Effect of gossypol on hepatic and serum gamma-glutamyltransferase activity in rats.

A single intraperitoneal dose (25 mg/kg) of gossypol given to male Sprague-Dawley rats caused marked changes in the activity of the hepatic and serum gamma-glutamyltransferase (GGT) and microsomal monooxygenases. The GGT activity in liver homogenate, S-9 supernatant fraction and microsomes was significantly depressed; however, the level of serum GGT was elevated. While the hepatic glutathione concentration was not greatly changed, the aminopyrine N-demethylase activity and microsomal cytochrome P450 content of the liver were significantly decreased in the treated rats. At necropsy, the livers of the treated rats appeared generally pale with distinct pinpoint foci. Histopathological examination of the liver showed degenerative changes and coagulative necrosis. The results indicate that gossypol is a strong hepatotoxic agent which can produce severe hepatic damage.

Primary hypertension in a colony of dogs.

A 5-year-old female Siberian husky that was diagnosed as an essential hypertensive was bred several times over a 5-year period, producing a colony of 39 offspring. Thirty of the 39 animals were subjected to biweekly systemic arterial blood pressure determinations with femoral arterial puncture and were placed into two hypertensive and two normotensive groups based on mean blood pressure: Group 1 (mean blood pressure, 128 +/- 12 mm Hg), Group 2 (mean blood pressure, 121 +/- 3 mm Hg), Group 3 (mean blood pressure, 114 +/- 8 mm Hg), and Group 4 (mean blood pressure, 101 +/- 9 mm Hg). Groups 1, 2, and 3 had mean blood pressures significantly higher than that of Group 4 (p less than 0.05). Ten dogs (representatives from Groups 1, 2, and 3) were subjected to more detailed clinical testing including angiography, echocardiography, ophthalmic examination, plasma catecholamine and renin activity measurements, plasma lead and cadmium determinations, cerebrospinal fluid examination, renal profile, and serum chemistry and hematological analysis. Five unrelated normotensive Siberian huskies were compared with colony dogs by using echocardiography. Groups 1 and 2 showed a clear but statistically insignificant upward trend in left ventricular wall thickness indexed against body weights when compared with that in Group 3 and in the unrelated five normal Siberian dogs. Thus, the only specific difference from group to group in the colony at the termination of this study was the difference in mean blood pressure. Based on these data, it is possible and likely that aging will reveal changes secondary to chronic primary hypertension. The pathogenesis of this hereditary disorder remains unknown.