Neurointermediate lobe transplanted under the kidney capsule modifies the activity of the neurointermediate lobe in situ, but does not respond to opiate treatment

1986 ◽  
Vol 64 (4) ◽  
pp. 430-437 ◽  
Author(s):  
Christina Gianoulakis ◽  
Alka Gupta
Keyword(s):  
Pituitary Gland ◽  
Direct Effect ◽  
Anterior Lobe ◽  
Pars Intermedia ◽  
Morphine Treatment ◽  
Kidney Capsule ◽  
Neurointermediate Lobe ◽  
Elevated Content ◽  
Naloxone Treatment

To investigate the possibility of a direct effect of morphine on the pars intermedia cells of the pituitary gland, rat neurointermediate lobes (NIL) were transplanted under the kidney capsule. At 2 and 8 days posttransplantation the NIL transplant had maintained its morphological integrity. However, at 15 days posttransplantation the morphological integrity of the NIL transplant had started to deteriorate. The NIL transplant contained, synthesized, and released β-endorphin-like peptides. It was noticed that there was very little β-endorphin in the radiolabelled biosynthesized products, suggesting that either the maturation processing of proopiomelanocortin was modified, or that β-endorphin was released immediately as soon as it was formed and did not accumulate in the tissue. In support of the latter possibility was the elevated content of β-endorphin-like immunoreactivity in the sera of rats with a NIL under the kidney capsule. Furthermore, the NIL transplant seemed to produce a substance or substances which could decrease the content, the biosynthesis and the release of β-endorphin-like peptides by the NIL in situ. Treatment with either morphine or naloxone for 5 days did not change the β-endorphin-like immunoreactivity content in the NIL transplanted under the kidney capsule. However, a distinct decrease in the β-endorphin-like immunoreactivity in the NIL in situ of animals with or without a NIL transplant was observed following the morphine treatment. Naloxone treatment induced a decrease in the β-endorphin-like immunoreactivity content in the hypothalamus, but had no effect on the β-endorphin-like immunoreactivity content in the anterior lobe and NIL of the pituitary gland in situ or in the NIL transplant.

AUFTRETEN VON KASTRATIONSZELLEN IM HYPOPHYSENVORDERLAPPEN MÄNNLICHER RATTEN NACH BEHANDLUNG MIT EINEM ANTIANDROGEN

1966 ◽  
Vol 53 (1) ◽  
pp. 53-60 ◽  
Author(s):  
F. Neumann
Keyword(s):  
Pituitary Gland ◽  
Inhibitory Effect ◽  
Anterior Lobe ◽  
Male Rats ◽  
Hormone Deficiency ◽  
Pars Intermedia ◽  
Sexual Hormone ◽  
Releasing Factors

ABSTRACT Following the administration of an androgen-antagonist (1,2α-methylene-6-chloro-pregna-4,6-diene-17α-ol-3,20-dione = cyproterone) to male rats, changes are observed in the anterior lobe of the pituitary gland comparable to those which develop following removal of the gonads. The appearance of so called castration cells is very striking, particularly in the periphery, and in the area adjacent to the pars intermedia. The findings suggest that the androgen-antagonism of cyproterone also manifests itself in those receptors of the sex centre, which regulate the amount of gonadotrophin production and secretion in relation to the production of testosterone. Since endogenous testosterone can no longer exert its inhibitory effect on the sex centre, the sex centre, as in a state of sexual hormone deficiency, reacts by secreting releasing factors for gonadotrophins. Thus those cell elements in the anterior lobe of the pituitary gland are stimulated and this leads to the production of gonadotrophin.

Vasopressin uptake by hypothalamopituitary axis and pineal gland in guinea pigs

1991 ◽  
Vol 260 (4) ◽  
pp. E633-E640 ◽  
Author(s):  
B. V. Zlokovic ◽  
S. Hyman ◽  
J. G. McComb ◽  
G. Tang ◽  
A. R. Rezai ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Pituitary Gland ◽  
Maximum Velocity ◽  
Anterior Lobe ◽  
Peptide Fragments ◽  
Central Effects ◽  
Diffusion Constants ◽  
Specific Uptake ◽  
Uptake Mechanisms

