Differentiation of growth hormone‐ and prolactin‐containing acidophils with peroxidase‐labeled antibody

Baker, Burton L.; Midgley, A. Rees; Gersten, Brian E.; Yu, Ya-Yen

doi:10.1002/ar.1091640204

Cited by 72 publications

(19 citation statements)

References 14 publications

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“…Furthermore, studies by Costoff and McShann [5], based on isopycnic gradient centrifugation, demonstrated that 95% of GH biologi cal activity was found in a zone containing secretory granules havlr>g a maximum diameter of 350 nm. These data are supported by immunofluorescence studies of Shiino and Rennets [30] and immunoperoxidase-labeled antibody data [3,17].…”

Section: Identification O F Somatotrophssupporting

confidence: 68%

Structural Correlates of Stimulated and Inhibited Secretion: Electron Microscopic Observations of Somatotrophs in Perifused Rat Pituitary

Stachura

Costoff

Tyler³

1986

Neuroendocrinology

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The in vitro release of stored intracellular rat growth hormone (rGH) in response to several secretagogues suggests the functional division of rGH storage into at least two ‘compartments’ or ‘pools’. The first is an immediately releasable compartment whose response is brief. The second is a compartment which responds to more prolonged secretory demands. These observations are consistent with either a single, homogeneous population of somatotrophs, each of which exhibits functional compartmentalization of storage, or with heterogeneous populations of somatotrophs, each family of which provides one of the observed responses. We sought anatomical correlates of this functional compartmentalization using a perifusion/morphometric system which permitted examination of the first model while not excluding the second model. We selected for study an established perifusion protocol whose behavior was consistent and whose previous results suggested phases of both filling and emptying of the immediate release pool. Five parallel perifusions of pituitary fragments were run. The fifth perifusion was used to monitor rGH release and to confirm that the experiment had behaved in standard fashion. The first pituitary chamber was dismantled during basal perifusion to obtain tissue for microscopy, the next during exposure to 25 nM SRIF, the third during exposure to both 25 nM SRIF and 1 mM (Bu)₂cAMP, and the fourth shortly after the rapid release which followed SRIF withdrawal. Somatotroph granulation was decreased by 54% in the presence of SRIF, and then increased by 45% with the addition of (Bu)₂cAMP. The intracellular distribution of granules also fluctuated in relation to the stimulatory and inhibitory secretagogues. In addition, secondary lysosomes increased by 549% during SRIF-induced inhibition of rGH release. Cell volume was decreased by 37% in the presence of 25 nM SRIF; the addition of (Bu)₂cAMP did not reverse this SRIF effect. We conclude that the in vitro release phenomenon we have termed the ‘immediate release pool’ has an anatomic correlate in juxtamembrane granules, that inhibition of rGH release is accompanied by a significant increase in secondary lysosome activity, that while heterogeneous populations of somatotrophs probably exist, individual cells possess a range of responses consistent with functional compartmentalization, and that rGH release involves not only granule movement between anatomically demonstrable compartments, but in addition, major and rapid changes in somatotroph volume.

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Section: Identification O F Somatotrophssupporting

confidence: 68%

Structural Correlates of Stimulated and Inhibited Secretion: Electron Microscopic Observations of Somatotrophs in Perifused Rat Pituitary

Stachura

Costoff

Tyler³

1986

Neuroendocrinology

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“…2-4) highlight the im pact of the ovary on these two cell types. In the case of mammotrophs, these modifications can be explained by a direct action of estrogens on the AP [16,22,30], Immuno stained mammotrophs were judged larger and more numer ous in adult female rats than in either adult males or ova riectomized females [4]. Estrogens may also have an indirect effect via the hypothalamus: an acute effect of estradiol is to suppress secretion of dopamine into the hypophyseal portal blood [10], which probably results in enhanced mammo troph secretion.…”

Section: Discussionmentioning

confidence: 99%

Mammotroph and Gonadotroph Volume Percentage in the Rat Anterior Pituitary after Lesion of the Medial Basal Hypothalamus

Cronin

Cheung²,

Weiner

et al. 1982

Neuroendocrinology

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A lesion of the medial basal hypothalamus (MBH) results in enhanced secretion of prolactin and reduced release of the other hormones from the anterior pituitary. We measured the volume percentage of the prolactin-secreting mammotrophs, stained immunocytochemically, under several experimental conditions to assess the morphological correlate of the high secretion of prolactin. In addition, gonadotrophs were stained both tinctorially with the periodic acid-Schiff reagent and immunocytochemically with antibodies to luteinizing hormone. Anterior pituitaries were studied from female rats which were:(1) cycling, (2) ovariectomized for 2 weeks, (3) ovariectomized for 2 weeks with a lesion of the MBH for 1. 14 or 21 days. The volume percentage of mammotrophs and gonadotrophs in the lateral, central and middle fields of the anterior pituitary was determined and this measurement was expressed relative to endocrine cellular area so that vascular space and necrotic regions would not be included in the assessment. Ovariectomy significantly decreased mammotroph and increased gonadotroph volume percentage when compared to the intact animal. MBH lesions had the opposite effect. At 14 and 21 days after a lesion, the volume percentage of mammotrophs was significantly greater than in the intact rat, while the volume percentage of gonadotrophs was identical to that observed in the intact rat. These data suggest that the elimination of the prolactin-inhibitory hormone(s) of the MBH results in hypertrophy and/or hyperplasia of mammotrophs. This effect occurs in the absence of ovarian steroids and may be of importance in the induction of prolactin-secreting pituitary adenomas. The data also support the hypothesis that destruction of gonadotropin-releasing hormone neuron terminals countermands the hypertrophy of gonadotrophs induced by ovariectomy.

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“…Only the com parison w ith the lightm icroscopy image obtained from a th ick section of th e sam e tissue block allows some degree of c e rtain ty . Of all the m ethods of approach which have been followed in the stu d y of the functional significance of the different hypophyseal cell tvpes, the technique of im m unochem istry appears to be the m ost specific and to hold the greatest prom ise for future progress [Baker, 1969].…”

Section: Discussionmentioning

confidence: 99%

Cytological and ultrastructural characterization of the human pituitary

Lawzewitsch¹,

Gh²,

Amezua³

et al. 1972

Cells Tissues Organs

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Differentiation of growth hormone‐ and prolactin‐containing acidophils with peroxidase‐labeled antibody

Cited by 72 publications

References 14 publications

Structural Correlates of Stimulated and Inhibited Secretion: Electron Microscopic Observations of Somatotrophs in Perifused Rat Pituitary

Structural Correlates of Stimulated and Inhibited Secretion: Electron Microscopic Observations of Somatotrophs in Perifused Rat Pituitary

Mammotroph and Gonadotroph Volume Percentage in the Rat Anterior Pituitary after Lesion of the Medial Basal Hypothalamus

Cytological and ultrastructural characterization of the human pituitary

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