Distribution and number of gonadotrophic cells in the pituitary gland of prepubertal female rats

1982 ◽  
Vol 94 (3) ◽  
pp. 381-NP ◽  
Author(s):  
H. G. Jansen
Keyword(s):  
Light Microscopy ◽  
Pituitary Gland ◽  
Unit Volume ◽  
Cell Number ◽  
Female Rats ◽  
Pars Distalis ◽  
Pituitary Tissue ◽  
Lh Cells ◽  
Gonadotrophic Cells

The localization and number of LH- and FSH-containing cells (LH cells and FSH cells) in the pituitary gland of prepubertal female rats aged 5, 10, 15, 20, 25 and 30 days were determined by means of immunocytochemical light microscopy of 5 μm horizontal sections. Anti-rat LHβ and anti-rat FSHβ were used in combination with the unlabelled peroxidase–antiperoxidase method. The gonadotrophic cells were regularly distributed throughout the pars distalis but at 5 and 10 days of age fewer LH and FSH cells were found in lateral regions. The numbers of LH and FSH cells per pituitary gland increased with age. The number of LH cells per unit volume of pituitary tissue reached a maximum at 20 days; the number of FSH cells reached a maximum at 15 days and then decreased with increasing age. At all ages except 5 days more LH than FSH cells were counted per unit volume. Some cells reacting with both anti-rat LHβ and anti-rat FSHβ were detected. Comparison of the data obtained on the dynamics of cell number with data previously obtained on pituitary gonadotrophin content suggests that at successive prepubertal ages LH and FSH cells contain increasing amounts of their respective hormones.

GONADOTROPHIC AND THYROTROPHIC CELLS OF THE PITUITARY GLAND OF THE FERRET

1963 ◽  
Vol 25 (4) ◽  
pp. 495-503 ◽  
Author(s):  
R. L. HOLMES
Keyword(s):  
Pituitary Gland ◽  
Alcian Blue ◽  
Seasonal Variations ◽  
Regional Distribution ◽  
Pars Distalis ◽  
Gonadotrophic Cells

SUMMARY The regional distribution of types of cell in the pars distalis of the ferret's pituitary gland has been described. Seasonal variations in cytology, and the effect of thyroidectomy and gonadectomy have been studied. The gonadotrophic cells contain coarse PAS-positive granules, and are distributed widely throughout the gland. In anoestrous animals they are poorly granulated, and become almost totally degranulated after ovariectomy. PAS-positive cells which also stain with Alcian blue appear to be thyrotrophic in function, and become degranulated after thyroidectomy. They occur throughout most of the gland, but especially in ventral and rostro-lateral regions. Pregnancy, or treatment of ovariectomized animals with oestrogen, is followed by the appearance of numerous cells equivalent to the 'carminophils' of the cat.

Possible role of dopamine and noradrenaline in the regulation of prolactin secretion from an ectopic anterior pituitary gland in female rats

1987 ◽  
Vol 113 (1) ◽  
pp. 45-49 ◽  
Author(s):  
J. J. Fernández-Ruiz ◽  
M. Cebeira ◽  
C. Agrasal ◽  
J. A. F. Tresguerres ◽  
A. Bartke ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Plasma Prolactin ◽  
Noradrenaline Content ◽  
Pituitary Tissue ◽  
Dopamine Content ◽  
And Control

ABSTRACT It was recently reported that anterior pituitary tissue transplanted to an ectopic site contains measurable amounts of dopamine and noradrenaline. To examine the possibility of local catecholaminergic control of prolactin secretion from ectopic pituitaries, pituitary grafted and sham-operated female rats were submitted to several pharmacological treatments modifying catecholamine synthesis. Administration of a single dose of α-methyl-p-tyrosine (α-MPT) significantly reduced dopamine content in the graft, while noradrenaline content was not modified. Similar changes in the contents of dopamine and noradrenaline after α-MPT administration were observed in the hypothalamus and in the in-situ pituitary in both grafted and sham-operated rats. Plasma concentrations of prolactin were increased in both grafted and sham-operated rats after administration of α-MPT. A single injection of l-3,4-dihydroxyphenylalanine (l-DOPA) increased dopamine content in the ectopic pituitary gland without altering the noradrenaline content, and produced similar effects in the hypothalamus and in-situ pituitary of grafted and control rats. Plasma prolactin concentrations were decreased by l-DOPA in both pituitary grafted and control rats. Administration of dl-treo-dihydroxyphenylserine (DOPS) increased noradrenaline content in the ectopic pituitary and reduced plasma prolactin concentrations in pituitary grafted rats. In contrast, injection of DOPS to control rats increased both hypothalamic noradrenaline content and plasma prolactin concentrations. These results suggest that dopamine and noradrenaline present in the ectopic pituitary tissue have a role in mediating prolactin release from pituitary transplants. J. Endocr. (1987) 113, 45–49

THE PITUITARY AND ADRENAL RESPONSES TO ADMINISTRATION OF OESTRIOL IN GONADECTOMIZED RATS

1961 ◽  
Vol 38 (1) ◽  
pp. 50-58 ◽  
Author(s):  
N. E. Borglin ◽  
L. Bjersing
Keyword(s):  
Pituitary Gland ◽  
Adrenal Cortex ◽  
Clinical Experience ◽  
Uterine Cervix ◽  
Morphological Changes ◽  
Physiological Significance ◽  
Female Rats ◽  
Experimental Conditions ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACT Oestriol (oestra-1,3,5(10)-triene-3,16α,17β-triol) is a weakly oestrogenic substance which, however, in contrast to what was formerly believed, is of physiological significance. Its effect is localized largely to the uterine cervix and vagina. Clinical experience argues both for and against an effect on the pituitary gland. This investigation is concerned with the morphological changes in the pituitary gland and adrenal cortex of gonadectomized male and female rats after the injection of oestriol. It was found that oestriol has the same type of action on these glands as other oestrogens, but under the experimental conditions used, this effect proved much weaker than that produced by oestradiol (oestra-1,3,5(10)-triene-3,17β-diol).

