Prostaglandin and HETE synthesis by aortae and hearts of normal and atherosclerotic rabbits.

New Zealand white rabbits were fed a diet enriched with cholesterol (0.25%) for 4 months. At that time, the aortae and coronary vessels of the cholesterol-fed rabbits were extensively covered with atherosclerotic lesions while those of age-matched control rabbits were normal. Langendorff-perfused hearts from the rabbits were compared for their ability to release PGI2 and PGE2 into the coronary sinus effluent during basal perfusion and after exposure to a bolus injection of 50 mumoles of arachidonic acid. No differences were detected in prostaglandin production between the cholesterol-fed and control animals. Nor were any differences in coronary hemodynamics observed. Aortic arachidonic acid metabolism was studied in an intimal en-face preparation. No differences were observed in the basal release of the PGI2 metabolite, 6-keto-PGF1 alpha, or PGE2. PGI2 and PGE2 production increased in response to arachidonic acid and to the calcium ionophore, A23187, but no differences were observed between cholesterol-fed or control tissues. Using minced aortic tissue, the production of 5-, 11-, 12- and 15-hydroxyeicosatetraenoic acids (HETE) were quantified by GC/MS. Differences in basal or A23187-stimulated HETE biosynthesis were not detected between the normal and atherosclerotic rabbit tissues. The data demonstrate that alterations in vascular prostaglandin and HETE are not prominent in rabbits with stable atherosclerosis produced by 4 months of cholesterol feeding.

Endocrine changes during pregnancy, parturition and the early post-partum period in the llama (Lama glama).

Mean (+/- s.d.) pregnancy length for the 14 llamas in this study was 350 +/- 4.5 days. Plasma progesterone concentrations increased by 5 days after mating and remained elevated (greater than 2.0 ng/ml) throughout most of pregnancy. At about 2 weeks before parturition, plasma progesterone concentrations began to decline, dropped markedly during the final 24 h before parturition, and returned to basal concentrations (less than 0.5 ng/ml) by the day of parturition. The combined oestrone + oestradiol-17 beta and oestradiol-17 beta concentrations varied between 6 and 274 pg/ml and 4 and 114 pg/ml, respectively, during the first 9 months of pregnancy. Concentrations increased between 9 months after mating and the end of pregnancy with peak mean concentrations of 827 +/- 58 (s.e.m.) pg oestrone + oestradiol-17 beta/ml (range: 64-1658) and 196 +/- 10 pg oestradiol-17 beta/ml (31-294) during the last week of pregnancy. Concentrations then declined to 87 +/- 14 pg oestrone + oestradiol-17 beta/ml (7-488) and 25 +/- 5 pg oestradiol-17 beta/ml (2.5-142) during the first week post partum. Plasma cortisol concentrations varied between 2.6 and 51.9 ng/ml (14.0 +/- 0.5) from mating until 2 weeks before parturition when the concentrations began to decline. Only a slight increase in plasma cortisol concentrations was observed in association with parturition. Plasma triiodothyronine concentrations varied between 0.5 and 4.5 ng/ml (1.9 +/- 0.1) throughout pregnancy and the periparturient period.(ABSTRACT TRUNCATED AT 250 WORDS)