Section of the Pituitry Stalk in the Rhesus Monkey

Vaughan, Leah; Carmel, Peter W.; Dyrenfurth, Inge; Frantz, Andrew G.; Antunes, J L; Ferin, Michel

doi:10.1159/000122978

Cited by 50 publications

(13 citation statements)

References 21 publications

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“…Our long-term ob servations on endocrine effects of stalk section in rhesus monkeys reported in an accompanying paper [22], chal lenge in part this general statement; we have indeed found persistence of basal growth hormone (GH) and cortisol secretion concomitant with increases in prolactin. In this communication, we report morphological studies on the effects of stalk section on the pars tuberalis and pars dista lis of the adenohypophysis.…”

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confidence: 55%

Section of the Pituitary Stalk in the Rhesus Monkey

Antunes¹,

Louis²,

Cogen³

et al. 1980

Neuroendocrinology

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The effects of pituitary stalk section on anterior pituitary morphology were studied in 18 female rhesus monkeys. 4 animals were studied within 1–14 days after the operation, while the others were examined later (average 17.2 months). In 3 monkeys there was no necrosis of the anterior lobe, whereas in the remaining animals, an area of infarction averaging 20% was found. Using immunocytochemical techniques, we found that corticotropes and somato-tropes were still present following the procedure, and that the number of lactotropes increased markedly. In contrast, gonadotropes, although present in the pars tuberalis, were no longer demonstrable in the pars distalis 3 weeks after stalk section. These results show remarkable agreement between endocrine studies and morphological observations, and indicate a variable degree of dependency of the various pituitary cells on central nervous system influences.

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confidence: 55%

Section of the Pituitary Stalk in the Rhesus Monkey

Antunes¹,

Louis²,

Cogen³

et al. 1980

Neuroendocrinology

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“…This surge can be mimicked during the early follicular phase, or in ovariectomized animals, by administration of oestradiol benzoate. It is also well established that pituitary gonadotrophin secretion is under the control of hypothalamic luteinizing hormone-releasing hormone (LHRH); thus, in monkeys chronically deprived of LHRH action by lesions in the arcuate nucleus (Knobil, 1980), pituitary stalk section (Vaughan et al, 1980), active immunization against LHRH (Fraser, 1983) or chronic treatment with an LHRH agonist or antagonist (Fraser, 1981;Kenigsberg et al, 1984) the oestro¬ gen-induced LH surge was found to be prevented. However, there is evidence to suggest that, in the primate, oestrogen can have a direct stimulatory effect on the pituitary in the absence of LHRH, provided that the pituitary has been primed previously by the decapeptide.…”

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confidence: 99%

Blockade of the oestrogen-induced LH surge in the ovariectomized common marmoset (Callithrix jacchus) by an LHRH antagonist

O’Byrne

Lunn²,

Fraser³

1989

Reproduction

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Summary. Six long-term ovariectomized adult marmoset monkeys were treated at 0 h with 35 \g=m\g oestradiol benzoate s.c. to induce an LH surge. They were also treated with detirelix (an LHRH antagonist) at 0 h, 12 h and 24 h (Exp. 1), or at 0 h and 24 h (Exp. 2) at a dose of 300 \g=m\g/kgs.c., or received the detirelix vehicle alone at 0 h, 12h and 24 h (Exp. 3). All animals received the three treatments, with at least 4 weeks between experiments. Blood samples were collected at 0 h and at 6\p=n-\12h intervals for 72 h after oestradiol for the determination of plasma LH by bioassay. In control animals, oestrogen treatment resulted in a decline in plasma LH from 30\m=.\0 \ m=+-\ 5\m=.\8at 0 h to 12\m=.\8 \ m=+-\ 2\m=.\6 ng/ml at 6 h (negative feedback), followed by a positive feedback surge, reaching a maximum of 148\m=.\0\m=+-\ 34\m=.\6ng/ml at 24h. Values then declined to pretreatment levels by 56h. In contrast, antagonist-treated animals showed complete abolition of the expected increase at 24 h, the low levels of the negative feedback phase being maintained for 36\p=n-\72h.These results show that hypothalamic LHRH release is essential during the oestrogen-induced LH surge, and that a direct oestrogen-induced component at the pituitary level is not expressed in the absence of LHRH in the marmoset.

