Plasma LH levels following electrochemical stimulation of the deafferented medial basal hypothalamus

1980 ◽  
Vol 94 (1) ◽  
pp. 11-17
Author(s):  
A. J. Carrillo ◽  
N. Hagino ◽  
G. Setalo
Keyword(s):  
Median Eminence ◽  
Jugular Vein ◽  
External Jugular Vein ◽  
Female Rats ◽  
Medial Basal Hypothalamus ◽  
Blood Samples ◽  
Ether Anaesthesia ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Stimulation Of

Abstract. We have investigated the capability of a completely deafferented medial basal hypothalamus (MBH) pituitary complex to support LH release following electrochemical stimulation (ECS) of the arcuate-median eminence (ARC-ME) region. In adult female rats the MBH was completely deafferented (CD) on the morning of pro-oestrus (08.00-10.00 h of day 0). In the first experiment the animals were divided into 5 groups depending on the day of ECS (14.00–16.00 h) and oestradiol benzoate (Oe) treatment (08.00–10.00 h): group No. 1) ECS on day 0; 2) no ECS; 3) ECS on day 1; 4) Oe on day 0 and ECS on day 1; 5) Oe on day 4 and ECS on day 5. Blood samples were collected from the external jugular vein under ether anaesthesia for LH determinations just before and 1 and 2 h after ECS. ECS on day 0 resulted in a significant (P<0.01) rise in plasma LH at 1 and 2 h, while the rats subjected to CD, but not ECS failed to show any changes in plasma LH levels. ECS on days I and 5 (groups 3 and 5) failed to alter plasma LH levels, however, ECS on day 1 in Oe treated rats produced a significant (P < 0.01) elevation in plasma LH that was comparable to that of day 0. In a second experiment Oe was injected on days 1–5 and ECS of the ARC-ME was done bilaterally. ECS on day 5 resulted in a significant (P < 0.05) rise in plasma LH levels in rats with a completely deafferented MBH. In animals with an incomplete deafferentation ECS resulted in a much greater (P < 0.005) rise in plasma LH at l and 2 h. Since LH was released several days after complete hypothalamic deafferentation, these data suggest that LRH secreting cells may be present within the MBH of the rat. In a third experiment injection of LRH (400 ng) on days 0, 1 and 5 with Oe on days 0, 4 or 1–5 resulted in a significant (P < 0.001) rise of plasma LH at 30 and 60 min in all groups. Rats injected on day 0 showed the greatest elevation at 60 min in all groups. Saline injected rats did not show any changes in plasma LH levels.

Circulating blood progesterone is pulsatile throughout the rat oestrous cycle

1987 ◽  
Vol 116 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Ok-Kyong Park ◽  
Victor D. Ramirez
Keyword(s):  
Jugular Vein ◽  
Recovery Period ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Individual Data ◽  
Blood Samples ◽  
Ether Anaesthesia ◽  
Heparinized Saline ◽  
Freely Moving ◽  
First Time

Abstract. In the present experiment, we determined circulating progesterone (P4) levels of intact cycling female rats. A cannula constructed from polyethylene50 tubing containing heparinized saline was inserted into the jugular vein of the rat under light ether anaesthesia and after a 3–6 h recovery period sequential blood samples were withdrawn from unanaesthetized, freely-moving rats. Blood samples (80–100 μl) were collected at 10-min intervals for 6 h and the volume was replaced with saline. Plasma P4 was determined using a specific P4 radioimmunoassay. Four rats in each of three phases of the rat oestrous cycle (E, Dl, D2) were examined. In addition, rats in proestrus were divided into an early (EP, N = 4) and a late (LP, N = 4) proestrous conditions. Individual data were analyzed by PULSAR as adapted for an IBM-PC. P4 was found to fluctuate in a pulsatile mode throughout the rat oestrous cycle. Mean levels of circulating P4 were lowest (38.8 ± 1.7 nmol/l plasma) in EP and highest (122.5 ± 1.3) in Dl. The frequency of P4 pulses was dramatically decreased in Dl (2.50 ± 0.86 pulses/6 h), whereas no difference was found among the other days of the cycle (7.25 ± 0.47 in E, 7.25 ± 0.85 in D2, 5.75 ± 1.31 in EP, and 6.50 ± 1.04 in LP). Interestingly, the amplitude of P4 pulses was significantly lower in EP (14.0 ± 2.91 pmol), whereas no difference was found among other groups. Another group of experimental animals were ovariectomized (N = 4; two with and two without an implant of a silastic capsule of P4) and similarly bled. These animals demonstrated a fairly stable circulating pattern of P4. The present data demonstrate for the first time that P4 in rat blood fluctuates in a pulsatile manner.

