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

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

1986 ◽  
Vol 111 (2) ◽  
pp. 335-NP ◽  
Author(s):  
P. J. Coates ◽  
I. Doniach ◽  
A. C. Hale ◽  
L. H. Rees

ABSTRACT It has been suggested that a proportion of the adenomas and the nodular hyperplasia of cells in the pituitary gland in cases of Cushing's disease are derived from cells of the pars intermedia rather than the pars anterior. The evidence can be summarized as follows: (1) the posterior site of adenoma or nodular hyperplasia in the pituitary, (2) the innervation of cells and (3) the suppressive response to the dopamine agonist bromocriptine in vivo or to dopamine in vitro. All these observations infer analogy with cells of the pars intermedia of other species, which are controlled by direct neural tonic dopaminergic inhibition. The adult human pituitary gland, however, does not possess a morphologically distinct pars intermedia, due to regression of the rudimentary fetal pars intermedia after birth, with mixing of cells into the pars anterior and pars nervosa. Since cells of the pars intermedia characteristically synthesize α-MSH, we have studied this peptide in order to assess the occurrence and distribution of intermedia-derived cells in the adult human pituitary. Sections from 100 pituitaries, removed at autopsy, were stained by an indirect immunoperoxidase technique using non-cross-reacting antisera specific for α-MSH and ACTH. Immunoreactive α-MSH (IR-α-MSH) cells were found in a total of 97 specimens. Of these, only ten cases showed a marked concentration of IR-α-MSH cells in the zona intermedia. In the majority of pituitaries, IR-α-MSH cells were more commonly seen in the pars anterior than in the zona intermedia; in 41 cases, IR-α-MSH cells were completely absent from the zona intermedia. The number of IR-α-MSH cells varied greatly, from less than ten cells per section to many hundreds, regardless of the age or sex of the individual. Additionally, no correlation could be made between the number of IR-α-MSH cells and the cause of death, treatment or the period of time between death and removal of the pituitary. We conclude that cells containing IR-α-MSH are present in varying numbers in the normal adult human pituitary gland. These cells do not show a specific distribution pattern, but may be found in both the zona intermedia and are spread throughout the pars anterior. J. Endocr. (1986) 111, 335–342


Author(s):  
Eva Horvath ◽  
Kalman Kovacs

The human pituitary gland consists of two major components: the adenohypophysis comprising the hormone producing cells of the pars anterior, pars intermedia, and pars tuberalis, and the neurohypophysis, also called pars nervosa or posterior lobe (1). In contrast to most mammalian species, the human gland has no anatomically distinct pars intermedia (2). The exclusively proopiomelanocortin (POMC)-producing cells of the pars intermedia are sandwiched between the anterior and posterior lobes in the majority of mammals, whereas in the human they are incorporated within the pars anterior, thereby constituting the pars distalis (3). The pars tuberalis is a minor upward extension of the adenohypophysis attached to the exterior of the lower pituitary stalk. In this chapter we deal only with adenohypophyseal tumours. Histologically, the adenohypophysis consists of a central median (or mucoid) wedge flanked by the two lateral wings. The hormone-producing cell types are distributed in an uneven, but characteristic manner. The cells are arranged within evenly sized acini surrounded by a delicate but well-defined reticulin fibre network giving the pituitary its distinct architecture (4). In the center of the acini is the long-neglected pituitary follicle composed of the agranular nonendocrine folliculo-stellate cells (5).


1936 ◽  
Vol s2-78 (312) ◽  
pp. 637-651
Author(s):  
N. H. HOWES

1. The structure of the pituitary of the adult skate is described. 2. This gland shows two distinct regions of growth which can be correlated with increase of size of the animal. 3. The pars anterior can be subdivided into three regions differing by the staining reactions of their constituent cells: (a) an anterior region where deep-purple chromaphil cells are found; (b) a middle, where they are faintly basiphil; and (c) a posterior, where they are mainly acidophil. 4. It is suggested that these regions are homologous with the pars tuberalis, basiphil, and oxyphil areas respectively of the pars anterior of the mammalian pituitary. 5. The oxyphil cells show an iodine-leucobase reaction similar to that given by the oxyphil cells of the ox pituitary. 6. The ventral lobe is a completely separate structure from the pars intermedia, although it may run along the ventral surface of the latter for some distance. 7. The histology of the neuro-intermediate lobe is described.


1961 ◽  
Vol 37 (4) ◽  
pp. 479-510 ◽  
Author(s):  
H. L. Sheehan ◽  
J. P. Stanfield

ABSTRACT From a histological study of the lesions which develop in the vessels of the human pituitary gland during the first two days after the onset of post-partum necrosis of the anterior lobe, it is concluded that the primary vascular disturbance is a spasm involving the arteries which supply the anterior lobe and the stalk. This arrests the portal blood supply and also the direct arterial blood supply to the lobe, but permits a slight circulation to continue in the stalk. If the spasm is relieved within about an hour the parenchyma suffers only a transient functional damage. If it continues for several hours all the tissues in the anterior lobe are killed and, when blood finally attempts to flow into the dead vessels, stasis and thrombosis occurs. This thrombosis is a secondary phenomenon and is not the cause of the necrosis. Variations in the extent and the duration of the spasm account for the variations in the size of the necrosis; in about half the cases the lesion involves 97 to 99 per cent of the anterior lobe, but the pars tuberalis and a small amount of the pars interloralis always survive. The arterial spasm is certainly related to a severe general circulatory collapse at the time of delivery, but the reason for its very specific localisation to the anterior lobe of the pituitary gland remains obscure.


1961 ◽  
Vol 36 (2) ◽  
pp. 185-196 ◽  
Author(s):  
A. R. Currie ◽  
J. B. Dekanski

ABSTRACT Human anterior pituitary glands collected at autopsy within 6 hours of death were investigated for gonadotrophic and lactogenic activity. The glands were extracted with 2 % saline and most of the gonadotrophic and lactogenic activity appears to be extracted by this procedure. Little corticotrophic and thyrotrophic activity was found in the extract. The yield of extractable gonadotrophin in the pituitary glands of males and females of varying ages, and the effect of ovariectomy (in two cases) and of cortisone therapy (in one case) on the yield have been investigated. A reference preparation for human menopausal gonadotrophin (HMG20A, Organon) was used as a standard. The amount of stored gonadotrophin increased with advancing age in both sexes. Ovariectomy was associated with a higher yield and cortisone therapy with a lower yield than that shown in pooled pituitary glands from women of the same age group. The ratio of the biological activity of FSH to ICSH in the pituitary glands of men over the age of 50 was about 1 : 1. The method of assay for prolactin was semi-quantitative but there was the same general trend of increased yield with advancing age. The pituitary gland from the case treated with cortisone had the highest yield while ovariectomy appeared to result in a decrease in the stored amount of the hormone. The functional significance of the results of the yield of stored hormones in the human pituitary gland is briefly discussed.


1974 ◽  
Vol 87 (3) ◽  
pp. 414-426 ◽  
Author(s):  
K. Kovacs ◽  
E. Horvath ◽  
I.E. Stratmann ◽  
C. Ezrin

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