EFFECTS OF MEDIAL HYPOTHALAMIC DEAFFERENTATION ON PROLACTIN SECRETION IN PSEUDOPREGNANT RATS

1978 ◽  
Vol 89 (3) ◽  
pp. 425-431 ◽  
Author(s):  
H. Kato ◽  
M. E. Velasco ◽  
I. Rothchild
Keyword(s):  
Prolactin Level ◽  
Preoptic Area ◽  
Prolactin Secretion ◽  
Anterior Hypothalamus ◽  
Corpora Lutea ◽  
Sham Operation ◽  
Posterior Half ◽  
Night Time ◽  
Hypothalamic Deafferentation

ABSTRACT Frontal hypothalamic deafferentation (FHD), which disconnects the anterior hypothalamus from the preoptic area, stops the twice daily surges of prolactin secretion of pregnancy or pseudopregnancy in the rat, and causes rapid luteolysis. Medial hypothalamic deafferentation (MHD), which separates the anterior from the posterior half of the hypothalamus, does not interrupt pregnancy and causes a significant increase in the size of the corpora lutea. To see whether MHD induces an increase in the basal level of prolactin secretion and/or a change in the pattern of prolactin surges, pseudopregnant rats were subjected to MHD or a sham operation on day 3 (day 1 = day of oestrus) and their bloods assayed for prolactin on either day 5 or days 7–8. MHD caused a specific disappearance of the day-time prolactin surge and a diminution in the height of the night-time surge, but no change from the controls in the basal prolactin level. In spite of what thus appears to be a lesser secretion of prolactin than in the controls, the corpora lutea of the MHD rats were larger, and progesterone was secreted at a higher rate and for a longer time, than in the controls. The relation of these findings to the existence of a "surge centre" in the hypothalamus was discussed.

THE ROLE OF THE HYPOTHALAMUS IN THE TONIC SECRETION OF PROLACTIN INDUCED BY OESTROGENS IN THE RAT

1978 ◽  
Vol 89 (3) ◽  
pp. 417-424 ◽  
Author(s):  
H. Kato ◽  
M. E. Velasco ◽  
I. Rothchild
Keyword(s):  
Prolactin Level ◽  
Direct Action ◽  
Female Rats ◽  
Sham Operation ◽  
Posterior Half ◽  
Optic Chiasma ◽  
Hypothalamic Deafferentation ◽  
Vehicle Treatment ◽  
Group A

ABSTRACT To investigate where oestrogens act to induce an increase in the tonic release of prolactin, the effect of ovariectomy alone or of ovariectomy plus oestradiol benzoate treatment (10 μg/day for 7 days) (OeB10) on the morning prolactin serum level in adult female rats was determined after each of the following procedures: frontal hypothalamic deafferentation (FHD) (a semi-lunar cut at the caudal border of the optic chiasma, separating the anterior hypothalamus from the preoptic area); medial hypothalamic deafferentation (MHD) (a similar cut, but separating the anterior from the posterior half of the hypothalamus); sham deafferentation; an electrolytic lesion of the arcuate-median eminence area (Arcuate-ME lesion); hypophysectomy and pituitary autotransplantation beneath the kidney capsule. The rats were ovariectomized 1 week after the latter procedure, or 3 weeks after the others, and OeB10 or oil vehicle treatment was begun one week after ovariectomy. FHD, the Arcuate-ME lesion and pituitary autotransplantation markedly increased the basal prolactin level; MHD induced a much smaller increase. The level fell after ovariectomy only in the FHD group. A sharp and equal increase in the prolactin level occurred in the FHD, MHD and sham operation groups in response to OeB10; a much smaller and more variable increase occurred in the Arcuate-ME and pituitary autotransplantation groups. The results suggest that oestrogens increase the tonic release of prolactin only in part by a direct action on the pituitary, and more importantly by acting on the posterior half of the hypothalamus or on areas with lateral, superior, or posterior afferent connections to this site.

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

Indomethacin treatment prevents prolactin-induced luteolysis in the rat

1987 ◽  
Vol 112 (2) ◽  
pp. 317-322 ◽  
Author(s):  
J. E. Sánchez-Criado ◽  
K. Ochiai ◽  
I. Rothchild
Keyword(s):  
Corpus Luteum ◽  
Left Kidney ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Silicone Elastomer ◽  
Serum Prolactin ◽  
Corpora Lutea ◽  
Synthesis Inhibitor ◽  
Significant Difference ◽  
Indomethacin Treatment