The uptake of circulating arginine vasopressin (AVP) by the pituitary gland (anterior lobe), pineal gland, and hypothalamus (ventromedial part) was investigated in an isolated in situ perused brain of anesthetized guinea pig. Kinetic experiments revealed saturable AVP uptake in all studied regions with Km values of 0.79, 0.19, and 0.76 microM and maximum velocity values of 22, 2.1, and 1.6 pmol.min-1.g-1 for the pituitary gland, pineal gland, and hypothalamus, respectively. The nonsaturable components (diffusion constants) were not significantly different from zero. Peptide fragments, L-phenylalanine, and Bestatin (an aminopeptidase inhibitor) did not interfere with AVP uptake. However, uptake of AVP was strongly inhibited in the presence of the V1 antagonist [1-(beta-mercapto-beta-beta-cyclopentamethylenepropionic acid), 2-(O-methyl)tyrosine]AVP at 2.7 microM, and regional Ki values, assuming that the observed inhibitions were purely competitive, ranged between 0.32 and 2.23 microM. The V2 agonist 1-desamino-8-D-AVP at 2.7 microM produced only a weak inhibition of AVP uptake, and regional Ki values ranged between 9.56 and 21.3 microM. It is concluded that specific uptake mechanisms in the hypothalamopituitary axis and pineal gland are sensitive enough to detect blood-borne AVP under the physiological hormonal state. It is suggested that AVP binding in situ is primarily related to V1 receptors, which may be involved in mediating the central effects of this circulating peptide.

AN UNEVEN DISTRIBUTION OF CHOLINE ACETYLTRANSFERASE ACTIVITY IN THE PITUITARY NEUROINTERMEDIATE LOBE OF THE RAT

1980 ◽  
Vol 85 (3) ◽  
pp. 497-501 ◽  
Author(s):  
MARIA G. P. GALLARDO ◽  
M. A. CANNATA ◽  
J. H. TRAMEZZANI
Keyword(s):  
Pituitary Gland ◽  
Choline Acetyltransferase ◽  
Cholinergic System ◽  
Male Rats ◽  
Uneven Distribution ◽  
Pars Intermedia ◽  
Junction Area ◽  
Acetyltransferase Activity ◽  
Neurointermediate Lobe ◽  
Choline Acetyltransferase Activity

The neurointermediate lobe of the pituitary gland of male rats was assayed for choline acetyltransferase (CAT) activity. Precise microsample punches were obtained from neurohypophysial tissue, pure pars intermedia tissue and from the junction area between them. The level of CAT activity (pmol/h per μg protein) in the neurohypophysis, pars intermedia and junction area were 0·390 ± 0·038 (s.e.m.), 0·228 ± 0·042 and 1·824 ± 0·268 respectively. These values show an uneven distribution of CAT in the neurointermediate lobe. The hypothesis of a cholinergic system located in the junction area has been advanced.

Ontogeny of pro-opiomelanocortin (POMC) gene expression and translated products adrenocorticotrophin (ACTH) and α-melanocyte stimulating hormone (α-MSH) in the ovine fetal pituitary gland

1998 ◽  
Vol 10 (3) ◽  
pp. 233 ◽  
Author(s):  
D. M. Hagan ◽  
A. N. Brooks
Keyword(s):  
Pituitary Gland ◽  
Mrna Expression ◽  
Pars Intermedia ◽  
Basal Region ◽  
Melanocyte Stimulating Hormone ◽  
Pituitary Development ◽  
Pomc Mrna ◽  
Ovine Fetal ◽  
Stimulating Hormone

This study sought to determine the ontogeny of pro-opiomelanocortin (POMC) mRNA by in situ hybridization, and the expression of α–melanocyte stimulating hormone (α-MSH) and adrenocorticotrophin (ACTH) by immunohistochemistry, in the ovine fetal pituitary gland. Detection of POMC mRNA, and of ACTH and α-MSH immunoreactivity was first noted at Day 40 of gestation in the pars intermedia (PI) and the pars distalis (PD). After Day 70, α-MSH immunoreactivity was confined to the PI whereas POMC mRNA and ACTH immunostaining remained in both the PI and the PD. Increases (P < 0.05) of POMC mRNA expression were observed in the PI between Days 50–70 and levels then remained constant to Day 141 (term, 145 days). In the basal region of the PD, POMC mRNA expression was high at Day 40, declined (P < 0.01) by Day 50 and then increased progressively to Day 141 of gestation. The proportion of ACTH-immunopositive cells in the PD also fell from 14% at Day 40 to 11.4% at Day 70 and then increased to 15.3% by Day 141. In contrast, neither the level of POMC mRNA expression nor the percentage of corticotrophs changed in the region of the PD immediately adjacent to the PI. These data provide evidence for differential processing of POMC in a tissue-specific manner during early fetal pituitary development.