EFFECTS OF PINEALECTOMY ON THE RAT OESTROUS CYCLE AND PITUITARY GONADOTROPHIN RELEASE

1976 ◽  
Vol 69 (1) ◽  
pp. 67-75 ◽  
Author(s):  
C. A. BLAKE
Keyword(s):  
Pineal Gland ◽  
Oestrous Cycle ◽  
Ovariectomized Rats ◽  
Prolactin Release ◽  
Medial Basal Hypothalamus ◽  
Blood Samples ◽  
Serum Lh ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Permissive Role

SUMMARY In 4-day cyclic rats kept in a room with the lights on from 05.00 to 19.00 h, sham pinealectomy or pinealectomy on the morning of pro-oestrus did not alter the length of the oestrous cycle for 44 days or the time and magnitude of the rises in LH, FSH and prolactin in the circulation in the afternoon on pro-oestrous days 0, 20 or 44. On day 45, the light schedule was set forward 4 h to run from 09.00 to 23.00 h. The rats continued to have seven additional consecutive 4-day oestrous cycles. On day 27 after the resetting of the light schedule, the pro-oestrous rises in serum LH, FSH and prolactin were delayed 4 h in all rats and a normal quota of eggs was ovulated that night. Other 4- and 5-day cyclic rats which had been made persistently oestrous by anterior deafferentation of the medial basal hypothalamus (AC) underwent pinealectomy. These AC-pinealectomized rats were ovariectomized 60 days later and histological examination of the ovaries revealed no evidence of recent ovulation. Five to six weeks after ovariectomy, sequential blood samples were withdrawn through indwelling atrial cannulas in the AC-pinealectomized-ovariectomized rats and in ovariectomized, pinealectomized-ovariectomized and AC-ovariectomized rats. Regular pulsatile rhythms in plasma LH were measured in all rats. Subcutaneous injection of 50 μg oestradiol benzoate in oil lowered plasma LH levels in all four groups but caused an LH surge in the afternoon 2 days later only in the ovariectomized and pinealectomized-ovariectomized rats. The results indicate that the pineal gland in rats kept on a 14 h light: 10 h darkness schedule does not play an active or permissive role in the timing or magnitude of LH, FSH or prolactin release at pro-oestrus, the length of the oestrous cycle, or LH release in ovariectomized rats.

ADENOHYPOPHYSEAL LH CONTENT IN NORMAL, ANDROGEN-STERILIZED AND PROGESTERONE-PRIMED STERILE FEMALE RATS

1962 ◽  
Vol 39 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Roger A. Gorski ◽  
Charles A. Barraclough
Keyword(s):  
Ascorbic Acid ◽  
Electrical Stimulation ◽  
Quantitative Determination ◽  
Median Eminence ◽  
Hypothalamic Stimulation ◽  
Female Rats ◽  
Rat Pituitary ◽  
Gland Content ◽  
Stimulation Of

ABSTRACT We have previously suggested that the failure of the androgen-sterilized, persistent-oestrous rat to ovulate, following electrical stimulation of the median eminence structures of the hypothalamus, is due to an insufficiency in adenohypophyseal LH concentration. Using the ovarian ascorbic acid technique for quantitative determination of pituitary LH content, the present studies have demonstrated that the sterile rat pituitary gland contains one-third the LH content of the normal prooestrous gland. Furthermore, not only does progesterone priming of this persistent-oestrous rat result in a 75 % increase in LH concentration, but on hypothalamic stimulation sufficient LH is released to induce ovulation. The decrease in LH concentration which accompanies ovulation in the progesterone-primed, sterile rat is approximately 45 % of the total gland content as compared with a 51 % decrease in pituitary content in the normal cyclic rat.