ABSTRACT Adult female rats were hypophysectomized and their pituitary glands autotransplanted beneath the left kidney capsule on day 2 (day 1 was the day of ovulation). In such rats the pituitary secretes prolactin fairly constantly and the corpora lutea secrete progesterone for several months. To induce the luteolytic effect of prolactin the rats were first injected s.c. with 2-bromo-α-ergocryptine (CB-154) on cycle days 12, 13 and 14 (i.e. 10, 11 and 12 days after operation) to depress prolactin secretion, and then with CB-154 vehicle (70% ethanol) daily until cycle day 21, to allow prolactin secretion to resume. One ovary was removed from each rat on day 15 and the remaining one on day 22. The mean (± s.e.m.) weight of the corpora lutea on day 15 was 1·46±0·06 mg and 0·98±0·07 mg on day 22 (n = 17). In contrast, rats in which the CB-154 treatment was maintained to day 21 had corpora lutea which weighed 1·31 ±0·09 on day 15 and 1·47 ±0·08 mg on day 22 (n = 15). To investigate whether indomethacin, a prostaglandin synthesis inhibitor, affected the luteolytic action of prolactin, the experiment was repeated, but on day 15 (after the removal of one ovary) the groups in which CB-154 treatment was stopped, as well as the group in which CB-154 treatment was maintained, were each divided into two groups. In one, indomethacin-containing silicone elastomer wafers and, in the other, blank silicone elastomer wafers, were placed within the bursa of the remaining ovary. There were no differences in corpus luteum weight on day 15 among any of these groups and the two groups of the first experiment. There was no significant difference in corpus luteum weight between day 15 and day 22 in any of the six groups except for the two groups treated with the CB-154 vehicle and not with indomethacin. Thus, treatment with indomethacin prevented the fall in corpus luteum weight associated with the discontinuation of CB-154 treatment. Serum prolactin levels fell until day 15 in all rats and remained low in those in which the CB-154 treatment was maintained to day 21, but returned to control values in those treated with vehicle after day 14. Serum progesterone levels fell and remained low in all groups. Indomethacin treatment had no effect on the levels of either serum prolactin or progesterone. We conclude that some of the pharmacological effects of indomethacin are to prevent prolactin-induced luteolysis, and we suggest that prolactin induces rapid regression of the corpus luteum by stimulating intraluteal prostaglandin production or by being necessary for the effect of luteolytic prostaglandins. J. Endocr. (1987) 112, 317–322

OVULATORY DISCHARGE OF GONADOTROPHINS INDUCED BY HYPOTHALAMIC STIMULATION IN CASTRATED MALE RATS BEARING A TRANSPLANTED OVARY

1966 ◽  
Vol 51 (2) ◽  
pp. 281-289 ◽  
Author(s):  
J. Moll ◽  
G. H. Zeilmaker
Keyword(s):  
Electrical Stimulation ◽  
Preoptic Area ◽  
Hypothalamic Stimulation ◽  
Male Rats ◽  
Corpora Lutea ◽  
Histological Changes ◽  
Experimental Animals ◽  
Cumulus Oophorus ◽  
Dc Current ◽  
Stimulation Of

ABSTRACT Castrated young adult inbred male rats bearing ovarian transplants were subjected to electrical stimulation of the hypothalamus. This was done in order to investigate whether discharge of ovulatory amounts of gonadotrophins could be induced in such male animals by this procedure. Bilateral stimulations with unipolar electrodes and a DC current of 1.5 mA applied during 10 seconds induced in the ovarian grafts histological changes indicating the discharge of ovulatory amounts of gonadotrophins. In animals killed one day after stimulation these changes consisted of displacement of the ova towards the centre of the follicles with loosening of the cumulus oophorus. In one animal the ova had left the follicles. In animals killed three days after stimulation numerous young corpora lutea could be observed. These results were obtained with electrode tips either close to the median eminence, or in the preoptic area. Shamstimulations were ineffective. Some of the experimental animals received progesterone pretreatment. This rendered the stimulations ineffective, if continued until the day preceding stimulation, but seemed without effect on the results of stimulation, if two or three days without progesterone preceded the stimulations.

REDUCTIVE PATHWAYS OF PROGESTERONE METABOLISM IN THE RAT OVARY

1972 ◽  
Vol 69 (1) ◽  
pp. 141-152 ◽  
Author(s):  
A. Zmigrod ◽  
H. R. Lindner ◽  
S. A. Lamprecht
Keyword(s):  
Hydroxysteroid Dehydrogenase ◽  
Prolactin Secretion ◽  
Ovariectomized Rats ◽  
Corpora Lutea ◽  
Microsomal Preparation ◽  
Progesterone Metabolism ◽  
Rat Ovary ◽  
Reducing Activity ◽  
Pituitary Prolactin

ABSTRACT Progesterone underwent extensive reductive metabolism when incubated with a microsomal preparation from rat ovaries in the presence of NADPH. The major products formed were 3β-hydroxy-5α-pregnan-20-one, 5α-pregnane-3,20-dione and 5α-pregnane-3β,20α-diol. Newly formed corpora lutea of pregnancy were almost devoid of any microsomal A-ring reducing activity (5α-reductase and a 3β-hydroxysteroid dehydrogenase) and of soluble 20α-hydroxysteroid dehydrogenase. The behaviour of the A-ring reducing enzymes paralleled that of 20α-ol dehydrogenase in that their activity (i) was high during the oestrous cycle; (ii) declined between the third and seventh day of pregnancy; and (iii) increased sharply in corpora lutea of pregnancy when ergocornine – a drug blocking pituitary prolactin secretion – was given to the rats, yet remained low when prolactin and ergocornine were administered concurrently. However, the A-ring reducing activity did not show the sharp pre-partum rise exhibited by 20α-ol dehydrogenase, thus deviating from a pattern compatible with a co-ordinate control of the three enzymes involved in the metabolic inactivation of progesterone. Contrary to a report in the literature, 5α-pregnane-3,20-dione (20 mg/rat/day) was found to be ineffective when tested for pregnancy or deciduoma supporting activity in ovariectomized rats. The microsomal reductases, if indeed operative in vivo, may restrict the availability of progesterone as an oestrogen precursor.

