pituitrin and Glaucoma

It has been postulated that intraocular pressure, an important glaucoma risk factor, correlates positively with arterial blood pressure (blood pressure). However, results of experimental and clinical studies are often contradictory. It is hypothesized that, in some hypertensive patients, disturbances in intraocular pressure regulation may depend on biological effects of blood borne hormones underlying a particular type of hypertension, rather than on blood pressure level itself.. This review compares the effects of hormones on blood pressure and intraocular pressure, in order to identify a hormonal profile of hypertensive patients with an increased risk of intraocular pressure surge. The PUBMED database was searched to identify pre-clinical and clinical studies investigating the role of angiotensin II, vasopressin, adrenaline, noradrenaline, prostaglandins, and gaseous transmitters in the regulation of blood pressure and intraocular pressure.. Studies included in the review suggest that intraocular and blood pressures often follow a different pattern of response to the same hormone. For example, vasopressin increases blood pressure, but decreases intraocular pressure. In contrast, high level of nitric oxide decreases blood pressure, but increases intraocular pressure.. Arterial hypertension is associated with altered levels of blood borne hormones. Contradicting results of studies on the relationship between arterial hypertension and intraocular pressure might be partially explained by diverse effects of hormones on arterial and intraocular pressures. Further studies are needed to evaluate if hormonal profiling may help to identify glaucoma-prone patients.

Topics: Blood Pressure; Glaucoma; Humans; Hypertension; Intraocular Pressure; Neurophysins; Protein Precursors; Vasopressins

Previous experiments have shown that arginine-vasopressin (AVP) reduces intraocular pressure (IOP) dose-dependently. The present study investigated the relationships between IOP, ciliary blood flow (CilBF), and aqueous flow (AqF) responses to AVP in anesthetized rabbits.. CilBF was measured by laser Doppler flowmetry and AqF by fluorophotometry. Mean arterial pressure (MAP) and IOP were monitored continuously and simultaneously. Perfusion pressure (PP) was varied mechanically. Four experimental protocols were performed: the dose-response (n = 11) and the pressure-flow relationship (n = 8) for CilBF and the effects on CilBF, and AqF at low (0.08 ng/kg/min; n = 14) and high AVP infusion rates (1.33 ng/kg/min; n = 12).. AVP decreased CilBF and IOP dose-dependently. At the low AVP infusion rate, AqF was reduced by 21.48% ± 2.52% without changing CilBF significantly. The high AVP infusion rate caused a 24.49% ± 3.53% decrease of AqF and a significant reduction in CilBF (35.60% ± 3.58%). IOP was reduced by 9.56% ± 2.35% at low and by 41.02% ± 3.19% at high AVP infusion rates. Based on the Goldmann equation, the decrease of AqF at the low AVP infusion rate accounted for 77.1% of the IOP reduction, whereas at the high AVP infusion rate, decreased AqF accounted for 28.4% of the IOP decline.. The results indicate that AVP can modulate IOP by different dose-dependent physiological mechanisms. The shifts of the CilBF-AqF relationship suggest that the reduction of AqF by the low AVP infusion rate is mainly provoked by inhibiting secretory processes in the ciliary epithelium. In contrast, at the high AVP infusion rate, the AqF reduction is caused by either reduced CilBF or more likely by a combined effect of reduced CilBF and secretory inhibition.

Topics: Animals; Aqueous Humor; Ciliary Body; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Fluorophotometry; Glaucoma; Infusions, Intravenous; Intraocular Pressure; Laser-Doppler Flowmetry; Male; Rabbits; Regional Blood Flow; Vasoconstrictor Agents; Vasopressins

Topics: Animals; Aqueous Humor; Ciliary Body; Female; Glaucoma; Intraocular Pressure; Male; Regional Blood Flow; Vasopressins

Various types of glaucomatous and normal subjects were tested for the adequacy of the stress response of their hypothalamic-pituitary-adrenal axis to pyrogen and vasopressin. With pyrogen, a significant response of elevation of plasma cortisol levels was positively correlated with ocular pressure and changes of the optic disc. Those subjects with increased ocular pressure and optic disc cupping and pallor had greater rises of plasma cortisol levels. With vasopressin, a decreased response of plasma cortisol levels was negatively correlated with the degree of elevated ocular pressure. Those subjects with increased ocular pressure and lower tonographic outflow facilities had smaller rises of plasma cortisol levels. Both tests indicated a disturbance of the hypothalamic-pituitary-adrenal axis in subjects with glaucoma.

Topics: Female; Glaucoma; Humans; Hydrocortisone; Hypothalamo-Hypophyseal System; Intraocular Pressure; Male; Middle Aged; Pituitary-Adrenal System; Polysaccharides, Bacterial; Pyrogens; Stress, Physiological; Vasopressins; Visual Acuity; Visual Fields

It has been shown in experiments on rabbits that alpha-and beta-adrenoblockers, and lithium chloride solution exert different effect on intraocular tension of healthy animals with experimental glaucoma and transitory hypertension. The beta-blockker obsidan decreases the tension in experimental glaucoma. Pretreatment with the drug prevents the development of glaucoma. On the contrary, the alpha-blocker pirroxan promotes the development of glaucoma and does not elicit any hypotensive therapeutic effect. The drug-induced decrease in intraocular tension was recorded in healthy animals and in rabbits with transitory hypertensin of the eye. The hypotensive effect of lithium was noted only in the animals with experimental glaucoma. The role of alpha-and beta-adrenergic receiption in the pathogenesis of glaucoma is discussed.

Topics: Adrenergic alpha-Antagonists; Animals; Dioxanes; Epinephrine; Glaucoma; Intraocular Pressure; Lithium; Propranolol; Pyrrolidines; Rabbits; Sympathetic Nervous System; Time Factors; Vasopressins

Topics: Animals; Anterior Chamber; Epinephrine; Glaucoma; Intraocular Pressure; Rabbits; Testosterone; Vasopressins

Topics: Adolescent; Adult; Aged; Dexamethasone; Diabetes Insipidus; Ethanol; Female; Glaucoma; Humans; Injections, Intravenous; Injections, Subcutaneous; Intraocular Pressure; Male; Middle Aged; Pituitary Gland, Posterior; Pituitary Neoplasms; Tonometry, Ocular; Vasopressins

Topics: Arginine Vasopressin; Glaucoma; Humans; Light; Vasopressins

Topics: Aqueous Humor; Eye; Glaucoma; Humans; Intraocular Pressure; Tonometry, Ocular; Vasopressins