Cortical Spreading Depression Does Not Result in the Release of Calcitonin Gene-Related Peptide into the External Jugular Vein of the Cat: Relevance to Human Migraine

Cephalalgia ◽  
1993 ◽  
Vol 13 (3) ◽  
pp. 180-183 ◽  
Author(s):  
Richard D Piper ◽  
Lars Edvinsson ◽  
Rolf Ekman ◽  
Geoffrey A Lambert
Keyword(s):  
Migraine With Aura ◽  
Cortical Spreading Depression ◽  
Spreading Depression ◽  
Jugular Vein ◽  
Calcitonin Gene Related Peptide ◽  
External Jugular Vein ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
Vasoactive Peptide ◽  
Stimulation Of

There is circumstantial evidence that cortical spreading depression (SD) may account for the scotoma and the “spreading cortical oligemia” seen during migraine with aura. It has been shown that calcitonin gene-related peptide (CGRP) is increased in blood taken from the external jugular vein (EJV) in humans during migraine and after stimulation of the trigeminal ganglion. To test the hypothesis that cortical SD may elevate the concentration of this vasoactive peptide in the EJV during migraine, we have measured its concentration in the external jugular vein of cats during cortical SD. This study demonstrates that SD has no effect on the concentration of CGRP either during the passage of a wave of spreading depression across the cortex or, 60 min later, during the period of post-SD cortical oligemia.

SENSITIVITY OF ANTERIOR HYPOTHALAMIC AREAS TO GONADAL STEROID IMPLANTATION IN ANDROGENIZED FEMALE RATS

1977 ◽  
Vol 74 (2) ◽  
pp. 315-NP ◽  
Author(s):  
A. DANGUY ◽  
J. L. PASTEELS ◽  
F. ECTORS
Keyword(s):  
Single Injection ◽  
Mammary Glands ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Male Rats ◽  
Control Synthesis ◽  
Normal Female ◽  
Immunofluorescence Studies ◽  
Oestradiol Benzoate ◽  
Stimulation Of

A single injection of 1 mg of a complex of testosterone esters on day 5 of life was used to prepare constantly oestrous rats. Such androgenized female rats were then ovariectomized and submitted to stereotaxical implantation of 1 μg oestradiol benzoate, 5 μg testosterone isobutyrate or, as a control, 10 μg cholesterol in the anterior hypothalamic areas. The effects of the steroids on plasma and pituitary FSH and LH were assessed by radioimmunoassay. As reported previously by us in normal female and male rats, the preoptic–suprachiasmatic area (POA) was able to control synthesis and secretion of both gonadotrophins and did not lose its sensitivity to oestradiol and testosterone in androgenized rats. Evidence for enhanced prolactin secretion in androgenized rats was derived from immunofluorescence studies of the pituitary gland and from histology of the mammary glands. In this respect the condition of the androgenized females was opposite to that of the males. The present work demonstrated that stimulation of prolactin secretion in androgenized female rats resulted from oestrogen action due to permanent oestrus rather than from impairment of hypothalamo-hypophysial relationships. Indeed, prolactin stimulation was suppressed when the androgenized rats were ovariectomized and restored when they were subsequently implanted with oestradiol in the POA.

INDUCTION OF PROLACTIN AND LUTEINIZING HORMONE RELEASE BY HISTAMINE IN MALE AND FEMALE RATS AND THE INFLUENCE OF BRAIN TRANSMITTER ANTAGONISTS

1978 ◽  
Vol 76 (2) ◽  
pp. 193-202 ◽  
Author(s):  
A. O. DONOSO
Keyword(s):  
Prolactin Secretion ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Male Rats ◽  
Intraventricular Injection ◽  
Hormone Release ◽  
Stimulatory Action ◽  
Male And Female Rats ◽  
Oestradiol Benzoate ◽  
Lh Release

The levels of prolactin and LH in the plasma of rats were determined at various times after intraventricular injection of histamine. Doses of 5 and 60 μg histamine (free base) in male rats, anaesthetized with ether, induced an increase in the level of prolactin in the plasma, whilst producing a slight decrease in the concentration of LH. Injection of 5 μg histamine at 14.00 h into female rats at all stages of the oestrous cycle caused prolactin to be released; the effect was greatest at oestrus and at day 1 of dioestrus. Histamine also gave rise to a marked increase in the level of LH in the plasma when administered to pro-oestrous rats, but had no effect when injected at the other stages of the oestrous cycle. The effect of histamine on the release of prolactin in ovariectomized, oestradiol benzoate: progesterone-primed (OVX,OB:P) rats was found to be dose-related, and the level of LH in the plasma was increased by as little as 1·25 μg. Pretreatment with adrenergic (phenoxybenzamine and propranolol) and cholinergic (atropine) antagonists failed to block the stimulatory effects of histamine on prolactin secretion, but pretreatment with methysergide (serotonin antagonist) increased the histamine-induced release of prolactin in male rats. Antagonists did not modify the response of prolactin to histamine in OVX,OB:P-primed rats. The histamine-induced release of LH in OVX,OB:P-primed rats was slightly reduced by pretreatment with phenoxybenzamine, propranolol and atropine, but not by methysergide. These results indicate that histamine facilitates the release of prolactin. The stimulatory action of histamine on both pro-oestrous and OVX,OB:P-primed but not male rats suggests that histamine may be involved in LH release in the rat. Results obtained in animals pretreated with transmitter antagonists, which were unable to prevent histamine-induced hormone release, suggest that the actions of this amine are not mediated by cholinergic, noradrenergic or serotonergic mechanisms.