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“…Studies conducted in experimental animals (1, 2), as well as in humans (3)(4)(5)(6), have demonstrated a classical pattern of change in pituitary hormone secretion when the pituitary stalk is sectioned or compressed by mass lesions such as a large pituitary adenoma (3), a carotid artery aneurysm (4), a meningioma (5), or a craniopharyngioma (6). Patients with pituitary stalk compression demonstrate mild hyperprolactinemia and loss of other pituitary hormone secretion (1)(2)(3)(4)(5)(6). Likewise, patients with large pituitary adenomas often present with similar clinical and biochemical features consisting of hypopituitarism and mild hyperprolactinemia (3,7).…”

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The Dominant Role of Increased Intrasellar Pressure in the Pathogenesis of Hypopituitarism, Hyperprolactinemia, and Headaches in Patients with Pituitary Adenomas*

Arafah¹,

Prunty

Ybarra³

et al. 2000

The Journal of Clinical Endocrinology &Amp; Metabolism

113

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Mild hyperprolactinemia frequently accompanies the hypopituitarism seen in patients with pituitary macroadenomas that do not secrete PRL. Recent data suggested that the hypopituitarism and mild hyperprolactinemia in this setting are largely due to compression of pituitary stalk and portal vessels. Headaches (HAs) are frequently seen in patients with large adenomas and at times in those with microadenomas. Because the walls of the sella turcica are relatively rigid, we postulate that tumor growth within the sella increases intrasellar pressure (ISP), which in turn impairs portal blood flow, resulting in mild hyperprolactinemia and hypopituitarism. We also postulate that increased mean ISP (MISP) contributes to the development of HAs. Normal MISP is not known but is unlikely to exceed normal intracranial pressure of less than 10 -15 mm Hg.We determined MISP in 49 patients who had transsphenoidal surgery for pituitary adenomas. MISP was measured using a commonly available intracranial monitoring kit where a fiberoptic transducer was inserted through a 2-mm dural incision at the time of adenomectomy. Patients with deficient FSH, LH, ACTH, or TSH secretion were considered hypopituitary. Data on serum PRL levels were included for analysis only in patients whose adenomas had negative immunostaining for the hormone.MISP measurements ranged from 7-56 mm Hg, with a mean (ϮSD) of 28.8 Ϯ 13.5 and a median of 26 mm Hg. The pressure measurements were higher in patients with hypopituitarism than in those with normal pituitary function (P ϭ 4.6013 ϫ 10 Ϫ6 ). Patients presenting with HAs had higher MISP than those who did not (P ϭ 5.44 ϫ 10 Ϫ7 ), regardless of their pituitary function or tumor sizes. PRL levels correlated positively with MISP values (r ϭ 0.715, P Ͻ 0.0001). Tumor size did not correlate with MISP or PRL levels.The findings of increased MISP in hypopituitary patients and the documented correlation with PRL levels, suggest that ISP is a major mechanism involved in the pathogenesis of hypopituitarism and hyperprolactinemia. Similarly, the increased MISP in patients with HAs, irrespective of tumor size or pituitary function, suggest that increased ISP is a major mechanism involved in the pathogenesis of this symptom. The data support the hypothesis that in patients with pituitary adenomas increased ISP is a major mechanism contributing to the development of hyperprolactinemia, hypopituitarism, and HAs. Increased ISP in these patients leads to compression of the portal vessels and the associated interruption of the delivery of hypothalamic hormones to the anterior pituitary. This would explain the reversibility of pituitary function observed in most patients after adenomectomy. However, increased ISP may also lead to decreased blood supply, resulting in ischemic necrosis in some regions of the pituitary. The latter could limit potential recovery of pituitary function after adenomectomy. (J Clin Endocrinol Metab 85: 1789 -1793, 2000 P HYSIOLOGIC secretion of pituitary hormones depends on the integrity of the h...

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Section of the Pituitry Stalk in the Rhesus Monkey

Cited by 50 publications

References 21 publications

Section of the Pituitary Stalk in the Rhesus Monkey

Section of the Pituitary Stalk in the Rhesus Monkey

Blockade of the oestrogen-induced LH surge in the ovariectomized common marmoset (Callithrix jacchus) by an LHRH antagonist

The Dominant Role of Increased Intrasellar Pressure in the Pathogenesis of Hypopituitarism, Hyperprolactinemia, and Headaches in Patients with Pituitary Adenomas*

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