IN-VITRO STUDIES OF THE EFFECTS OF OESTROGEN PRETREATMENT ON THE SENSITIVITY OF THE IMMATURE FEMALE RAT PITUITARY GLAND TO STIMULATION WITH GONADOTROPHIN RELEASING HORMONE

1977 ◽  
Vol 74 (1) ◽  
pp. 11-21 ◽  
Author(s):  
M. WILKINSON ◽  
D. DE ZIEGLER ◽  
DANIELLE CASSARD ◽  
K. B. RUF
Keyword(s):  
Pituitary Gland ◽  
Brain Lesion ◽  
Culture Technique ◽  
Female Rats ◽  
Female Rat ◽  
Immature Female ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Unilateral Brain Lesion

The effects of oestrogen priming on the sensitivity of the anterior pituitary gland to stimulation with gonadotrophin releasing hormone (GnRH) was investigated in immature female rats using a new organ culture technique. Hemipituitary glands obtained from animals primed with a single dose of oestradiol benzoate (OB; 20 μg/100 g body weight) released significantly more LH when pulsed with GnRH (4 nmol/l) than did control hemipituitary glands. This potentiating effect was detectable as early as 5 days after birth. After a second stimulation, LH secretion remained high. These results were compared with those obtained from animals treated to induce increased levels of endogenous oestrogen on day 26 of life. Thus, hemipituitary glands were obtained from animals given two injections of OB, an injection of pregnant mare serum gonadotrophin (PMSG) or a unilateral brain lesion placed in the basal hypothalamus. Pituitary tissue was stimulated as before with a pulse of GnRH. Two injections of OB enhanced the sensitivity to stimulation. Conversely, both PMSG and lesion treatment severely reduced the sensitivity to GnRH, although PMSG-treated and lesioned animals have been used as models for the study of ovulation.

Effects of long-term administration of high doses of medroxyprogesterone acetate on hormone receptors and target organs in the female rat

1984 ◽  
Vol 103 (3) ◽  
pp. 287-293 ◽  
Author(s):  
F. Di Carlo ◽  
S. Racca ◽  
G. Conti ◽  
E. Gallo ◽  
G. Muccioli ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Medroxyprogesterone Acetate ◽  
Prolactin Receptor ◽  
Female Rats ◽  
Serum Prolactin ◽  
Target Organs ◽  
Term Administration ◽  
Pituitary Glands ◽  
High Doses

ABSTRACT The changes in oestrogen, progesterone and prolactin receptor levels in target organs, and the macroscopic and microscopic modifications of uterus, ovary, adrenal and pituitary gland induced by long-term administration of high doses of medroxyprogesterone acetate (MPA) were investigated in female rats. Medroxyprogesterone acetate was injected i.m. for 30 days at daily doses of 7·5, 15 and 75 mg/kg. Oestrogen and/or progesterone-binding capacities were remarkably reduced at all doses of MPA used both in the uterus and pituitary gland. Furthermore, MPA caused a very evident reduction in the weight of pituitary glands, ovaries, adrenals and uterus. In all MPA-treated rats corpora lutea were absent from the ovaries, whereas the adrenals showed a significant reduction in the thickness of the cortex. In accordance with this, there was no evidence of ACTH-producing cells in the pituitary glands. Prolactin-producing cells were also absent, while GH-producing cells were present. Serum prolactin levels were significantly reduced at all doses of MPA used. A dramatic reduction of prolactin receptor concentrations was observed in the liver and the ovaries of MPA-treated rats. The results suggest that MPA acts as an antioestrogenic drug both by reducing the number of oestrogen receptors in target tissues and by changing the structure (and perhaps the function) of those organs (pituitary glands, ovaries and adrenals) which are, directly or indirectly, a source of oestrogens. The decreased synthesis of prolactin and the reduction of the number of prolactin receptors (which, on the contrary, are both increased by oestrogens) might be considered as additional antioestrogenic effects of MPA. J. Endocr. (1984) 103, 287–293

Effect of Starvation on Pituitary and Serum Follicle-Stimulating Hormone and Luteinizing Hormone Following Ovariectomy in the Rat

1972 ◽  
Vol 50 (8) ◽  
pp. 768-773 ◽  
Author(s):  
E. A. Ibrahim ◽  
B. E. Howland
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Follicle Stimulating Hormone ◽  
Female Rats ◽  
Intact Female ◽  
Pituitary Glands ◽  
Ad Libitum ◽  
Stimulating Hormone

The concentration of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in serum and pituitary glands was studied in intact female rats and rats that were ovariectomized on day 0 of the experiment and then starved or fed for 2, 4, 7, or 9 days. Ovariectomy resulted in enhanced rates of synthesis and release of FSH and LH as indicated by the significant (P < 0.01) rises in the concentration of both hormones in the pituitary gland and serum.Starvation resulted in a decrease in body and pituitary weight. The concentration of FSH and LH in pituitary glands of starved rats was higher (P < 0.05) than that in fed rats on days 7 and 9. The concentration of FSH and LH in serum of starved rats was increased after ovariectomy but the levels on days 7 and 9 were lower than those of fed rats.These results suggest that the synthesis of FSH and LH was enhanced in both starved and fed rats following ovariectomy while the rate of release of both hormones was decreased at 7 and 9 days of starvation in comparison with rats fed ad libitum.

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