Dissociation between the ovarian factors controlling sexual receptivity and preovulatory secretion of LH in cyclic female rats

1987 ◽  
Vol 112 (1) ◽  
pp. 133-138 ◽  
Author(s):  
P. Södersten ◽  
P. Eneroth
Keyword(s):  
Sexual Behaviour ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
Serum Progesterone ◽  
Lh Surge ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Lh Secretion ◽  
Intact Rats

ABSTRACT Ovariectomy and treatment with oestradiol benzoate (10 μg OB) on the day before behavioural oestrus eliminated the preovulatory surge of LH and reduced the level of sexual receptivity on the following day. Sexual behaviour, but not the LH surge, was restored by progesterone (0·5 mg) given 18 h later. Injection of OB on the day after behavioural oestrus induced a small release of LH and normal sexual behaviour on the following day. Ovariectomy on the day after behavioural oestrus reduced the stimulatory effect of OB on sexual behaviour and eliminated its weakly stimulatory effect on LH release. Sexual behaviour, but not the small LH surge, was restored in these animals by progesterone (0·5 mg) given 18 h later. Treatment of rats ovariectomized 2 days before the day of the LH surge with implants containing oestradiol or injections of oestradiol (1 μg) induced LH surges but the amplitudes of these LH surges were much smaller than those of the normal LH surge. Treatment of intact rats with OB increased serum progesterone levels 24 h later, an effect which was eliminated by ovariectomy. Injections of LH (20 μg) into intact rats on the day after behavioural oestrus also increased serum progesterone concentrations but failed to stimulate sexual behaviour. It is suggested that OB treatment of intact rats on the day after behavioural oestrus stimulates sexual behaviour by inducing a surge of LH secretion which activates ovarian secretion of progesterone. Thus, oestrogen and progesterone but not the LH surge are essential for sexual behaviour. Whereas oestradiol and progesterone restore normal sexual behaviour in ovariectomized rats, additional ovarian factors may be required for induction of normal LH surges. J. Endocr. (1987) 112, 133–138

Electrochemical Stimulation of the Median Eminence Evokes FSH but not LH Release After LHRH Antagonist Treatment

1998 ◽  
Vol 10 (3) ◽  
pp. 231-236 ◽  
Author(s):  
Miklós Koppán ◽  
Magdolna Kovács ◽  
Imre Mezö ◽  
Béla Flerkó
Keyword(s):  
Median Eminence ◽  
Lhrh Antagonist ◽  
Lh Release ◽  
Stimulation Of

scholarly journals STUDIES OF DEPRAVED APPETITE IN EGYPTIAN CATTLE

2018 ◽  
Vol 6 (10) ◽  
pp. 202-211
Author(s):  
Mohamed Saied Mohamed M.
Keyword(s):  
Biochemical Analysis ◽  
Jugular Vein ◽  
External Jugular Vein ◽  
Iron Chloride ◽  
Blood Samples ◽  
Healthy Cattle ◽  
Internal Parasites ◽  
Effect Of Copper ◽  
Micro Elements ◽  
Average Body

The study was carried out on forty-nine (49) cattle cases were clinically healthy animals with average body condition. They were clinically, and laboratory examined proved as healthy cattle and they are free from internal and external parasites were kept as controls while other one hundred (100) cattle animals were suffering from depraved appetites. All animals were belonged to the villages scattered in the Qena Governorate Egypt. Blood samples were taken from the external jugular vein, and then centrifuged and stored until analyses. Blood was taken aseptically from all the animals and transported to laboratory for biochemical analysis for estimation of macro and micro elements in diseased animals. Fecal samples was taken aseptically from all the animals and transported to laboratory for the presence of internal parasites.  The results showed a highly significant effect of copper, iron, chloride, and sodium significant at (P<0.01), and low significant of protein, zinc, phosphorus and calcium at (P<0. 05). The aim of this work was to follow the changes, during the early diagnosis of depraved appetite on some trace elements, protein and internal parasites.

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