ON THE SECRETION OF CORTICOTROPHIN BY THE HOMOTRANSPLANTED PITUITARY GLAND IN THE RAT

1962 ◽  
Vol 39 (3) ◽  
pp. 371-384 ◽  
Author(s):  
Roger Foster ◽  
I. Rothchild
Keyword(s):  
Ascorbic Acid ◽  
Pituitary Gland ◽  
Male Rats ◽  
Unilateral Adrenalectomy ◽  
Kidney Capsule ◽  
Ether Anaesthesia ◽  
Pituitary Glands ◽  
Releasing Process ◽  
Acth Release

ABSTRACT Ten week old male rats bearing pituitary gland homotransplants beneath the kidney capsule (transplanted 3 weeks previously) were hypophysectomized 24 hours prior to testing the transplant's ability to release corticotrophin (ACTH). Adrenal ascorbic acid depletion was used as the measure of ACTH release following the stimuli of ether anaesthesia and unilateral adrenalectomy, or these two stimuli, plus intravenous histamine. No significant adrenal ascorbic acid depletion occurred in such animals either 1 or 4 hours after these stimuli. The same results were obtained in rats that were hypophysectomized at the time of pituitary transplantation (7 weeks of age) and tested 3 weeks later. The transplanted pituitary glands contained ACTH at a concentration equivalent to that of the in situ glands. The rats bearing in situ as well as transplanted anterioi pituitary glands until 24 hours prior to autopsy had adrenal weights slightly but significantly heavier than comparable non-transplant-bearing animals. The results suggest that transplantation of the adenohypophysis beneath the kidney capsule interferes with an ACTH releasing process which is most likely mediated primarily through a direct connection with the CNS. The possibility that the slightly heavier adrenals in the transplant bearing animals might be due to a non-ACTH factor secreted by the transplant was also considered.

scholarly journals GABA UPTAKE BY GAT1 MODULATES LONG-TERM OPTICAL CHANGES FOLLOWING ELECTRICAL STIMULATION OF THE PITUITARY GLAND NEUROINTERMEDIATE LOBE

2013 ◽  
Vol 06 (03) ◽  
pp. 1350020
Author(s):  
P. KOSTERIN ◽  
A. L. OBAID ◽  
B. M. SALZBERG
Keyword(s):  
Light Scattering ◽  
Pituitary Gland ◽  
Chloride Channels ◽  
Optical Response ◽  
Pars Intermedia ◽  
Full Time ◽  
S Wave ◽  
Neurointermediate Lobe ◽  
Long Duration ◽  
Stimulation Of

Intrinsic optical changes that follow infundibular stalk stimulation of the neurointermediate lobe of the mouse pituitary gland exhibit three different phases that reflect three distinct physiological events. The first (E-wave) is the rapid light-scattering increase that is associated with a nerve terminal volume increase (mechanical spike), and that accompanies excitation of the neurohypophysial terminals by the invading action potential; the second (S-wave) is the slower light-scattering decrease that is tightly correlated with the secretion of the peptide hormones oxytocin and arginine vasopressin, and the third is the long-duration response (R-wave) that reflects cell volume changes in the pars intermedia. We have studied the E-wave and the S-wave in earlier publications. The R-wave, considered here, is sensitive to chloride replacement as well as to blockade of chloride channels. By blocking GABAA receptors (which are ligand-gated chloride channels) with pharmacological agents, and by applying GABA directly into the bathing solution, or evoking its release from GABAergic inputs, we have demonstrated that this long-duration optical response is sensitive to chloride movements and reflects GABA-induced changes in the intrinsic optical properties of the pars intermedia. The full time-course of this optical response takes minutes and, therefore, has to embody some other process (or processes) related to the restoration of resting physiological chloride concentrations, following the opening and closing of GABAA-receptor channels. Here we demonstrate that the shape of the R-wave, the long-lasting light-scattering signal, is indeed affected by the activity of GAT1, one of the sodium- and chloride-dependent GABA transporters.

