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M Benjamin

Publications and source records attributed to M Benjamin.

49 records · Page 3Linked to original sources
PubMed1976

Ultrastructural studies on prolactin and growth hormone cells in Anguilla pituitaries in vitro.

Eel hemi-pituitaries were cultured in vitro on high or low sodium media which are known to affect differentially prolactin and growth hormone release. Ultrastructural examination of the prolactin cells after 24 h culture showed the Golgi bodies were markedly more abundant and widely distributed in hemi-pituitaries from the low sodium medium. Secretory granule release profiles and dense bodies were also more frequent, but the percentage of the cytoplasmic volume occupied by secretory granules was lower than on the high sodium medium. RER was only slightly modified. Significant differences were noted in the shape and processes of the non-granulated (stellate) cells of the RPD, but there were only slight differences in the the ultrastructure of the somatotropes.

Anguilla↗
PubMed1976

Ultrastructure of the endocrine cell types in the adenohypophysis of the teleost, Poecilial latipinna--a morphometric model.

A morphometric model providing detailed quantitative information on the ultrastructure of the adenohypophysial endocrine cells has been developed for Poecilia latipinna. The model consists of various morphological components quantified in terms of volumes, surfaces or numbers. For prolactin and growth hormone cells, appropriate results are expressed relative to the average volume of that cell type. The difficulties of quantifying EM data on pituitary glands, together with the various sources of error to which the data are clearly open, have been discussed. Some practical application of quantitative EM to problems in fish pituitary research are outlined.

Animals↗
PubMed1975

Ultrastructure of the adenohypophysis in the teleost Poecilia latipinna.

In the sailfin molly, Poecilia latipinna, seven morphological endocrine cell-types could be distinguished with the electron microscope. Each of these was identified with one of the seven cell-types distinguished with the light microscope, to most of which endocrine functions have previously been allocated. Corticotrophs and prolactin cells form the rostral pars distalis, and the proximal pars distalis consists of an outer layer of gonadotrophs and an inner zone containing growth hormone cells and thyrotrophs. The pars intermedia contains two cell-types, of uncertain function. Stellate cells (interstitial cells) occur throughout the adenohypophysis, but are most numerous and prominent in the rostral pars distalis. The inner proximal pars distalis contains a cell-type not previously distinguished in this species with the light microscope, the Z-cell, which could be aminergic. The ultrastructural features of each cell-type are described in detail, and discussed in comparisons with the homologous cells described in other teleosts. There is good agreement for different teleosts in the ultrastructural details of each cell type.

Adrenocorticotropic Hormone↗
PubMed1975

The adenohypophysis of the flounder, Pleuronectes flesus, and the minnow, Phoxinus phoxinus.

The pituitary gland of the flounder, Pleuronectes flesus, showed several unusual cytological features. Between the RPD and the PPD was a zone of cells that stained purple with Alcian blue--PAS--orange G. Many of these cells were apparently degenerating. In the PPD the strands and coils of presumptive STH cells showed a tremendous variation in both size and staining properties. In the PI there were two cell types, the PAS-positive one bordering the neurohypophysis. Around the periphery of the PI was a zone of chromophobic cells, and throughout the PI were numerous intracellular and extracellular acidophil spheres. No well defined ACTH cells were found in the RPD of the minnow (Phoxinus phoxinus). The Alcian blue--PAS--orange G technique distinguishes between blue TSH cells and purple GTH cells in the RPD and PPD. GTH cells from animals collected in the winter were vacuolated. The PI contained two cell types whose staining reactions and ultrastructure were extremely variable. Intra- and extra-cellular acidophil spheres were present.

Adrenocorticotropic Hormone↗
PubMed1975

Cardiac anoxia tolerance of carbon monoxide-poisoned, hypoxia-exposed and normal rats.

Under nitrogen anoxia heart rate (HR) persists at a high level for 1 min longer in rats exposed chronically to carbon monoxide and hypoxia than in unexposed control rats. Although declining sharply, HR of exposed animals continues higher than HR of controls during min 1-4 of anoxia. However, during min 5 and 6 of anoxia HR of CO-poisoned rats becomes similar to that of controls, while HR of hypoxia-exposed rats remains above control HR for 3 min longer. The data are discussed in light of cardiovascular changes induced by CO and hypobaric hypoxia.

Animals↗