Danazol and prolactin status in patients with endometriosis

1984 ◽  
Vol 107 (4) ◽  
pp. 445-449 ◽  
Author(s):  
A. M. Wallace ◽  
D. A. R. Lees ◽  
A. D. G. Roberts ◽  
C. E. Gray ◽  
E. H. McLaren ◽  
...  
Keyword(s):  
Prolactin Level ◽  
Prolactin Secretion ◽  
Normal Serum ◽  
Serum Prolactin ◽  
Serum Prolactin Level ◽  
Significant Drop ◽  
Increased Sensitivity ◽  
Danazol Therapy

Abstract. A group of 55 women with endometriosis was studied before and during danazol therapy. An unexpectedly high proportion (36%) had a raised serum prolactin level before treatment which was reduced after 50 days of danazol (before treatment 783 ± 333 mU/l; on danazol 243 ± 113 mU/l, P < 0.001). In contrast patients with normal serum prolactin levels showed no significant drop on danazol therapy. In all patients serum oestradiol was significantly reduced during treatment (before treatment 449 ± 188 pmol/l; on danazol 207 ± 117 pmol/l, P < 0.001). In one patient with hyperprolactinaemia danazol reduced both basal and stimulated prolactin levels, whereas in 5 women with normal prolactin levels we could detect no gross alteration in metoclopramide or TRH stimulated prolactin levels associated with danazol therapy. The possibility that normalisation of raised prolactin levels may be secondary to reduced oestrogens and that patients with endometriosis have an increased sensitivity to oestrogen-induced prolactin secretion is discussed.

Central administration of interleukin 1 elicits hyperinsulinemia in rats

1989 ◽  
Vol 256 (3) ◽  
pp. R772-R777 ◽  
Author(s):  
R. P. Cornell ◽  
D. B. Schwartz
Keyword(s):  
Insulin Secretion ◽  
Preoptic Area ◽  
Interleukin 1 ◽  
Experimental Period ◽  
Anterior Hypothalamus ◽  
Saline Control ◽  
Central Administration ◽  
Major Question ◽  
Control Value ◽  
The Central Nervous System

This laboratory previously demonstrated that human natural interleukin 1 (IL-1) administered intravenously at a dose of 50 U to conscious fasted male Holtzman rats elicited unstimulated as well as glucose- and arginine-stimulated hyperinsulinemia. The major question posed in the present investigation is whether the monokine IL-1 can act centrally on an area of the brain such as the preoptic area of the anterior hypothalamus, which participates in mediating the IL-1-induced febrile response, to elicit insulin secretion by the pancreas. Therefore, for this study, injections of IL-1 were administered intravenously (iv), intracerebroventricularly (icv), or into the preoptic area of the anterior hypothalamus (iPO) in pentobarbital-anesthetized fasted rats. Preliminary experiments determined that the hyperinsulinemic response was enhanced in anesthetized compared with conscious animals treated iv with IL-1. An icv administered 10-U dose of the monokine produced a delayed hyperinsulinemia equal to two times the saline control value starting near 20 min postinjection but declining quickly. When injected iPO, 5 U of IL-1 elicited a prompt substantial hyperinsulinemia equal to more than three times control beginning at 5 min postinjection and persisting through the 30-min experimental period. These findings indicate that an IL-1-induced signal for pancreatic insulin secretion can be generated within the central nervous system.

scholarly journals Ectopic Prolactin Secretion From a Uterine Leiomyoma

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Saachi Sachdev ◽  
Maria Carolina Reyes ◽  
Peter J Snyder
Keyword(s):  
Prolactin Level ◽  
Uterine Leiomyoma ◽  
Prolactin Secretion ◽  
Sellar Mass ◽  
Hormone Production ◽  
Ectopic Production ◽  
First Time

Abstract Ectopic hormone production is well recognized, but ectopic production of prolactin has been reported infrequently. We report here the case of a 47-year-old woman who had hyperprolactinemia (213-224 ng/mL) causing galactorrhea and hypogonadism. Cabergoline treatment, 1.0 mg twice a week, did not lower the prolactin level at all, but excision of a large uterine leiomyoma corrected the hyperprolactinemia and the hypogonadism. The excised leiomyoma tissue exhibited immunostaining for prolactin, confirming by this method for the first time that a uterine leiomyoma was the cause of hyperprolactinemia. This case illustrates the need to consider an ectopic source of prolactin in a patient who has hyperprolactinemia that is not associated with a large sellar mass and is completely resistant to cabergoline.

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