Regulation by ovarian factors of the LHRH-induced LH response in pituitary glands in situ or grafted under the kidney capsule in intact and ovariectomized rats

1989 ◽  
Vol 123 (1) ◽  
pp. 41-45 ◽  
Author(s):  
J. A. M. J. van Dieten ◽  
J. de Koning ◽  
G. P. van Rees
Keyword(s):  
Pituitary Gland ◽  
High Rate ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Lag Phase ◽  
Kidney Capsule ◽  
Pituitary Glands ◽  
Lh Release ◽  
Secretory Products

ABSTRACT When pituitary glands from intact female rats are incubated with LHRH, the resulting LH release shows a biphasic pattern: an initial low rate of LH release (lag phase) is followed by a high rate. When pituitary glands from long-term ovariectomized rats are incubated, the rate of LH release is high throughout stimulation with LHRH. The disappearance of the lag phase might be due to increased LHRH release after ovariectomy and/or the disappearance of ovarian factors. To distinguish between these possibilities, pituitary glands which had been exposed to endogenous LHRH (pituitary glands in situ) or which had been unexposed to endogenous LHRH (pituitary glands transplanted under the kidney capsule) were incubated in the presence or absence of LHRH. Biphasic LH secretion patterns were observed during incubation with LHRH with the animal's own pituitary gland and with the transplanted pituitary gland from intact, but not from ovariectomized rats. Thus the disappearance of the lag phase after ovariectomy results from the absence of ovarian secretory products, rather than from increased release of LHRH. Journal of Endocrinology (1989) 123, 41–45

Demonstration of desacetyl α-melanocyte-stimulating hormone in fetal and adult human anterior pituitary corticotrophs

1989 ◽  
Vol 120 (3) ◽  
pp. 525-NP ◽  
Author(s):  
P. J. Coates ◽  
I. Doniach ◽  
J. M. P. Holly ◽  
L. H. Rees
Keyword(s):  
Pituitary Gland ◽  
High Performance ◽  
Anterior Lobe ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Human Pituitary ◽  
Human Pituitary Gland ◽  
Melanocyte Stimulating Hormone ◽  
Pars Anterior ◽  
Human Anterior Pituitary

ABSTRACT Immunocytochemistry, radioimmunoassay and high-performance liquid chromatography (HPLC) techniques have been used in combination to investigate the presence of immunoreactive (ir)-α-MSH in the normal human pituitary gland, and to investigate the possible origin of these cells from the fetal pars intermedia. Two separate antisera to α-MSH were employed in immunocytochemistry to distinguish between authentic α-MSH and the desacetyl form. Only desacetyl α-MSH was detected in the pituitary gland of fetal and adult man, in both the pars (zona) intermedia and the pars anterior. In the fetus, a large proportion of the ACTH-containing cells of the anterior lobe also contained ir-α-MSH, while ir-α-MSH containing cells were more sparse in adults. Radioimmunoassay of acid extracts of adult pituitary tissue showed α-MSH levels representing less than 0·05% of the ACTH content of the gland. HPLC analysis of these extracts confirmed that only the desacetyl form was present. These results suggest that α-MSH peptides are synthesized by anterior lobe cells of the human pituitary gland, which are not derived from the fetal pars intermedia. Possible regulatory mechanisms affecting cells which contain ir-α-MSH are discussed, and by comparison with the intermediate lobe of other species it is concluded that there is little evidence for a true intermediate lobe in the human pituitary gland. Journal of Endocrinology (1989) 120, 525–530

CHANGES IN THE VOLUME OF THE LOBES OF THE PITUITARY GLAND AND IN THE WEIGHT AND WATER CONTENT OF ORGANS OF RATS GIVEN HYPERTONIC SALINE

1968 ◽  
Vol 41 (4) ◽  
pp. 593-600 ◽  
Author(s):  
L. W. DUCHEN
Keyword(s):  
Body Weight ◽  
Sodium Chloride ◽  
Pituitary Gland ◽  
Water Content ◽  
Hypertonic Saline ◽  
Marked Reduction ◽  
Anterior Lobe ◽  
Pars Intermedia ◽  
Posterior Lobe

SUMMARY The volume of the various lobes of the pituitary gland were measured in rats which were given 2% sodium chloride to drink instead of water. The volume of the posterior lobe was increased by 60% after 11 days on saline. The volume of the anterior lobe was slightly decreased but the volume of the pars intermedia was not changed. There was a marked loss of body weight in animals which were given saline and a marked reduction in the weight of the whole pituitary, liver and thyroid.

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