzyme. It is discussed whether the gonadotrophin-dependent progesterone level could regulate the 20α-OHSD activity rather than result from it.

FEEDBACK CONTROL OF FSH IN THE MALE: ROLE OF OESTROGEN

1973 ◽  
Vol 74 (3) ◽  
pp. 449-460 ◽  
Author(s):  
Patrick C. Walsh ◽  
Ronald S. Swerdloff ◽  
William D. Odell
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Oestrogen Therapy ◽  
Serum Concentrations ◽  
Elderly Men ◽  
Normal Range ◽  
Oestrogen Treatment ◽  
Serum Lh ◽  
Higher Doses

ABSTRACT Serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) were measured by radioimmunoassay in a group of elderly men following castration and oestrogen therapy. Prior to orchiectomy, mean serum concentrations of LH and FSH were within the normal range. Two days following castration, serum LH concentrations increased in all eight patients; higher levels of LH were subsequently measured in all but one patient after periods of time ranging from 49 to 210 days. Serum FSH levels, measured in three patients following castration, increased in a pattern parallel to LH changes. Ethinyl oestradiol (EOe) in doses ranging from 5 to 300 μg/day was administered to ten men who had been castrated 3 to 72 months earlier. Oestrogen treatment suppressed both LH and FSH in a parellel manner in nine of ten patients. LH was first suppressed to intact levels in one of eight patients treated with 20 μg/day of EOe, in two of six patients treated with 50 μg/day, and in one patient by 80 μg/day. FSH was not suppressed to precastration levels until 50 μg/day of EOe was administered; this dose suppressed three of six patients. Higher doses of EOe (150–300 μg/day) suppressed both LH and FSH to levels below the sensitivity of the assay. These data fail to demonstrate any differential effect of oestrogen on LH and FSH release.

Role of Ca2+ and Na+ on luteinizing hormone release from the calf pituitary

1988 ◽  
Vol 255 (4) ◽  
pp. E469-E474
Author(s):  
J. P. Kile ◽  
M. S. Amoss
Keyword(s):  
Luteinizing Hormone ◽  
Ionophore A23187 ◽  
Channel Blockers ◽  
Hormone Release ◽  
Primary Cells ◽  
Rat Pituitary ◽  
Voltage Dependent ◽  
Lh Release ◽  
Ca2 Channels

It has been proposed that gonadotropin-releasing hormone (GnRH) stimulates Ca2+ entry by activation of voltage-independent, receptor-mediated Ca2+ channels in the rat gonadotroph. Little work has been done on the role of calcium in GnRH-induced luteinizing hormone (LH) release in species other than the rat. Therefore, this study was done to compare the effects of agents that alter Ca2+ or Na+ entry on LH release from calf anterior pituitary primary cells in culture. GnRH (100 ng/ml), Ca2+ ionophore A23187 (2.5 microM), and the depolarizing agent ouabain (0.1-10 microM) all produced significant increases (P less than 0.05) in LH release; these effects were significantly reduced when the cells were preincubated with the organic Ca2+ channel blockers nifedipine (1-10 microM) and verapamil (1-10 microM) and with Co2+ (0.01-1 mM). The effect of ouabain was inhibited by tetrodotoxin (TTX; 1-10 nM) as well as by nifedipine at 0.1-10 microM. In contrast to its effect on rat pituitary LH release, TTX significantly inhibited GnRH-stimulated LH release at 1-100 nM. These results suggest that GnRH-induced LH release may employ Ca2+ as a second messenger in bovine gonadotrophs and support recent speculation that GnRH-induced Ca2+ mobilization may in part be voltage dependent.

Spontaneous follicular and luteal function in infertile women with oligomenorrhoea: role of luteinizing hormone

1995 ◽  
Vol 43 (6) ◽  
pp. 735-739 ◽  
Author(s):  
R. Fleming ◽  
D. McQueen ◽  
R. W. S. Yates ◽  
J. R. T. coutts
Keyword(s):  
Luteinizing Hormone ◽  
Luteal Function ◽  
Infertile Women

Pineal denervation by cervical sympathetic ganglionectomy suppresses the role of photoperiod on pregnancy or pseudopregnancy, body weight and moulting periods in the mink (Mustela vison)

1985 ◽  
Vol 107 (1) ◽  
pp. 31-39 ◽  
Author(s):  
L. Martinet ◽  
D. Allain ◽  
Y. Chabi
Keyword(s):  
Body Weight ◽  
Environmental Factors ◽  
Prolactin Secretion ◽  
Corpora Lutea ◽  
Progesterone Secretion ◽  
Cervical Ganglion ◽  
Cervical Sympathetic ◽  
Implantation Period ◽  
Short Days

ABSTRACT In mink, termination of the delayed implantation period, following reactivation of the corpora lutea, and onset of the spring moult are associated with a rise in prolactin secretion triggered by increasing daylength, while decreasing daylength induces the autumn moult. To establish whether suppression of the function of the pineal rendered the mink unresponsive to daylength changes, the superior cervical ganglion was removed bilaterally 2–4 weeks before mating. Intact and operated females were then left outdoors or were put under a lighting regime of either 15 h light: 9 h darkness (15L: 9D) or 8L: 16D. In July, at the end of the spring moult, the 15L: 9D lighting regime was changed to one of 8L: 16D. Under artificial photoperiods ganglionectomy suppressed the stimulatory role of long days and the inhibitory role of short days on prolactin secretion, and consequently on progesterone secretion and spring moult. Neither was the autumn moult, induced early in intact females by the change to a short photoperiod, advanced in ganglionectomized females, showing that the latter were unresponsive to the artificial modification of the photoperiod. However, in animals kept outdoors, prolactin and progesterone secretion and spring moult were not changed by ganglionectomy. Increase in body weight and autumn moult were only slightly delayed by the operation suggesting that other environmental factors had replaced the synchronizing effect of the daylength changes. Alternatively the desynchronization between intact females responsive to photoperiodism and those rendered unresponsive may be too slow to be observed soon after ganglionectomy. J. Endocr. (1985) 107, 31–39

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