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treat hypoventilation disorders. 12 Although plasma progesProgesterone and estradiol are metabolized in the terone is elevated in cirrhotic patients because of decreased liver and are elevated in patients with cirrhosis. Progeshepatic metabolism, progesterone has not been proved to terone stimulates ventilation by activating progesterone cause their hyperventilation. receptors in the central nervous system; estradiol mayWe propose estradiol as a contributing factor to respiratory facilitate progesterone's actions by increasing progesalkalosis, although this has not been examined in humans. terone receptors. This study evaluated whether progesEstradiol is metabolized by the liver into estriol, which has terone and estradiol contribute to the respiratory alkaminimal estrogen effects. Estradiol has no direct respiratory losis common in cirrhotic patients. Arterial blood gases stimulatory effect; 13 however, estradiol increases the number and progesterone and estradiol levels were obtained in of progesterone receptors in animals and may facilitate pro-50 patients with cirrhosis. Multiple linear regression regesterone's actions. 14,15 vealed a statistically significant correlation between This report examines the roles of hyperprogesteronemia P a CO 2 and progesterone and estradiol (r Å .54, P õ .05).and hyperestradiolemia in producing hyperventilation in paPatients with severe hyperventilation (P a CO 2°3 0 mm tients with cirrhosis. Hg) had statistically higher levels of progesterone and estradiol than did patients with mild hyperventilation PATIENTS AND METHODS (30 õ P a CO 2°3 5) or normal ventilation (P a CO 2 ú 35) (P õ .05). Although the progesterone levels were two orders With written patient consent and approval from the University of of magnitude lower than those associated with hyper-Rochester Investigational Review Board, we prospectively studied 50 ventilation in pregnant patients, the increased ventila-patients presenting to liver clinic for possible liver transplantation. tory effect may be because of the altered blood-brain Premenopausal women, patients with chronic obstructive pulmonary disease or acute encephalopathy, or patients taking hormonal medibarrier (BBB) present in cirrhotic patients. Progestercations, narcotics, or benzodiazepines were excluded. All patients one and estradiol appear to contribute to the hyperven- 58.)the wrist. A 20-gauge catheter was then placed in a sterile fashion into the radial artery and taped in place. To ensure no hyperventilation from anxiety or pain, arterial blood was drawn into a heparinized Respiratory alkalosis is common in patients with hepatic syringe after several minutes, the arterial blood was placed on ice, cirrhosis 1,2 although the cause has proved elusive. Proposed and sent to the lab for immediate determination of blood gas results. mechanisms include increased ammonia, 3 decreased albuBlood was also sent for determination of estradiol and progesterone min, 4 hypoxia, 5 and elevated progesterone. 6 levels. Albumin and bilirubin levels and prothrombi...

The effect of hypothalamic deafferentation upon levels of LH-RH in brain, cerebrospinal fluid, and plasma was studied in adult male rats. Deafferentation produced a significant increase in the LH-RH concentration of third ventricular CSF (from 140.6 to 343.9 pg/µl), while there was no change in median eminence or hypothalamic content. LH-RH in the pineal gland and the posterior pituitary was also elevated by hypothalamic isolation.

The effects of ether and pentobarbital anesthesia on hypothalamic and cere-brospinal fluid (CSF) LH-RH content were studied in male rats. Ether elevated hypothalamic LH-RH 30 min after a 3-min exposure; pentobarbital (30 mg/kg) caused no change. The ether-induced increase in LH-RH content was not affected by pretreatment with pentobarbital; however, the increase was abolished in animals subjected to hypothalamic deafferentation. Changes in CSF LH-RH generally paralleled the hypothalamic changes; ether, for example, elicited a significant rise. These results demonstrate the complex hypothalamo-pituitary-CSF interactions which occur in response to general anesthetics.

We compared the cardiovascular and hormonal responses to angiotensin converting enzyme inhibition and hemorrhage of 20% of blood volume in chronically instrumented unanesthetized newborn lambs and adult sheep. Administration of the nonsulfhydryl-containing converting-enzyme inhibitor enalapril reduced mean arterial pressure in the newborn but not in the adult animals. Blood pressure fell in both age groups after hemorrhage, and the hemorrhage-induced fall in blood pressure, integrated over the period of hypovolemia, was more pronounced when converting-enzyme inhibition was present in the lambs. This was not observed in the adults. Cardiac output fell following hemorrhage in both age groups, and the fall was greater when enalapril was present in the lambs, but this was not the case in the adults. Hemorrhage increased plasma renin activity in both groups, and enalapril augmented this increase. Plasma concentrations of vasopressin and catecholamines increased following hemorrhage within and between groups. Taken together these data suggest that the renin-angiotensin system plays a more important role in the maintenance of cardiovascular homeostasis in newborn lambs than it does in adult sheep, and catecholamine and vasopressin responses to volume loss can occur in the presence of blockade of the renin-angiotensin system.

Spontaneously hypertensive rats (SHRs) were compared to Wistar-Kyoto (WKY) and Wistar (WIS) rats on 18 behaviors to determine strain differences while undisturbed and when being restrained by a jacket and tether system often used for monitoring blood pressure chronically. Male SHRs unrestrained in the home cage initially exhibited greater magnitudes of body grooming, quadrant changes, turning, sniffing and rearing than WKYs, whose behavioral levels remained low throughout the entire session. SHRs and WISs gradually declined in behavioral levels within the sessions. The effects of restraint significantly decreased the exploratory/activity behaviors of nose poking, rearing and quadrant changes, with SHRs showing a greater decrement as a result of the restraint. Because of this differential effect of restraint on behaviors distinguishing SHRs and WKYs, studies simultaneously measuring behavior and blood pressure should be interpreted with caution, especially when comparing strains. The hypoactivity of the WKY would suggest the use of an additional control strain in behavioral studies.

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