Charles F. Cobb

Effects of ethanol and acetaldehyde on the rat adrenal

A pseudoCushing syndrome, indistinguishable from true Cushing syndrome except that it disappears with abstinence from alcohol, is known to occur in alcoholics. An animal model was used to study this syndrome in vitro, as earlier studies have shown that ethanol administration to animals increases corticosterone secretion. Such secretion appears to be the result of ethanol-induced ACTH secretion. We have examined the effects of ethanol and acetaldehyde on the production of three steroids: corticosterone, progesterone, and androstenedione in the isolated perfused rat adrenal. The adrenal glands and left kidney of rats were perfused with medium and one of the following additions: ethanol, acetaldehyde, ACTH or ACTH with either ethanol or acetaldehyde. The amount of the three steroids in the adrenal and the perfusion effluent was determined and compared to that of nonperfused adrenal glands. We found that perfusion with medium alone increased the production of each steroid (p less than 0.05) in the presence of ethanol or acetaldehyde. Assay of the medium before and after perfusion showed no ACTH, so that the increased steroid production cannot be ascribed to ACTH contamination. Furthermore, the addition of ACTH to perfusion medium which contained ethanol or acetaldehyde did not further enhance the responses.

Isolated testes perfusion: a method using a cell- and protein-free perfusate useful for the evaluation of potential drug and/or metabolic injury.

A method is described by which the testes and left kidney of the rat can be isolated, maintained, and selectively perfused in vitro to examine the effect of potential gonadal toxins. The integrity of the system was confirmed by demonstrating appropriate increases in steroid (testosterone and estradiol) production and secretion in response to stimulation with chorionic gonadotropin; maintenance of testicular ATP levels; and failure to observe an increase in perfusate concentration of transaminase and lactic dehydrogenase over 2 hr of perfusion. After such confirmation, the effect of two potential gonadal toxins, ethanol and acetaldehyde, at levels commonly found in the plasma of men who abuse alcohol, was evaluated using the system. Both of these substances significantly (p less than 0.01) reduced the testosterone production and secretory response of the isolated perfused testes. The advantages of such a system are that the effect of specific potential toxins independent of hepatic metabolism and/or hypothalamic-pituitary suppression by such substances can be identified and examined in a system free of extragonadal metabolism.

An evaluation of the respective roles of portosystemic shunting and portal hypertension in rats upon the production of gonadal dysfunction in cirrhosis.

To evaluate the differential effects of portal hypertension and portosystemic shunting upon the endocrine changes that occur in men with advanced chronic liver disease, male rats underwent either partial portal vein ligation or direct portocaval anastomosis. Testicular mass was found to be reduced in both models (p less than 0.05). Similarly, estradiol levels were found to be increased (p less than 0.05) in both models when compared with sham-operated controls. The increase in estradiol levels was greater in the animals with a complete shunt than in those animals with incomplete shunts developed as a consequence of portal hypertension (p less than 0.05). Luteinizing hormone levels were reduced (p less than 0.01) in the animals with the greater estradiol levels. As expected, testosterone levels were reduced (p less than 0.01) only in the animals with reduced luteinizing hormone levels. These data suggest that portosystemic shunting, and not portal hypertension per se, is responsible, at least in part, for the gonadal injury that occurs with advanced liver disease.

Ethanol, a Leydig cell toxin: Evidence obtained in vivo and in vitro

The available evidence which suggests that ethanol is a Leydig cell toxin is presented. Both in vivo and in vitro data are reviewed. The minor differences obtained in vitro as compared to those obtained in vivo are discussed. As a result of information obtained during the last decade, there can be little doubt that ethanol and possibly acetaldehyde are clinically important environmental Leydig cell toxins.

Alcohol and sexual function

The pathophysiologic factors which either document or which have been shown to be responsible for not only the hypogonadism and feminization of chronic alcoholic men but also the loss of gonadal function with resultant defeminization of chronic alcoholic women are reviewed. Evidence is presented which suggests that alcohol abuse is associated with the production of a primary form of hypogonadism characterized by loss of endocrine and reproductive function of the gonads. Moreover, evidence is presented which suggests that alcohol abuse is associated with the production of an associated hypothalamic-pituitary defect in gonadotropin secretion which prevents appropriate enhancement of gonadotropin secretion in response to the primary gonadal injury. Finally, the factors which have been found to partially explain the feminization often seen in chronic alcoholic men with advanced liver disease are discussed individually and a composite mechanism incorporating each is presented.

Is Ethanol a Testicular Toxin

A method is described by which the testis of the rat can be isolated and selectively perfused in vitro to examine the effect of potential gonadal toxins. Using this system, the effect of ethanol at levels commonly found in the plasma of nonalcoholic men who drink alcohol was evaluated. Ethanol was found to significantly reduce (p less than 0.01) testosterone production and secretion by the isolated perfused testis. The advantage of such a system is that it permits examination of the effect of specific testicular toxins, such as alcohol, independent of hepatic metabolism and/or hypothalamic-pituitary suppression by such substances. These results suggest that ethanol, independent of hepatic metabolism and/or hypothalamic-pituitary suppression, is a direct testicular toxin.

Consequences of complete bile-duct ligation on the pubertal process in the male rat

Prepubertal male rats underwent bile-duct ligation or a sham operation. Sham-operated animals were divided into two groups: isocalorically-fed (matched to the bile-duct-ligated animals) and ad-libitum-fed animals. At 60 days of age (after puberty in a male rat) all animals were killed. Bile-duct-ligated animals had larger livers, greater bilirubin, greater bile acid, greater aspartate transaminase, and greater alkaline phosphatase levels and lower testosterone and luteinizing hormone levels in their serum than did the controls. Moreover, the testes and seminal vesicles were smaller in the bile-duct-ligated animals than in the controls. These data suggest that chronic cholestasis contributes, at least in part, to the pubertal and maturational failure that occurs with the chronic cholestatic diseases of childhood.

Isolated rat adrenal perfusion: A new method to study adrenal function

To study the function of the rat adrenal glands directly, a method was developed whereby the adrenal glands are selectively isolated and perfused in situ. Under basal conditions the perfused adrenals synthesized 570 ± 68 (mean ± SEM) μg corticosterone per gram adrenal tissue in 90 min compared to 933 ± 132 μg/g adrenal tissue (P < 0.05) when the stimulus, ACTH, was added to the perfusate. Because nonperfused control adrenals contain only 25 ± 3 μg corticosterone per gram tissue, the perfused adrenals synthesized between 20 (basal) and 40 (stimulated) times (both P < 0.01) as much corticosterone as was present initially. Moreover, the amount synthesized was equal to that synthesized by the intact animal and considerably greater than that reported using other experimental methods. In addition, almost all of the corticosterone synthesized during perfusion was also secreted during perfusion.